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Joseph J, Prentout D, Laverré A, Tricou T, Duret L. High prevalence of PRDM9-independent recombination hotspots in placental mammals. Proc Natl Acad Sci U S A 2024; 121:e2401973121. [PMID: 38809707 PMCID: PMC11161765 DOI: 10.1073/pnas.2401973121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 04/26/2024] [Indexed: 05/31/2024] Open
Abstract
In many mammals, recombination events are concentrated in hotspots directed by a sequence-specific DNA-binding protein named PRDM9. Intriguingly, PRDM9 has been lost several times in vertebrates, and notably among mammals, it has been pseudogenized in the ancestor of canids. In the absence of PRDM9, recombination hotspots tend to occur in promoter-like features such as CpG islands. It has thus been proposed that one role of PRDM9 could be to direct recombination away from PRDM9-independent hotspots. However, the ability of PRDM9 to direct recombination hotspots has been assessed in only a handful of species, and a clear picture of how much recombination occurs outside of PRDM9-directed hotspots in mammals is still lacking. In this study, we derived an estimator of past recombination activity based on signatures of GC-biased gene conversion in substitution patterns. We quantified recombination activity in PRDM9-independent hotspots in 52 species of boreoeutherian mammals. We observe a wide range of recombination rates at these loci: several species (such as mice, humans, some felids, or cetaceans) show a deficit of recombination, while a majority of mammals display a clear peak of recombination. Our results demonstrate that PRDM9-directed and PRDM9-independent hotspots can coexist in mammals and that their coexistence appears to be the rule rather than the exception. Additionally, we show that the location of PRDM9-independent hotspots is relatively more stable than that of PRDM9-directed hotspots, but that PRDM9-independent hotspots nevertheless evolve slowly in concert with DNA hypomethylation.
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Affiliation(s)
- Julien Joseph
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR 5558, Villeurbanne69100, France
| | - Djivan Prentout
- Department of Biological Sciences, Columbia University, New York, NY10027
| | - Alexandre Laverré
- Department of Ecology and Evolution, University of Lausanne, LausanneCH-1015, Switzerland
- Swiss Institute of Bioinformatics, LausanneCH-1015, Switzerland
| | - Théo Tricou
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR 5558, Villeurbanne69100, France
| | - Laurent Duret
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR 5558, Villeurbanne69100, France
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2
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Joseph J. Increased Positive Selection in Highly Recombining Genes Does not Necessarily Reflect an Evolutionary Advantage of Recombination. Mol Biol Evol 2024; 41:msae107. [PMID: 38829800 PMCID: PMC11173204 DOI: 10.1093/molbev/msae107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/08/2024] [Accepted: 05/28/2024] [Indexed: 06/05/2024] Open
Abstract
It is commonly thought that the long-term advantage of meiotic recombination is to dissipate genetic linkage, allowing natural selection to act independently on different loci. It is thus theoretically expected that genes with higher recombination rates evolve under more effective selection. On the other hand, recombination is often associated with GC-biased gene conversion (gBGC), which theoretically interferes with selection by promoting the fixation of deleterious GC alleles. To test these predictions, several studies assessed whether selection was more effective in highly recombining genes (due to dissipation of genetic linkage) or less effective (due to gBGC), assuming a fixed distribution of fitness effects (DFE) for all genes. In this study, I directly derive the DFE from a gene's evolutionary history (shaped by mutation, selection, drift, and gBGC) under empirical fitness landscapes. I show that genes that have experienced high levels of gBGC are less fit and thus have more opportunities for beneficial mutations. Only a small decrease in the genome-wide intensity of gBGC leads to the fixation of these beneficial mutations, particularly in highly recombining genes. This results in increased positive selection in highly recombining genes that is not caused by more effective selection. Additionally, I show that the death of a recombination hotspot can lead to a higher dN/dS than its birth, but with substitution patterns biased towards AT, and only at selected positions. This shows that controlling for a substitution bias towards GC is therefore not sufficient to rule out the contribution of gBGC to signatures of accelerated evolution. Finally, although gBGC does not affect the fixation probability of GC-conservative mutations, I show that by altering the DFE, gBGC can also significantly affect nonsynonymous GC-conservative substitution patterns.
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Affiliation(s)
- Julien Joseph
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR 5558, Villeurbanne, France
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3
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Chen Z, Zhou M, Sun Y, Tang X, Zhang Z, Huang L. Exploration of Genome-Wide Recombination Rate Variation Patterns at Different Scales in Pigs. Animals (Basel) 2024; 14:1345. [PMID: 38731349 PMCID: PMC11083071 DOI: 10.3390/ani14091345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 04/27/2024] [Accepted: 04/28/2024] [Indexed: 05/13/2024] Open
Abstract
Meiotic recombination is a prevalent process in eukaryotic sexual reproduction organisms that plays key roles in genetic diversity, breed selection, and species evolution. However, the recombination events differ across breeds and even within breeds. In this study, we initially computed large-scale population recombination rates of both sexes using approximately 52 K SNP genotypes in a total of 3279 pigs from four different Chinese and Western breeds. We then constructed a high-resolution historical recombination map using approximately 16 million SNPs from a sample of unrelated individuals. Comparative analysis of porcine recombination events from different breeds and at different resolutions revealed the following observations: Firstly, the 1Mb-scale pig recombination maps of the same sex are moderately conserved among different breeds, with the similarity of recombination events between Western pigs and Chinese indigenous pigs being lower than within their respective groups. Secondly, we identified 3861 recombination hotspots in the genome and observed medium- to high-level correlation between historical recombination rates (0.542~0.683) and estimates of meiotic recombination rates. Third, we observed that recombination hotspots are significantly far from the transcription start sites of pig genes, and the silico-predicted PRDM9 zinc finger domain DNA recognition motif is significantly enriched in the regions of recombination hotspots compared to recombination coldspots, highlighting the potential role of PRDM9 in regulating recombination hotspots in pigs. Our study analyzed the variation patterns of the pig recombination map at broad and fine scales, providing a valuable reference for genomic selection breeding and laying a crucial foundation for further understanding the molecular mechanisms of pig genome recombination.
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Affiliation(s)
| | | | | | | | - Zhiyan Zhang
- National Key Laboratory for Swine Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang 330045, China
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4
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Armstrong EE, Bissell KL, Fatima HS, Heikkinen MA, Jessup A, Junaid MO, Lee DH, Lieb EC, Liem JT, Martin EM, Moreno M, Otgonbayar K, Romans BW, Royar K, Adler MB, Needle DB, Harkess A, Kelley JL, Mooney JA, Mychajliw AM. Chromosome-level assembly of the gray fox (Urocyon cinereoargenteus) confirms the basal loss of PRDM9 in Canidae. G3 (BETHESDA, MD.) 2024; 14:jkae034. [PMID: 38366575 PMCID: PMC10989890 DOI: 10.1093/g3journal/jkae034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Reference genome assemblies have been created from multiple lineages within the Canidae family; however, despite its phylogenetic relevance as a basal genus within the clade, there is currently no reference genome for the gray fox (Urocyon cinereoargenteus). Here, we present a chromosome-level assembly for the gray fox (U. cinereoargenteus), which represents the most contiguous, non-domestic canid reference genome available to date, with 90% of the genome contained in just 34 scaffolds and a contig N50 and scaffold N50 of 59.4 and 72.9 Megabases, respectively. Repeat analyses identified an increased number of simple repeats relative to other canids. Based on mitochondrial DNA, our Vermont sample clusters with other gray fox samples from the northeastern United States and contains slightly lower levels of heterozygosity than gray foxes on the west coast of California. This new assembly lays the groundwork for future studies to describe past and present population dynamics, including the delineation of evolutionarily significant units of management relevance. Importantly, the phylogenetic position of Urocyon allows us to verify the loss of PRDM9 functionality in the basal canid lineage, confirming that pseudogenization occurred at least 10 million years ago.
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Affiliation(s)
- Ellie E Armstrong
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Ky L Bissell
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - H Sophia Fatima
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Maya A Heikkinen
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Anika Jessup
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Maryam O Junaid
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Dong H Lee
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Emily C Lieb
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Josef T Liem
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Estelle M Martin
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Mauricio Moreno
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | | | - Betsy W Romans
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - Kim Royar
- Vermont Department of Fish and Wildlife, Montpelier, VT 05620, USA
| | - Mary Beth Adler
- Vermont Department of Fish and Wildlife, Montpelier, VT 05620, USA
| | - David B Needle
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Alex Harkess
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Joanna L Kelley
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jazlyn A Mooney
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90007, USA
| | - Alexis M Mychajliw
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
- Program in Environmental Studies, Middlebury College, Middlebury, VT 05753, USA
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5
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Versoza CJ, Weiss S, Johal R, La Rosa B, Jensen JD, Pfeifer SP. Novel Insights into the Landscape of Crossover and Noncrossover Events in Rhesus Macaques (Macaca mulatta). Genome Biol Evol 2024; 16:evad223. [PMID: 38051960 PMCID: PMC10773715 DOI: 10.1093/gbe/evad223] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 11/04/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023] Open
Abstract
Meiotic recombination landscapes differ greatly between distantly and closely related taxa, populations, individuals, sexes, and even within genomes; however, the factors driving this variation are yet to be well elucidated. Here, we directly estimate contemporary crossover rates and, for the first time, noncrossover rates in rhesus macaques (Macaca mulatta) from four three-generation pedigrees comprising 32 individuals. We further compare these results with historical, demography-aware, linkage disequilibrium-based recombination rate estimates. From paternal meioses in the pedigrees, 165 crossover events with a median resolution of 22.3 kb were observed, corresponding to a male autosomal map length of 2,357 cM-approximately 15% longer than an existing linkage map based on human microsatellite loci. In addition, 85 noncrossover events with a mean tract length of 155 bp were identified-similar to the tract lengths observed in the only other two primates in which noncrossovers have been studied to date, humans and baboons. Consistent with observations in other placental mammals with PRDM9-directed recombination, crossover (and to a lesser extent noncrossover) events in rhesus macaques clustered in intergenic regions and toward the chromosomal ends in males-a pattern in broad agreement with the historical, sex-averaged recombination rate estimates-and evidence of GC-biased gene conversion was observed at noncrossover sites.
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Affiliation(s)
- Cyril J Versoza
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA
| | - Sarah Weiss
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Ravneet Johal
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Bruno La Rosa
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Jeffrey D Jensen
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA
| | - Susanne P Pfeifer
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA
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6
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Abstract
The raison d'être of meiosis is shuffling of genetic information via Mendelian segregation and, within individual chromosomes, by DNA crossing-over. These outcomes are enabled by a complex cellular program in which interactions between homologous chromosomes play a central role. We first provide a background regarding the basic principles of this program. We then summarize the current understanding of the DNA events of recombination and of three processes that involve whole chromosomes: homolog pairing, crossover interference, and chiasma maturation. All of these processes are implemented by direct physical interaction of recombination complexes with underlying chromosome structures. Finally, we present convergent lines of evidence that the meiotic program may have evolved by coupling of this interaction to late-stage mitotic chromosome morphogenesis.
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Affiliation(s)
- Denise Zickler
- Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA;
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7
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Palahí I Torres A, Höök L, Näsvall K, Shipilina D, Wiklund C, Vila R, Pruisscher P, Backström N. The fine-scale recombination rate variation and associations with genomic features in a butterfly. Genome Res 2023; 33:810-823. [PMID: 37308293 PMCID: PMC10317125 DOI: 10.1101/gr.277414.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 05/03/2023] [Indexed: 06/14/2023]
Abstract
Recombination is a key molecular mechanism that has profound implications on both micro- and macroevolutionary processes. However, the determinants of recombination rate variation in holocentric organisms are poorly understood, in particular in Lepidoptera (moths and butterflies). The wood white butterfly (Leptidea sinapis) shows considerable intraspecific variation in chromosome numbers and is a suitable system for studying regional recombination rate variation and its potential molecular underpinnings. Here, we developed a large whole-genome resequencing data set from a population of wood whites to obtain high-resolution recombination maps using linkage disequilibrium information. The analyses revealed that larger chromosomes had a bimodal recombination landscape, potentially caused by interference between simultaneous chiasmata. The recombination rate was significantly lower in subtelomeric regions, with exceptions associated with segregating chromosome rearrangements, showing that fissions and fusions can have considerable effects on the recombination landscape. There was no association between the inferred recombination rate and base composition, supporting a limited influence of GC-biased gene conversion in butterflies. We found significant but variable associations between the recombination rate and the density of different classes of transposable elements, most notably a significant enrichment of short interspersed nucleotide elements in genomic regions with higher recombination rate. Finally, the analyses unveiled significant enrichment of genes involved in farnesyltranstransferase activity in recombination coldspots, potentially indicating that expression of transferases can inhibit formation of chiasmata during meiotic division. Our results provide novel information about recombination rate variation in holocentric organisms and have particular implications for forthcoming research in population genetics, molecular/genome evolution, and speciation.
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Affiliation(s)
- Aleix Palahí I Torres
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, SE-752 36 Uppsala, Sweden;
| | - Lars Höök
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, SE-752 36 Uppsala, Sweden
| | - Karin Näsvall
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, SE-752 36 Uppsala, Sweden
| | - Daria Shipilina
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, SE-752 36 Uppsala, Sweden
| | - Christer Wiklund
- Department of Zoology: Division of Ecology, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Roger Vila
- Butterfly Diversity and Evolution Lab, Institut de Biologia Evolutiva (CSIC-UPF), 08003 Barcelona, Spain
| | - Peter Pruisscher
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, SE-752 36 Uppsala, Sweden
| | - Niclas Backström
- Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, SE-752 36 Uppsala, Sweden
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8
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Mooney JA, Marsden CD, Yohannes A, Wayne RK, Lohmueller KE. Long-term Small Population Size, Deleterious Variation, and Altitude Adaptation in the Ethiopian Wolf, a Severely Endangered Canid. Mol Biol Evol 2023; 40:msac277. [PMID: 36585842 PMCID: PMC9847632 DOI: 10.1093/molbev/msac277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/07/2022] [Accepted: 12/22/2022] [Indexed: 01/01/2023] Open
Abstract
Ethiopian wolves, a canid species endemic to the Ethiopian Highlands, have been steadily declining in numbers for decades. Currently, out of 35 extant species, it is now one of the world's most endangered canids. Most conservation efforts have focused on preventing disease, monitoring movements and behavior, and assessing the geographic ranges of sub-populations. Here, we add an essential layer by determining the Ethiopian wolf's demographic and evolutionary history using high-coverage (∼40×) whole-genome sequencing from 10 Ethiopian wolves from the Bale Mountains. We observe exceptionally low diversity and enrichment of weakly deleterious variants in the Ethiopian wolves in comparison with two North American gray wolf populations and four dog breeds. These patterns are consequences of long-term small population size, rather than recent inbreeding. We infer the demographic history of the Ethiopian wolf and find it to be concordant with historic records and previous genetic analyses, suggesting Ethiopian wolves experienced a series of both ancient and recent bottlenecks, resulting in a census population size of fewer than 500 individuals and an estimated effective population size of approximately 100 individuals. Additionally, long-term small population size may have limited the accumulation of strongly deleterious recessive mutations. Finally, as the Ethiopian wolves have inhabited high-altitude areas for thousands of years, we searched for evidence of high-altitude adaptation, finding evidence of positive selection at a transcription factor in a hypoxia-response pathway [CREB-binding protein (CREBBP)]. Our findings are pertinent to continuing conservation efforts and understanding how demography influences the persistence of deleterious variation in small populations.
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Affiliation(s)
- Jazlyn A Mooney
- Department of Human Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Clare D Marsden
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
| | - Abigail Yohannes
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Robert K Wayne
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
| | - Kirk E Lohmueller
- Department of Human Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
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9
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AHLAWAT SONIKA, SHARMA REKHA, ARORA REENA, SHARMA HIMANI, SEHRAWAT RENUKA, SHARMA ANNU, SINGH KARANVEER, VIJH RAMESHKUMAR. Fertility of hybrids of dromedary and Bactrian camels: A possible role of conserved architecture of zinc finger domain of recombination regulator PRDM9. THE INDIAN JOURNAL OF ANIMAL SCIENCES 2022. [DOI: 10.56093/ijans.v92i12.112968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recombination regulator, PRDM9, has been regarded as the most rapidly evolving gene in the genomes of many metazoans, in addition to being acknowledged as the sole speciation gene in vertebrates. It has become the focus of many scientific investigations because of exceptional numerical and sequence variability in its zinc finger (ZF) domain within and across species that contributes to reproductive isolation between species. This study is the maiden attempt to explore the architecture of PRDM9 ZF domain in two Camelid species (Camelus dromedarius and Camelus bactrianus). Sequence analysis revealed highly conserved domain architecture with presence of 3 and 4 ZFs in dromedary and Bactrian camels, respectively. Typical evolutionary features of PRDM9 ZF domain i.e. concerted evolution and positive selection were invariably absent in both the one-humped dromedary and the two-humped Bactrian camels. Fertility of hybrids of dromedary and Bactrian camels, despite being taxonomically distinct species can be attributed to the lack of sequence variability in PRDM9 in these species. Phylogenetic analysis underpinned clear demarcation of camels from other livestock species. The results of the present study defy what has been learnt so far about PRDM9 and add to the enigma surrounding the most intriguing gene in the genome.
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10
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Protacio RU, Davidson MK, Wahls WP. Adaptive Control of the Meiotic Recombination Landscape by DNA Site-dependent Hotspots With Implications for Evolution. Front Genet 2022; 13:947572. [PMID: 35812747 PMCID: PMC9257126 DOI: 10.3389/fgene.2022.947572] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/01/2022] [Indexed: 02/04/2023] Open
Abstract
Meiosis is an essential component of the sexual life cycle in eukaryotes. The independent assortment of chromosomes in meiosis increases genetic diversity at the level of whole chromosomes and meiotic recombination increases genetic diversity within chromosomes. The resulting variability fuels evolution. Interestingly, global mapping of recombination in diverse taxa revealed dramatic changes in its frequency distribution between closely related species, subspecies, and even isolated populations of the same species. New insight into mechanisms for these evolutionarily rapid changes has come from analyses of environmentally induced plasticity of recombination in fission yeast. Many different DNA sites, and where identified their binding/activator proteins, control the positioning of recombination at hotspots. Each different class of hotspots functions as an independently controlled rheostat that modulates rates of recombination over a broad dynamic range in response to changing conditions. Together, this independent modulation can rapidly and dramatically alter the global frequency distribution of recombination. This process likely contributes substantially to (i.e., can largely explain) evolutionarily rapid, Prdm9-independent changes in the recombination landscape. Moreover, the precise control mechanisms allow cells to dynamically favor or disfavor newly arising combinations of linked alleles in response to changing extracellular and intracellular conditions, which has striking implications for the impacts of meiotic recombination on evolution.
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11
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PRDM9 losses in vertebrates are coupled to those of paralogs ZCWPW1 and ZCWPW2. Proc Natl Acad Sci U S A 2022; 119:2114401119. [PMID: 35217607 PMCID: PMC8892340 DOI: 10.1073/pnas.2114401119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2022] [Indexed: 01/12/2023] Open
Abstract
We take a phylogenetic approach to search for molecular partners of PRDM9, a key meiotic recombination gene, by leveraging the fact that the complete PRDM9 gene has been lost at least 13 times independently in vertebrates. We identify two genes, ZCWPW1 and its paralog ZCWPW2, whose presence or absence across vertebrates is coupled to that of PRDM9. ZCWPW1 was recently shown to be recruited to sites of PRDM9 binding and to aid in the repair of double strand breaks. ZCWPW2 is likely recruited to sites of PRDM9 binding as well; its tight coevolution with PRDM9 across vertebrates suggests that it too plays an important role in mammals and beyond, either in double strand break formation or repair. In most mammals and likely throughout vertebrates, the gene PRDM9 specifies the locations of meiotic double strand breaks; in mice and humans at least, it also aids in their repair. For both roles, many of the molecular partners remain unknown. Here, we take a phylogenetic approach to identify genes that may be interacting with PRDM9 by leveraging the fact that PRDM9 arose before the origin of vertebrates but was lost many times, either partially or entirely—and with it, its role in recombination. As a first step, we characterize PRDM9 domain composition across 446 vertebrate species, inferring at least 13 independent losses. We then use the interdigitation of PRDM9 orthologs across vertebrates to test whether it coevolved with any of 241 candidate genes coexpressed with PRDM9 in mice or associated with recombination phenotypes in mammals. Accounting for the phylogenetic relationship among a subsample of 189 species, we find two genes whose presence and absence is unexpectedly coincident with that of PRDM9: ZCWPW1, which was recently shown to facilitate double strand break repair, and its paralog ZCWPW2, as well as, more tentatively, TEX15 and FBXO47. ZCWPW2 is expected to be recruited to sites of PRDM9 binding; its tight coevolution with PRDM9 across vertebrates suggests that it is a key interactor within mammals and beyond, with a role either in recruiting the recombination machinery or in double strand break repair.
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12
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Protacio RU, Mukiza TO, Davidson MK, Wahls WP. Molecular mechanisms for environmentally induced and evolutionarily rapid redistribution (plasticity) of meiotic recombination. Genetics 2022; 220:iyab212. [PMID: 34888655 PMCID: PMC9097252 DOI: 10.1093/genetics/iyab212] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/15/2021] [Indexed: 02/04/2023] Open
Abstract
It has long been known (circa 1917) that environmental conditions, as well as speciation, can affect dramatically the frequency distribution of Spo11/Rec12-dependent meiotic recombination. Here, by analyzing DNA sequence-dependent meiotic recombination hotspots in the fission yeast Schizosaccharomyces pombe, we reveal a molecular basis for these phenomena. The impacts of changing environmental conditions (temperature, nutrients, and osmolarity) on local rates of recombination are mediated directly by DNA site-dependent hotspots (M26, CCAAT, and Oligo-C). This control is exerted through environmental condition-responsive signal transduction networks (involving Atf1, Pcr1, Php2, Php3, Php5, and Rst2). Strikingly, individual hotspots modulate rates of recombination over a very broad dynamic range in response to changing conditions. They can range from being quiescent to being highly proficient at promoting activity of the basal recombination machinery (Spo11/Rec12 complex). Moreover, each different class of hotspot functions as an independently controlled rheostat; a condition that increases the activity of one class can decrease the activity of another class. Together, the independent modulation of recombination rates by each different class of DNA site-dependent hotspots (of which there are many) provides a molecular mechanism for highly dynamic, large-scale changes in the global frequency distribution of meiotic recombination. Because hotspot-activating DNA sites discovered in fission yeast are conserved functionally in other species, this process can also explain the previously enigmatic, Prdm9-independent, evolutionarily rapid changes in hotspot usage between closely related species, subspecies, and isolated populations of the same species.
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Affiliation(s)
- Reine U Protacio
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA
| | - Tresor O Mukiza
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA
| | - Mari K Davidson
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA
| | - Wayne P Wahls
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA
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13
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Miyamae J, Okano M, Nishiya K, Katakura F, Kulski JK, Moritomo T, Shiina T. Haplotype structures and polymorphisms of dog leukocyte antigen (DLA) class I loci shaped by intralocus and interlocus recombination events. Immunogenetics 2022; 74:245-259. [PMID: 34993565 DOI: 10.1007/s00251-021-01234-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/10/2021] [Indexed: 11/26/2022]
Abstract
The dog leukocyte antigen (DLA) class I genomic region is located on chromosome 12, and the class I genomic region is composed of at least two distinct haplotypic gene structures, DLA-88-DLA-12 and DLA-88-DLA-88L. However, detailed information of the genomic differences among DLA-88, DLA-12, and DLA-88L are still lacking at the full-length gene level, and therefore, DLA allelic sequences classified for each of these loci are limited in number so far. In this study, we determined the DNA sequence of a 95-kb DLA class I genomic region including DLA-88, DLA-12/88L, and DLA-64 with three DLA homozygous dogs and of 37 full-length allelic gene sequences for DLA-88 and DLA-12/88L loci in 26 DLA class I homozygous dogs. Nucleotide diversity profiles of the 95-kb regions and sequence identity scores of the allelic sequences suggested that DLA-88L is a hybrid gene generated by interlocus and/or intralocus gene conversion between DLA-88 and DLA-12. The putative minimum conversion tract was estimated to be at least an 850-bp segment in length located from the 5´flanking untranslated region to the end of intron 2. In addition, at least one DLA-12 allele (DLA-12*004:01) was newly generated by interlocus gene conversion. In conclusion, the analysis for the occurrence of gene conversion within the dog DLA class I region revealed intralocus gene conversion tracts in 17 of 27 DLA-88 alleles and two of 10 DLA-12 alleles, suggesting that intralocus gene conversion has played an important role in expanding DLA allelic variations.
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Affiliation(s)
- Jiro Miyamae
- Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoino-oka, Imabari, Ehime, 794-8555, Japan.
| | - Masaharu Okano
- Department of Legal Medicine, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
| | - Kohei Nishiya
- Department of Veterinary Medicine, College of Bioresource Science, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan
| | - Fumihiko Katakura
- Department of Veterinary Medicine, College of Bioresource Science, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan
| | - Jerzy K Kulski
- Discipline of Psychiatry, Medical School, The University of Western Australia, Crawley, WA, Australia
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1143, Japan
| | - Tadaaki Moritomo
- Department of Veterinary Medicine, College of Bioresource Science, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan
| | - Takashi Shiina
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1143, Japan
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14
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Pilot M, Moura AE, Okhlopkov IM, Mamaev NV, Manaseryan NH, Hayrapetyan V, Kopaliani N, Tsingarska E, Alagaili AN, Mohammed OB, Ostrander EA, Bogdanowicz W. Human-modified canids in human-modified landscapes: The evolutionary consequences of hybridization for grey wolves and free-ranging domestic dogs. Evol Appl 2021; 14:2433-2456. [PMID: 34745336 PMCID: PMC8549620 DOI: 10.1111/eva.13257] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 05/05/2021] [Accepted: 05/19/2021] [Indexed: 12/22/2022] Open
Abstract
Introgressive hybridization between domestic animals and their wild relatives is an indirect form of human-induced evolution, altering gene pools and phenotypic traits of wild and domestic populations. Although this process is well documented in many taxa, its evolutionary consequences are poorly understood. In this study, we assess introgression patterns in admixed populations of Eurasian wolves and free-ranging domestic dogs (FRDs), identifying chromosomal regions with significantly overrepresented hybrid ancestry and assessing whether genes located within these regions show signatures of selection. Although the dog admixture proportion in West Eurasian wolves (2.7%) was greater than the wolf admixture proportion in FRDs (0.75%), the number and average length of chromosomal blocks showing significant overrepresentation of hybrid ancestry were smaller in wolves than FRDs. In wolves, 6% of genes located within these blocks showed signatures of positive selection compared to 23% in FRDs. We found that introgression from wolves may provide a considerable adaptive advantage to FRDs, counterbalancing some of the negative effects of domestication, which can include reduced genetic diversity and excessive tameness. In wolves, introgression from FRDs is mostly driven by drift, with a small number of positively selected genes associated with brain function and behaviour. The predominance of drift may be the consequence of small effective size of wolf populations, which reduces efficiency of selection for weakly advantageous or against weakly disadvantageous introgressed variants. Small wolf population sizes result largely from human-induced habitat loss and hunting, thus linking introgression rates to anthropogenic processes. Our results imply that maintenance of large population sizes should be an important element of wolf management strategies aimed at reducing introgression rates of dog-derived variants.
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Affiliation(s)
- Małgorzata Pilot
- Museum and Institute of ZoologyPolish Academy of SciencesWarsawPoland
| | - Andre E. Moura
- Museum and Institute of ZoologyPolish Academy of SciencesWarsawPoland
| | - Innokentiy M. Okhlopkov
- Institute of Biological Problems of CryolithozoneSiberian Branch of Russian Academy of SciencesYakutskRussia
| | - Nikolay V. Mamaev
- Institute of Biological Problems of CryolithozoneSiberian Branch of Russian Academy of SciencesYakutskRussia
| | - Ninna H. Manaseryan
- Scientific Center of Zoology and HydroecologyNational Academy of SciencesYerevanArmenia
| | | | | | | | - Abdulaziz N. Alagaili
- KSU Mammals Research ChairDepartment of ZoologyKing Saud UniversityRiyadhSaudi Arabia
| | - Osama B. Mohammed
- KSU Mammals Research ChairDepartment of ZoologyKing Saud UniversityRiyadhSaudi Arabia
| | - Elaine A. Ostrander
- Cancer Genetics and Comparative Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
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15
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Axelsson E, Ljungvall I, Bhoumik P, Conn LB, Muren E, Ohlsson Å, Olsen LH, Engdahl K, Hagman R, Hanson J, Kryvokhyzha D, Pettersson M, Grenet O, Moggs J, Del Rio-Espinola A, Epe C, Taillon B, Tawari N, Mane S, Hawkins T, Hedhammar Å, Gruet P, Häggström J, Lindblad-Toh K. The genetic consequences of dog breed formation-Accumulation of deleterious genetic variation and fixation of mutations associated with myxomatous mitral valve disease in cavalier King Charles spaniels. PLoS Genet 2021; 17:e1009726. [PMID: 34473707 PMCID: PMC8412370 DOI: 10.1371/journal.pgen.1009726] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/20/2021] [Indexed: 02/07/2023] Open
Abstract
Selective breeding for desirable traits in strictly controlled populations has generated an extraordinary diversity in canine morphology and behaviour, but has also led to loss of genetic variation and random entrapment of disease alleles. As a consequence, specific diseases are now prevalent in certain breeds, but whether the recent breeding practice led to an overall increase in genetic load remains unclear. Here we generate whole genome sequencing (WGS) data from 20 dogs per breed from eight breeds and document a ~10% rise in the number of derived alleles per genome at evolutionarily conserved sites in the heavily bottlenecked cavalier King Charles spaniel breed (cKCs) relative to in most breeds studied here. Our finding represents the first clear indication of a relative increase in levels of deleterious genetic variation in a specific breed, arguing that recent breeding practices probably were associated with an accumulation of genetic load in dogs. We then use the WGS data to identify candidate risk alleles for the most common cause for veterinary care in cKCs–the heart disease myxomatous mitral valve disease (MMVD). We verify a potential link to MMVD for candidate variants near the heart specific NEBL gene in a dachshund population and show that two of the NEBL candidate variants have regulatory potential in heart-derived cell lines and are associated with reduced NEBL isoform nebulette expression in papillary muscle (but not in mitral valve, nor in left ventricular wall). Alleles linked to reduced nebulette expression may hence predispose cKCs and other breeds to MMVD via loss of papillary muscle integrity. As a consequence of selective breeding, specific disease-causing mutations have become more frequent in certain dog breeds. Whether the breeding practice also resulted in a general increase in the overall number of disease-causing mutations per dog genome is however not clear. To address this question, we compare the amount of harmful, potentially disease-causing, mutations in dogs from eight common breeds that have experienced varying degrees of intense selective breeding. We find that individuals belonging to the breed affected by the most intense breeding—cavalier King Charles spaniel (cKCs)—carry more harmful variants than other breeds, indicating that past breeding practices may have increased the overall levels of harmful genetic variation in dogs. The most common disease in cKCs is myxomatous mitral valve disease (MMVD). To identify variants linked to this disease we next characterize mutations that are common in cKCs, but rare in other breeds, and then investigate if these mutations can predict MMVD in dachshunds. We find that variants that regulate the expression of the gene NEBL in papillary muscles may increase the risk of the disease, indicating that loss of papillary muscle integrity could contribute to the development of MMVD.
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Affiliation(s)
- Erik Axelsson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- * E-mail:
| | - Ingrid Ljungvall
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Priyasma Bhoumik
- Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Laura Bas Conn
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Eva Muren
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Åsa Ohlsson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Lisbeth Høier Olsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karolina Engdahl
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ragnvi Hagman
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jeanette Hanson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Dmytro Kryvokhyzha
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Mats Pettersson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Olivier Grenet
- Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Jonathan Moggs
- Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Christian Epe
- Elanco Animal Health, Greenfield, Indiana, United States of America
| | - Bruce Taillon
- Elanco Animal Health, Greenfield, Indiana, United States of America
| | - Nilesh Tawari
- Elanco Animal Health, Greenfield, Indiana, United States of America
| | - Shrinivas Mane
- Elanco Animal Health, Greenfield, Indiana, United States of America
| | - Troy Hawkins
- Elanco Animal Health, Greenfield, Indiana, United States of America
| | - Åke Hedhammar
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Jens Häggström
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Kerstin Lindblad-Toh
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
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16
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Hasan AR, Ness RW. Recombination Rate Variation and Infrequent Sex Influence Genetic Diversity in Chlamydomonas reinhardtii. Genome Biol Evol 2021; 12:370-380. [PMID: 32181819 PMCID: PMC7186780 DOI: 10.1093/gbe/evaa057] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2020] [Indexed: 12/12/2022] Open
Abstract
Recombination confers a major evolutionary advantage by breaking up linkage disequilibrium between harmful and beneficial mutations, thereby facilitating selection. However, in species that are only periodically sexual, such as many microbial eukaryotes, the realized rate of recombination is also affected by the frequency of sex, meaning that infrequent sex can increase the effects of selection at linked sites despite high recombination rates. Despite this, the rate of sex of most facultatively sexual species is unknown. Here, we use genomewide patterns of linkage disequilibrium to infer fine-scale recombination rate variation in the genome of the facultatively sexual green alga Chlamydomonas reinhardtii. We observe recombination rate variation of up to two orders of magnitude and find evidence of recombination hotspots across the genome. Recombination rate is highest flanking genes, consistent with trends observed in other nonmammalian organisms, though intergenic recombination rates vary by intergenic tract length. We also find a positive relationship between nucleotide diversity and physical recombination rate, suggesting a widespread influence of selection at linked sites in the genome. Finally, we use estimates of the effective rate of recombination to calculate the rate of sex that occurs in natural populations, estimating a sexual cycle roughly every 840 generations. We argue that the relatively infrequent rate of sex and large effective population size creates a population genetic environment that increases the influence of selection on linked sites across the genome.
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Affiliation(s)
- Ahmed R Hasan
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada.,Department of Biology, University of Toronto Mississauga, Ontario, Canada
| | - Rob W Ness
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada.,Department of Biology, University of Toronto Mississauga, Ontario, Canada
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17
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Mihola O, Landa V, Pratto F, Brick K, Kobets T, Kusari F, Gasic S, Smagulova F, Grey C, Flachs P, Gergelits V, Tresnak K, Silhavy J, Mlejnek P, Camerini-Otero RD, Pravenec M, Petukhova GV, Trachtulec Z. Rat PRDM9 shapes recombination landscapes, duration of meiosis, gametogenesis, and age of fertility. BMC Biol 2021; 19:86. [PMID: 33910563 PMCID: PMC8082845 DOI: 10.1186/s12915-021-01017-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 04/01/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Vertebrate meiotic recombination events are concentrated in regions (hotspots) that display open chromatin marks, such as trimethylation of lysines 4 and 36 of histone 3 (H3K4me3 and H3K36me3). Mouse and human PRDM9 proteins catalyze H3K4me3 and H3K36me3 and determine hotspot positions, whereas other vertebrates lacking PRDM9 recombine in regions with chromatin already opened for another function, such as gene promoters. While these other vertebrate species lacking PRDM9 remain fertile, inactivation of the mouse Prdm9 gene, which shifts the hotspots to the functional regions (including promoters), typically causes gross fertility reduction; and the reasons for these species differences are not clear. RESULTS We introduced Prdm9 deletions into the Rattus norvegicus genome and generated the first rat genome-wide maps of recombination-initiating double-strand break hotspots. Rat strains carrying the same wild-type Prdm9 allele shared 88% hotspots but strains with different Prdm9 alleles only 3%. After Prdm9 deletion, rat hotspots relocated to functional regions, about 40% to positions corresponding to Prdm9-independent mouse hotspots, including promoters. Despite the hotspot relocation and decreased fertility, Prdm9-deficient rats of the SHR/OlaIpcv strain produced healthy offspring. The percentage of normal pachytene spermatocytes in SHR-Prdm9 mutants was almost double than in the PWD male mouse oligospermic sterile mutants. We previously found a correlation between the crossover rate and sperm presence in mouse Prdm9 mutants. The crossover rate of SHR is more similar to sperm-carrying mutant mice, but it did not fully explain the fertility of the SHR mutants. Besides mild meiotic arrests at rat tubular stages IV (mid-pachytene) and XIV (metaphase), we also detected postmeiotic apoptosis of round spermatids. We found delayed meiosis and age-dependent fertility in both sexes of the SHR mutants. CONCLUSIONS We hypothesize that the relative increased fertility of rat versus mouse Prdm9 mutants could be ascribed to extended duration of meiotic prophase I. While rat PRDM9 shapes meiotic recombination landscapes, it is unnecessary for recombination. We suggest that PRDM9 has additional roles in spermatogenesis and speciation-spermatid development and reproductive age-that may help to explain male-specific hybrid sterility.
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Affiliation(s)
- Ondrej Mihola
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Vladimir Landa
- Laboratory of Genetics of Model Diseases, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Florencia Pratto
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kevin Brick
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tatyana Kobets
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Fitore Kusari
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Srdjan Gasic
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Fatima Smagulova
- Department of Biochemistry and Molecular Biology, Uniformed Services University of Health Sciences, Bethesda, MD, 20814, USA
- Present address: Inserm U1085 IRSET, 35042, Rennes, France
| | - Corinne Grey
- Institut de Génétique Humaine, CNRS UMR 9002, 34396, Montpellier, France
| | - Petr Flachs
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
- Present address: Division BIOCEV, Laboratory of Epigenetics of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Vaclav Gergelits
- Laboratory of Mouse Molecular Genetics, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Karel Tresnak
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic
| | - Jan Silhavy
- Laboratory of Genetics of Model Diseases, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Mlejnek
- Laboratory of Genetics of Model Diseases, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - R Daniel Camerini-Otero
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michal Pravenec
- Laboratory of Genetics of Model Diseases, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Galina V Petukhova
- Department of Biochemistry and Molecular Biology, Uniformed Services University of Health Sciences, Bethesda, MD, 20814, USA
| | - Zdenek Trachtulec
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220, Prague, Czech Republic.
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18
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Abstract
Recombination increases the local GC-content in genomic regions through GC-biased gene conversion (gBGC). The recent discovery of a large genomic region with extreme GC-content in the fat sand rat Psammomys obesus provides a model to study the effects of gBGC on chromosome evolution. Here, we compare the GC-content and GC-to-AT substitution patterns across protein-coding genes of four gerbil species and two murine rodents (mouse and rat). We find that the known high-GC region is present in all the gerbils, and is characterized by high substitution rates for all mutational categories (AT-to-GC, GC-to-AT, and GC-conservative) both at synonymous and nonsynonymous sites. A higher AT-to-GC than GC-to-AT rate is consistent with the high GC-content. Additionally, we find more than 300 genes outside the known region with outlying values of AT-to-GC synonymous substitution rates in gerbils. Of these, over 30% are organized into at least 17 large clusters observable at the megabase-scale. The unusual GC-skewed substitution pattern suggests the evolution of genomic regions with very high recombination rates in the gerbil lineage, which can lead to a runaway increase in GC-content. Our results imply that rapid evolution of GC-content is possible in mammals, with gerbil species providing a powerful model to study the mechanisms of gBGC.
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Affiliation(s)
- Rodrigo Pracana
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - John F Mulley
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, United Kingdom
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19
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Schield DR, Pasquesi GIM, Perry BW, Adams RH, Nikolakis ZL, Westfall AK, Orton RW, Meik JM, Mackessy SP, Castoe TA. Snake Recombination Landscapes Are Concentrated in Functional Regions despite PRDM9. Mol Biol Evol 2021; 37:1272-1294. [PMID: 31926008 DOI: 10.1093/molbev/msaa003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Meiotic recombination in vertebrates is concentrated in hotspots throughout the genome. The location and stability of hotspots have been linked to the presence or absence of PRDM9, leading to two primary models for hotspot evolution derived from mammals and birds. Species with PRDM9-directed recombination have rapid turnover of hotspots concentrated in intergenic regions (i.e., mammals), whereas hotspots in species lacking PRDM9 are concentrated in functional regions and have greater stability over time (i.e., birds). Snakes possess PRDM9, yet virtually nothing is known about snake recombination. Here, we examine the recombination landscape and test hypotheses about the roles of PRDM9 in rattlesnakes. We find substantial variation in recombination rate within and among snake chromosomes, and positive correlations between recombination rate and gene density, GC content, and genetic diversity. Like mammals, snakes appear to have a functional and active PRDM9, but rather than being directed away from genes, snake hotspots are concentrated in promoters and functional regions-a pattern previously associated only with species that lack a functional PRDM9. Snakes therefore provide a unique example of recombination landscapes in which PRDM9 is functional, yet recombination hotspots are associated with functional genic regions-a combination of features that defy existing paradigms for recombination landscapes in vertebrates. Our findings also provide evidence that high recombination rates are a shared feature of vertebrate microchromosomes. Our results challenge previous assumptions about the adaptive role of PRDM9 and highlight the diversity of recombination landscape features among vertebrate lineages.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | | | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, TX.,Department of Computer & Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, FL
| | | | | | - Richard W Orton
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, TX
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX
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20
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Halo JV, Pendleton AL, Shen F, Doucet AJ, Derrien T, Hitte C, Kirby LE, Myers B, Sliwerska E, Emery S, Moran JV, Boyko AR, Kidd JM. Long-read assembly of a Great Dane genome highlights the contribution of GC-rich sequence and mobile elements to canine genomes. Proc Natl Acad Sci U S A 2021; 118:e2016274118. [PMID: 33836575 PMCID: PMC7980453 DOI: 10.1073/pnas.2016274118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Technological advances have allowed improvements in genome reference sequence assemblies. Here, we combined long- and short-read sequence resources to assemble the genome of a female Great Dane dog. This assembly has improved continuity compared to the existing Boxer-derived (CanFam3.1) reference genome. Annotation of the Great Dane assembly identified 22,182 protein-coding gene models and 7,049 long noncoding RNAs, including 49 protein-coding genes not present in the CanFam3.1 reference. The Great Dane assembly spans the majority of sequence gaps in the CanFam3.1 reference and illustrates that 2,151 gaps overlap the transcription start site of a predicted protein-coding gene. Moreover, a subset of the resolved gaps, which have an 80.95% median GC content, localize to transcription start sites and recombination hotspots more often than expected by chance, suggesting the stable canine recombinational landscape has shaped genome architecture. Alignment of the Great Dane and CanFam3.1 assemblies identified 16,834 deletions and 15,621 insertions, as well as 2,665 deletions and 3,493 insertions located on secondary contigs. These structural variants are dominated by retrotransposon insertion/deletion polymorphisms and include 16,221 dimorphic canine short interspersed elements (SINECs) and 1,121 dimorphic long interspersed element-1 sequences (LINE-1_Cfs). Analysis of sequences flanking the 3' end of LINE-1_Cfs (i.e., LINE-1_Cf 3'-transductions) suggests multiple retrotransposition-competent LINE-1_Cfs segregate among dog populations. Consistent with this conclusion, we demonstrate that a canine LINE-1_Cf element with intact open reading frames can retrotranspose its own RNA and that of a SINEC_Cf consensus sequence in cultured human cells, implicating ongoing retrotransposon activity as a driver of canine genetic variation.
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Affiliation(s)
- Julia V Halo
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Amanda L Pendleton
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Feichen Shen
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Aurélien J Doucet
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
- Université Côte d'Azur, CNRS, INSERM, Institut de Recherche sur le Cancer et le Vieillissement de Nice, F-06100 Nice, France
| | - Thomas Derrien
- Université de Rennes 1, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, F-35000 Rennes, France
| | - Christophe Hitte
- Université de Rennes 1, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, F-35000 Rennes, France
| | - Laura E Kirby
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Bridget Myers
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Elzbieta Sliwerska
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Sarah Emery
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - John V Moran
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Adam R Boyko
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14850
| | - Jeffrey M Kidd
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109;
- Department Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109
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21
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Wang C, Wallerman O, Arendt ML, Sundström E, Karlsson Å, Nordin J, Mäkeläinen S, Pielberg GR, Hanson J, Ohlsson Å, Saellström S, Rönnberg H, Ljungvall I, Häggström J, Bergström TF, Hedhammar Å, Meadows JRS, Lindblad-Toh K. A novel canine reference genome resolves genomic architecture and uncovers transcript complexity. Commun Biol 2021; 4:185. [PMID: 33568770 PMCID: PMC7875987 DOI: 10.1038/s42003-021-01698-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
We present GSD_1.0, a high-quality domestic dog reference genome with chromosome length scaffolds and contiguity increased 55-fold over CanFam3.1. Annotation with generated and existing long and short read RNA-seq, miRNA-seq and ATAC-seq, revealed that 32.1% of lifted over CanFam3.1 gaps harboured previously hidden functional elements, including promoters, genes and miRNAs in GSD_1.0. A catalogue of canine "dark" regions was made to facilitate mapping rescue. Alignment in these regions is difficult, but we demonstrate that they harbour trait-associated variation. Key genomic regions were completed, including the Dog Leucocyte Antigen (DLA), T Cell Receptor (TCR) and 366 COSMIC cancer genes. 10x linked-read sequencing of 27 dogs (19 breeds) uncovered 22.1 million SNPs, indels and larger structural variants. Subsequent intersection with protein coding genes showed that 1.4% of these could directly influence gene products, and so provide a source of normal or aberrant phenotypic modifications.
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Affiliation(s)
- Chao Wang
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
| | - Ola Wallerman
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Maja-Louise Arendt
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg D, Denmark
| | - Elisabeth Sundström
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Åsa Karlsson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Jessika Nordin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Suvi Mäkeläinen
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Gerli Rosengren Pielberg
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Jeanette Hanson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Åsa Ohlsson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sara Saellström
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Henrik Rönnberg
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ingrid Ljungvall
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jens Häggström
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tomas F Bergström
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Åke Hedhammar
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jennifer R S Meadows
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Kerstin Lindblad-Toh
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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22
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Sams AJ, Ford B, Gardner A, Boyko AR. Examination of the efficacy of small genetic panels in genomic conservation of companion animal populations. Evol Appl 2020; 13:2555-2565. [PMID: 33294008 PMCID: PMC7691451 DOI: 10.1111/eva.13038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/26/2020] [Accepted: 04/29/2020] [Indexed: 11/30/2022] Open
Abstract
In many ways, dogs are an ideal model for the study of genetic erosion and population recovery, problems of major concern in the field of conservation genetics. Genetic diversity in many dog breeds has been declining systematically since the beginning of the 1800s, when modern breeding practices came into fashion. As such, inbreeding in domestic dog breeds is substantial and widespread and has led to an increase in recessive deleterious mutations of high effect as well as general inbreeding depression. Pedigrees can in theory be used to guide breeding decisions, though are often incomplete and do not reflect the full history of inbreeding. Small microsatellite panels are also used in some cases to choose mating pairs to produce litters with low levels of inbreeding. However, the long-term impact of such practices has not been thoroughly evaluated. Here, we use forward simulation on a model of the dog genome to examine the impact of using limited marker panels to guide pairwise mating decisions on genome-wide population-level genetic diversity. Our results suggest that in unmanaged populations, where breeding decisions are made at the pairwise-rather than population-level, such panels can lead to accelerated loss of genetic diversity at genome regions unlinked to panel markers, compared to random mating. These results demonstrate the importance of genome-wide genetic panels for managing and conserving genetic diversity in dogs and other companion animals.
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Affiliation(s)
| | - Brett Ford
- Embark Veterinary, IncorporatedBostonMAUSA
| | | | - Adam R. Boyko
- Embark Veterinary, IncorporatedBostonMAUSA
- Department of Biomedical SciencesCollege of Veterinary MedicineCornell UniversityIthacaNYUSA
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23
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Feigin CY, Newton AH, Pask AJ. Widespread cis-regulatory convergence between the extinct Tasmanian tiger and gray wolf. Genome Res 2019; 29:1648-1658. [PMID: 31533979 PMCID: PMC6771401 DOI: 10.1101/gr.244251.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 08/19/2019] [Indexed: 12/18/2022]
Abstract
The extinct marsupial Tasmanian tiger, or thylacine, and the eutherian gray wolf are among the most widely recognized examples of convergent evolution in mammals. Despite being distantly related, these large predators independently evolved extremely similar craniofacial morphologies, and evidence suggests that they filled similar ecological niches. Previous analyses revealed little evidence of adaptive convergence between their protein-coding genes. Thus, the genetic basis of their convergence is still unclear. Here, we identified candidate craniofacial cis-regulatory elements across vertebrates and compared their evolutionary rates in the thylacine and wolf, revealing abundant signatures of convergent positive selection. Craniofacial thylacine-wolf accelerated regions were enriched near genes involved in TGF beta (TGFB) and BMP signaling, both of which are key morphological signaling pathways with critical roles in establishing the identities and boundaries between craniofacial tissues. Similarly, enhancers of genes involved in craniofacial nerve development showed convergent selection and involvement in these pathways. Taken together, these results suggest that adaptation in cis-regulators of TGF beta and BMP signaling may provide a mechanism to explain the coevolution of developmentally and functionally integrated craniofacial structures in these species. We also found that despite major structural differences in marsupial and eutherian brains, accelerated regions in both species were common near genes with roles in brain development. Our findings support the hypothesis that, relative to protein-coding genes, positive selection on cis-regulatory elements is likely to be an essential driver of adaptive convergent evolution and may underpin thylacine-wolf phenotypic similarities.
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Affiliation(s)
- Charles Y Feigin
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia.,Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Axel H Newton
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia.,Museums Victoria, Melbourne, Victoria 3053, Australia
| | - Andrew J Pask
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia.,Museums Victoria, Melbourne, Victoria 3053, Australia
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24
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Li R, Bitoun E, Altemose N, Davies RW, Davies B, Myers SR. A high-resolution map of non-crossover events reveals impacts of genetic diversity on mammalian meiotic recombination. Nat Commun 2019; 10:3900. [PMID: 31467277 PMCID: PMC6715734 DOI: 10.1038/s41467-019-11675-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 07/17/2019] [Indexed: 12/21/2022] Open
Abstract
During meiotic recombination, homologue-templated repair of programmed DNA double-strand breaks (DSBs) produces relatively few crossovers and many difficult-to-detect non-crossovers. By intercrossing two diverged mouse subspecies over five generations and deep-sequencing 119 offspring, we detect thousands of crossover and non-crossover events genome-wide with unprecedented power and spatial resolution. We find that both crossovers and non-crossovers are strongly depleted at DSB hotspots where the DSB-positioning protein PRDM9 fails to bind to the unbroken homologous chromosome, revealing that PRDM9 also functions to promote homologue-templated repair. Our results show that complex non-crossovers are much rarer in mice than humans, consistent with complex events arising from accumulated non-programmed DNA damage. Unexpectedly, we also find that GC-biased gene conversion is restricted to non-crossover tracts containing only one mismatch. These results demonstrate that local genetic diversity profoundly alters meiotic repair pathway decisions via at least two distinct mechanisms, impacting genome evolution and Prdm9-related hybrid infertility. During meiotic recombination, genetic information is transferred or exchanged between parental chromosome copies. Using a large hybrid mouse pedigree, the authors generated high-resolution maps of these transfer/exchange events and discovered new properties governing their processing and resolution.
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Affiliation(s)
- Ran Li
- The Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, UK.,Department of Statistics, University of Oxford, 24-29 St Giles', Oxford, OX1 3LB, UK.,Target Discovery Institute, NDM Research Building, University of Oxford, Old Road Campus, Headington, Oxford, OX3 7FZ, UK
| | - Emmanuelle Bitoun
- The Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, UK.,Department of Statistics, University of Oxford, 24-29 St Giles', Oxford, OX1 3LB, UK
| | - Nicolas Altemose
- The Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, UK.,Department of Statistics, University of Oxford, 24-29 St Giles', Oxford, OX1 3LB, UK.,Department of Bioengineering, Stanley Hall, University of California, Berkeley, CA, 94720, USA
| | - Robert W Davies
- The Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, UK.,Department of Statistics, University of Oxford, 24-29 St Giles', Oxford, OX1 3LB, UK
| | - Benjamin Davies
- The Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, UK
| | - Simon R Myers
- The Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, UK. .,Department of Statistics, University of Oxford, 24-29 St Giles', Oxford, OX1 3LB, UK.
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25
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Schwarz T, Striedner Y, Horner A, Haase K, Kemptner J, Zeppezauer N, Hermann P, Tiemann-Boege I. PRDM9 forms a trimer by interactions within the zinc finger array. Life Sci Alliance 2019; 2:2/4/e201800291. [PMID: 31308055 PMCID: PMC6643046 DOI: 10.26508/lsa.201800291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 11/24/2022] Open
Abstract
PRDM9 forms a trimer as a soluble protein and in complex with DNA mediated by the ZnF domain. Five ZnFs are already sufficient for multimerization and only one DNA molecule is complexed in the trimer. PRDM9 is a trans-acting factor directing meiotic recombination to specific DNA-binding sites by its zinc finger (ZnF) array. It was suggested that PRDM9 is a multimer; however, we do not know the stoichiometry or the components inducing PRDM9 multimerization. In this work, we used in vitro binding studies and characterized with electrophoretic mobility shift assays, mass spectrometry, and fluorescence correlation spectroscopy the stoichiometry of the PRDM9 multimer of two different murine PRDM9 alleles carrying different tags and domains produced with different expression systems. Based on the migration distance of the PRDM9–DNA complex, we show that PRDM9 forms a trimer. Moreover, this stoichiometry is adapted already by the free, soluble protein with little exchange between protein monomers. The variable ZnF array of PRDM9 is sufficient for multimerization, and at least five ZnFs form already a functional trimer. Finally, we also show that only one ZnF array within the PRDM9 oligomer binds to the DNA, whereas the remaining two ZnF arrays likely maintain the trimer by ZnF–ZnF interactions.
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Affiliation(s)
- Theresa Schwarz
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Yasmin Striedner
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Andreas Horner
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Karin Haase
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Jasmin Kemptner
- Red Cross Blood Transfusion Center Upper Austria, MedCampus II, Johannes Kepler University, Linz, Austria
| | | | - Philipp Hermann
- Institute of Applied Statistics, Johannes Kepler University, Linz, Austria
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26
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Ostrander EA, Wang GD, Larson G, vonHoldt BM, Davis BW, Jagannathan V, Hitte C, Wayne RK, Zhang YP. Dog10K: an international sequencing effort to advance studies of canine domestication, phenotypes and health. Natl Sci Rev 2019; 6:810-824. [PMID: 31598383 PMCID: PMC6776107 DOI: 10.1093/nsr/nwz049] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/14/2019] [Accepted: 04/09/2019] [Indexed: 12/18/2022] Open
Abstract
Dogs are the most phenotypically diverse mammalian species, and they possess more known heritable disorders than any other non-human mammal. Efforts to catalog and characterize genetic variation across well-chosen populations of canines are necessary to advance our understanding of their evolutionary history and genetic architecture. To date, no organized effort has been undertaken to sequence the world's canid populations. The Dog10K Consortium (http://www.dog10kgenomes.org) is an international collaboration of researchers from across the globe who will generate 20× whole genomes from 10 000 canids in 5 years. This effort will capture the genetic diversity that underlies the phenotypic and geographical variability of modern canids worldwide. Breeds, village dogs, niche populations and extended pedigrees are currently being sequenced, and de novo assemblies of multiple canids are being constructed. This unprecedented dataset will address the genetic underpinnings of domestication, breed formation, aging, behavior and morphological variation. More generally, this effort will advance our understanding of human and canine health.
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Affiliation(s)
- Elaine A Ostrander
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Guo-Dong Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Greger Larson
- Palaeogenomics and Bio-Archaeology Research Network, School of Archaeology, University of Oxford, Oxford OX1 3TG, UK
| | - Bridgett M vonHoldt
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544-1014, USA
| | - Brian W Davis
- College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77840, USA
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern CH-3001, Switzerland
| | | | - Robert K Wayne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
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27
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Mihola O, Pratto F, Brick K, Linhartova E, Kobets T, Flachs P, Baker CL, Sedlacek R, Paigen K, Petkov PM, Camerini-Otero RD, Trachtulec Z. Histone methyltransferase PRDM9 is not essential for meiosis in male mice. Genome Res 2019; 29:1078-1086. [PMID: 31186301 PMCID: PMC6633264 DOI: 10.1101/gr.244426.118] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 06/07/2019] [Indexed: 01/03/2023]
Abstract
A hallmark of meiosis is the rearrangement of parental alleles to ensure genetic diversity in the gametes. These chromosome rearrangements are mediated by the repair of programmed DNA double-strand breaks (DSBs) as genetic crossovers between parental homologs. In mice, humans, and many other mammals, meiotic DSBs occur primarily at hotspots, determined by sequence-specific binding of the PRDM9 protein. Without PRDM9, meiotic DSBs occur near gene promoters and other functional sites. Studies in a limited number of mouse strains showed that functional PRDM9 is required to complete meiosis, but despite its apparent importance, Prdm9 has been repeatedly lost across many animal lineages. Both the reason for mouse sterility in the absence of PRDM9 and the mechanism by which Prdm9 can be lost remain unclear. Here, we explore whether mice can tolerate the loss of Prdm9 By generating Prdm9 functional knockouts in an array of genetic backgrounds, we observe a wide range of fertility phenotypes and ultimately demonstrate that PRDM9 is not required for completion of male meiosis. Although DSBs still form at a common subset of functional sites in all mice lacking PRDM9, meiotic outcomes differ substantially. We speculate that DSBs at functional sites are difficult to repair as a crossover and that by increasing the efficiency of crossover formation at these sites, genetic modifiers of recombination rates can allow for meiotic progression. This model implies that species with a sufficiently high recombination rate may lose Prdm9 yet remain fertile.
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Affiliation(s)
- Ondrej Mihola
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Florencia Pratto
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kevin Brick
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Eliska Linhartova
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Tatyana Kobets
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Petr Flachs
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Christopher L Baker
- Center for Genome Dynamics, The Jackson Laboratory, Bar Harbor, Maine 04609, USA
| | - Radislav Sedlacek
- Laboratory of Transgenic Models of Diseases and Czech Centre for Phenogenomics, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Kenneth Paigen
- Center for Genome Dynamics, The Jackson Laboratory, Bar Harbor, Maine 04609, USA
| | - Petko M Petkov
- Center for Genome Dynamics, The Jackson Laboratory, Bar Harbor, Maine 04609, USA
| | - R Daniel Camerini-Otero
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Zdenek Trachtulec
- Laboratory of Germ Cell Development, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
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28
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Jones JC, Wallberg A, Christmas MJ, Kapheim KM, Webster MT. Extreme Differences in Recombination Rate between the Genomes of a Solitary and a Social Bee. Mol Biol Evol 2019; 36:2277-2291. [DOI: 10.1093/molbev/msz130] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Abstract
Social insect genomes exhibit the highest rates of crossing over observed in plants and animals. The evolutionary causes of these extreme rates are unknown. Insight can be gained by comparing recombination rate variation across the genomes of related social and solitary insects. Here, we compare the genomic recombination landscape of the highly social honey bee, Apis mellifera, with the solitary alfalfa leafcutter bee, Megachile rotundata, by analyzing patterns of linkage disequilibrium in population-scale genome sequencing data. We infer that average recombination rates are extremely elevated in A. mellifera compared with M. rotundata. However, our results indicate that similar factors control the distribution of crossovers in the genomes of both species. Recombination rate is significantly reduced in coding regions in both species, with genes inferred to be germline methylated having particularly low rates. Genes with worker-biased patterns of expression in A. mellifera and their orthologs in M. rotundata have higher than average recombination rates in both species, suggesting that selection for higher diversity in genes involved in worker caste functions in social taxa is not the explanation for these elevated rates. Furthermore, we find no evidence that recombination has modulated the efficacy of selection among genes during bee evolution, which does not support the hypothesis that high recombination rates facilitated positive selection for new functions in social insects. Our results indicate that the evolution of sociality in insects likely entailed selection on modifiers that increased recombination rates genome wide, but that the genomic recombination landscape is determined by the same factors.
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Affiliation(s)
- Julia C Jones
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Andreas Wallberg
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Matthew J Christmas
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | | | - Matthew T Webster
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
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29
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Tian H, Billings T, Petkov PM. CXXC1 is not essential for normal DNA double-strand break formation and meiotic recombination in mouse. PLoS Genet 2018; 14:e1007657. [PMID: 30365547 PMCID: PMC6221362 DOI: 10.1371/journal.pgen.1007657] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/07/2018] [Accepted: 08/24/2018] [Indexed: 12/28/2022] Open
Abstract
In most mammals, including mice and humans, meiotic recombination is determined by the meiosis specific histone methytransferase PRDM9, which binds to specific DNA sequences and trimethylates histone 3 at lysine-4 and lysine-36 at the adjacent nucleosomes. These actions ensure successful DNA double strand break formation and repair that occur on the proteinaceous structure forming the chromosome axis. The process of hotspot association with the axis after their activation by PRDM9 is poorly understood. Previously, we and others have identified CXXC1, an ortholog of S. cerevisiae Spp1 in mammals, as a PRDM9 interactor. In yeast, Spp1 is a histone methyl reader that links H3K4me3 sites with the recombination machinery, promoting DSB formation. Here, we investigated whether CXXC1 has a similar function in mouse meiosis. We created two Cxxc1 conditional knockout mouse models to deplete CXXC1 generally in germ cells, and before the onset of meiosis. Surprisingly, male knockout mice were fertile, and the loss of CXXC1 in spermatocytes had no effect on PRDM9 hotspot trimethylation, double strand break formation or repair. Our results demonstrate that CXXC1 is not an essential link between PRDM9-activated recombination hotspot sites and DSB machinery and that the hotspot recognition pathway in mouse is independent of CXXC1. Meiotic recombination increases genetic diversity by ensuring novel combination of alleles passing correctly to the next generation. In most mammals, the meiotic recombination sites are determined by histone methyltransferase PRDM9. These sites are proposed to become associated with the chromosome axis with the participation of additional proteins and undergo double strand breaks, which are repaired by homologous recombination. In budding yeast, Spp1 (ortholog of CXXC1) binds to methylated H3K4 and connects these sites with the chromosome axis promoting DSB formation. However, our data suggest that even though CXXC1 interacts with PRDM9 in male germ cells, it does not play a crucial role in mouse meiotic recombination. These results indicate that, unlike in yeast, a recombination initiation pathway that includes CXXC1 could only serve as a non-essential pathway in mouse meiosis.
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Affiliation(s)
- Hui Tian
- The Jackson Laboratory, Bar Harbor, ME 04609, United States of America
| | - Timothy Billings
- The Jackson Laboratory, Bar Harbor, ME 04609, United States of America
| | - Petko M. Petkov
- The Jackson Laboratory, Bar Harbor, ME 04609, United States of America
- * E-mail:
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30
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Abstract
During meiosis, maternal and paternal chromosomes undergo exchanges by homologous recombination. This is essential for fertility and contributes to genome evolution. In many eukaryotes, sites of meiotic recombination, also called hotspots, are regions of accessible chromatin, but in many vertebrates, their location follows a distinct pattern and is specified by PR domain-containing protein 9 (PRDM9). The specification of meiotic recombination hotspots is achieved by the different activities of PRDM9: DNA binding, histone methyltransferase, and interaction with other proteins. Remarkably, PRDM9 activity leads to the erosion of its own binding sites and the rapid evolution of its DNA-binding domain. PRDM9 may also contribute to reproductive isolation, as it is involved in hybrid sterility potentially due to a reduction of its activity in specific heterozygous contexts.
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Affiliation(s)
- Corinne Grey
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
| | - Frédéric Baudat
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
| | - Bernard de Massy
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
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31
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Lukaszewicz A, Lange J, Keeney S, Jasin M. Control of meiotic double-strand-break formation by ATM: local and global views. Cell Cycle 2018; 17:1155-1172. [PMID: 29963942 PMCID: PMC6110601 DOI: 10.1080/15384101.2018.1464847] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/19/2018] [Accepted: 04/08/2018] [Indexed: 10/28/2022] Open
Abstract
DNA double-strand breaks (DSBs) generated by the SPO11 protein initiate meiotic recombination, an essential process for successful chromosome segregation during gametogenesis. The activity of SPO11 is controlled by multiple factors and regulatory mechanisms, such that the number of DSBs is limited and DSBs form at distinct positions in the genome and at the right time. Loss of this control can affect genome integrity or cause meiotic arrest by mechanisms that are not fully understood. Here we focus on the DSB-responsive kinase ATM and its functions in regulating meiotic DSB numbers and distribution. We review the recently discovered roles of ATM in this context, discuss their evolutionary conservation, and examine future research perspectives.
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Affiliation(s)
- Agnieszka Lukaszewicz
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Julian Lange
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Scott Keeney
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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32
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Campbell CR, Poelstra JW, Yoder AD. What is Speciation Genomics? The roles of ecology, gene flow, and genomic architecture in the formation of species. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly063] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - J W Poelstra
- Department of Biology, Duke University, Durham, NC, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC, USA
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33
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Tiemann-Boege I, Schwarz T, Striedner Y, Heissl A. The consequences of sequence erosion in the evolution of recombination hotspots. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0462. [PMID: 29109225 PMCID: PMC5698624 DOI: 10.1098/rstb.2016.0462] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2017] [Indexed: 12/18/2022] Open
Abstract
Meiosis is initiated by a double-strand break (DSB) introduced in the DNA by a highly controlled process that is repaired by recombination. In many organisms, recombination occurs at specific and narrow regions of the genome, known as recombination hotspots, which overlap with regions enriched for DSBs. In recent years, it has been demonstrated that conversions and mutations resulting from the repair of DSBs lead to a rapid sequence evolution at recombination hotspots eroding target sites for DSBs. We still do not fully understand the effect of this erosion in the recombination activity, but evidence has shown that the binding of trans-acting factors like PRDM9 is affected. PRDM9 is a meiosis-specific, multi-domain protein that recognizes DNA target motifs by its zinc finger domain and directs DSBs to these target sites. Here we discuss the changes in affinity of PRDM9 to eroded recognition sequences, and explain how these changes in affinity of PRDM9 can affect recombination, leading sometimes to sterility in the context of hybrid crosses. We also present experimental data showing that DNA methylation reduces PRDM9 binding in vitro. Finally, we discuss PRDM9-independent hotspots, posing the question how these hotspots evolve and change with sequence erosion. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
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Affiliation(s)
- Irene Tiemann-Boege
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Theresa Schwarz
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Yasmin Striedner
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Angelika Heissl
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
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34
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Latrille T, Duret L, Lartillot N. The Red Queen model of recombination hot-spot evolution: a theoretical investigation. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0463. [PMID: 29109226 PMCID: PMC5698625 DOI: 10.1098/rstb.2016.0463] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2017] [Indexed: 11/12/2022] Open
Abstract
In humans and many other species, recombination events cluster in narrow and short-lived hot spots distributed across the genome, whose location is determined by the Zn-finger protein PRDM9. To explain these fast evolutionary dynamics, an intra-genomic Red Queen model has been proposed, based on the interplay between two antagonistic forces: biased gene conversion, mediated by double-strand breaks, resulting in hot-spot extinction, followed by positive selection favouring new PRDM9 alleles recognizing new sequence motifs. Thus far, however, this Red Queen model has not been formalized as a quantitative population-genetic model, fully accounting for the intricate interplay between biased gene conversion, mutation, selection, demography and genetic diversity at the PRDM9 locus. Here, we explore the population genetics of the Red Queen model of recombination. A Wright–Fisher simulator was implemented, allowing exploration of the behaviour of the model (mean equilibrium recombination rate, diversity at the PRDM9 locus or turnover rate) as a function of the parameters (effective population size, mutation and erosion rates). In a second step, analytical results based on self-consistent mean-field approximations were derived, reproducing the scaling relations observed in the simulations. Empirical fit of the model to current data from the mouse suggests both a high mutation rate at PRDM9 and strong biased gene conversion on its targets. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
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Affiliation(s)
- Thibault Latrille
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
| | - Laurent Duret
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
| | - Nicolas Lartillot
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
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35
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Stapley J, Feulner PGD, Johnston SE, Santure AW, Smadja CM. Variation in recombination frequency and distribution across eukaryotes: patterns and processes. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0455. [PMID: 29109219 PMCID: PMC5698618 DOI: 10.1098/rstb.2016.0455] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2017] [Indexed: 01/04/2023] Open
Abstract
Recombination, the exchange of DNA between maternal and paternal chromosomes during meiosis, is an essential feature of sexual reproduction in nearly all multicellular organisms. While the role of recombination in the evolution of sex has received theoretical and empirical attention, less is known about how recombination rate itself evolves and what influence this has on evolutionary processes within sexually reproducing organisms. Here, we explore the patterns of, and processes governing recombination in eukaryotes. We summarize patterns of variation, integrating current knowledge with an analysis of linkage map data in 353 organisms. We then discuss proximate and ultimate processes governing recombination rate variation and consider how these influence evolutionary processes. Genome-wide recombination rates (cM/Mb) can vary more than tenfold across eukaryotes, and there is large variation in the distribution of recombination events across closely related taxa, populations and individuals. We discuss how variation in rate and distribution relates to genome architecture, genetic and epigenetic mechanisms, sex, environmental perturbations and variable selective pressures. There has been great progress in determining the molecular mechanisms governing recombination, and with the continued development of new modelling and empirical approaches, there is now also great opportunity to further our understanding of how and why recombination rate varies.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
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Affiliation(s)
- Jessica Stapley
- Centre for Adaptation to a Changing Environment, IBZ, ETH Zürich, 8092 Zürich, Switzerland
| | - Philine G D Feulner
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland.,Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
| | - Susan E Johnston
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JY, UK
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Carole M Smadja
- Institut des Sciences de l'Evolution UMR 5554, CNRS, IRD, EPHE, Université de Montpellier, 3095 Montpellier cedex 05, France
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36
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Kent TV, Uzunović J, Wright SI. Coevolution between transposable elements and recombination. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0458. [PMID: 29109221 DOI: 10.1098/rstb.2016.0458] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2017] [Indexed: 12/24/2022] Open
Abstract
One of the most striking patterns of genome structure is the tight, typically negative, association between transposable elements (TEs) and meiotic recombination rates. While this is a highly recurring feature of eukaryotic genomes, the mechanisms driving correlations between TEs and recombination remain poorly understood, and distinguishing cause versus effect is challenging. Here, we review the evidence for a relation between TEs and recombination, and discuss the underlying evolutionary forces. Evidence to date suggests that overall TE densities correlate negatively with recombination, but the strength of this correlation varies across element types, and the pattern can be reversed. Results suggest that heterogeneity in the strength of selection against ectopic recombination and gene disruption can drive TE accumulation in regions of low recombination, but there is also strong evidence that the regulation of TEs can influence local recombination rates. We hypothesize that TE insertion polymorphism may be important in driving within-species variation in recombination rates in surrounding genomic regions. Furthermore, the interaction between TEs and recombination may create positive feedback, whereby TE accumulation in non-recombining regions contributes to the spread of recombination suppression. Further investigation of the coevolution between recombination and TEs has important implications for our understanding of the evolution of recombination rates and genome structure.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
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Affiliation(s)
- Tyler V Kent
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, Ontario, Canada M5S3B2
| | - Jasmina Uzunović
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, Ontario, Canada M5S3B2
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, Ontario, Canada M5S3B2
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37
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Zhou Y, Shen B, Jiang J, Padhi A, Park KE, Oswalt A, Sattler CG, Telugu BP, Chen H, Cole JB, Liu GE, Ma L. Construction of PRDM9 allele-specific recombination maps in cattle using large-scale pedigree analysis and genome-wide single sperm genomics. DNA Res 2018; 25:183-194. [PMID: 29186399 PMCID: PMC5909443 DOI: 10.1093/dnares/dsx048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/09/2017] [Indexed: 11/23/2022] Open
Abstract
PRDM9 contributes to hybrid sterility and species evolution. However, its role is to be confirmed in cattle, a major domesticated livestock species. We previously found an association near PRDM9 with cattle recombination features, but the causative variants are still unknown. Using millions of genotyped cattle with pedigree information, we characterized five PRDM9 alleles and generated allele-specific recombination maps. By examining allele-specific recombination patterns, we observed the impact of PRDM9 on global distribution of recombination, especially in the two ends of chromosomes. We also showed strong associations between recombination hotspot regions and functional mutations within PRDM9 zinc finger domain. More importantly, we found one allele of PRDM9 to be very different from others in both protein composition and recombination landscape, indicating the causative role of this allele on the association between PRDM9 and cattle recombination. When comparing recombination maps from sperm and pedigree data, we observed similar genome-wide recombination patterns, validating the quality of pedigree-based results. Collectively, these evidence supported PRDM9 alleles as causal variants for the reported association with cattle recombination. Our study comprehensively surveyed the bovine PRDM9 alleles, generated allele-specific recombination maps, and expanded our understanding of the role of PRDM9 on genome distribution of recombination.
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Affiliation(s)
- Yang Zhou
- Animal Genomics and Improvement Laboratory, BARC, USDA-ARS, Beltsville, MD 20705, USA
- Shaanxi Key Laboratory of Agricultural Molecular Biology, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Education Ministry of China, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Botong Shen
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Jicai Jiang
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Abinash Padhi
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Ki-Eun Park
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Adam Oswalt
- Select Sires Inc. 11740 U.S. 42 North, Plain City, Ohio 43064, USA
| | | | - Bhanu P Telugu
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Hong Chen
- Shaanxi Key Laboratory of Agricultural Molecular Biology, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - John B Cole
- Animal Genomics and Improvement Laboratory, BARC, USDA-ARS, Beltsville, MD 20705, USA
| | - George E Liu
- Animal Genomics and Improvement Laboratory, BARC, USDA-ARS, Beltsville, MD 20705, USA
| | - Li Ma
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
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38
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Dapper AL, Payseur BA. Effects of Demographic History on the Detection of Recombination Hotspots from Linkage Disequilibrium. Mol Biol Evol 2018; 35:335-353. [PMID: 29045724 PMCID: PMC5850621 DOI: 10.1093/molbev/msx272] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In some species, meiotic recombination is concentrated in small genomic regions. These "recombination hotspots" leave signatures in fine-scale patterns of linkage disequilibrium, raising the prospect that the genomic landscape of hotspots can be characterized from sequence variation. This approach has led to the inference that hotspots evolve rapidly in some species, but are conserved in others. Historic demographic events, such as population bottlenecks, are known to affect patterns of linkage disequilibrium across the genome, violating population genetic assumptions of this approach. Although such events are prevalent, demographic history is generally ignored when making inferences about the evolution of recombination hotspots. To determine the effect of demography on the detection of recombination hotspots, we use the coalescent to simulate haplotypes with a known recombination landscape. We measure the ability of popular linkage disequilibrium-based programs to detect hotspots across a range of demographic histories, including population bottlenecks, hidden population structure, population expansions, and population contractions. We find that demographic events have the potential to greatly reduce the power and increase the false positive rate of hotspot discovery. Neither the power nor the false positive rate of hotspot detection can be predicted without also knowing the demographic history of the sample. Our results suggest that ignoring demographic history likely overestimates the power to detect hotspots and therefore underestimates the degree of hotspot sharing between species. We suggest strategies for incorporating demographic history into population genetic inferences about recombination hotspots.
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Affiliation(s)
- Amy L Dapper
- Laboratory of Genetics, University of Wisconsin, Madison, WI
| | - Bret A Payseur
- Laboratory of Genetics, University of Wisconsin, Madison, WI
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39
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Paigen K, Petkov PM. PRDM9 and Its Role in Genetic Recombination. Trends Genet 2018; 34:291-300. [PMID: 29366606 DOI: 10.1016/j.tig.2017.12.017] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 12/14/2017] [Accepted: 12/20/2017] [Indexed: 12/22/2022]
Abstract
PRDM9 is a zinc finger protein that binds DNA at specific locations in the genome where it trimethylates histone H3 at lysines 4 and 36 at surrounding nucleosomes. During meiosis in many species, including humans and mice where PRDM9 has been most intensely studied, these actions determine the location of recombination hotspots, where genetic recombination occurs. In addition, PRDM9 facilitates the association of hotspots with the chromosome axis, the site of the programmed DNA double-strand breaks (DSBs) that give rise to genetic exchange between chromosomes. In the absence of PRDM9 DSBs are not properly repaired. Collectively, these actions determine patterns of genetic linkage and the possibilities for chromosome reorganization over successive generations.
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40
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Haag CR, Theodosiou L, Zahab R, Lenormand T. Low recombination rates in sexual species and sex-asex transitions. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160461. [PMID: 29109224 PMCID: PMC5698623 DOI: 10.1098/rstb.2016.0461] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2017] [Indexed: 12/11/2022] Open
Abstract
In most sexual, diploid eukaryotes, at least one crossover occurs between each pair of homologous chromosomes during meiosis, presumably in order to ensure proper segregation. Well-known exceptions to this rule are species in which one sex does not recombine and specific chromosomes lacking crossover. We review other possible exceptions, including species with chromosome maps of less than 50 cM in one or both sexes. We discuss the idea that low recombination rates may favour sex-asex transitions, or, alternatively may be a consequence of it. We then show that a yet undescribed species of brine shrimp Artemia from Kazakhstan (A sp. Kazakhstan), the closest known relative of the asexual Artemia parthenogenetica, has one of the shortest genetic linkage maps known. Based on a family of 42 individuals and 589 RAD markers, we find that many linkage groups are considerably shorter than 50 cM, suggesting either no obligate crossover or crossovers concentrated at terminal positions with little effect on recombination. We contrast these findings with the published map of the more distantly related sexual congener, A. franciscana, and conclude that the study of recombination in non-model systems is important to understand the evolutionary causes and consequences of recombination.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
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Affiliation(s)
- Christoph R Haag
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE)-Unité Mixte de Recherche 5175, Centre National de la Recherche Scientifique (CNRS), Université de Montpellier-Université Paul-Valéry Montpellier-École Pratique des Hautes Études, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Loukas Theodosiou
- Research Group for Community Dynamics, Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, 24306 Plön, Germany
| | - Roula Zahab
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE)-Unité Mixte de Recherche 5175, Centre National de la Recherche Scientifique (CNRS), Université de Montpellier-Université Paul-Valéry Montpellier-École Pratique des Hautes Études, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Thomas Lenormand
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE)-Unité Mixte de Recherche 5175, Centre National de la Recherche Scientifique (CNRS), Université de Montpellier-Université Paul-Valéry Montpellier-École Pratique des Hautes Études, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
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41
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Stevison LS, Sefick S, Rushton C, Graze RM. Recombination rate plasticity: revealing mechanisms by design. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160459. [PMID: 29109222 PMCID: PMC5698621 DOI: 10.1098/rstb.2016.0459] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2017] [Indexed: 12/13/2022] Open
Abstract
For over a century, scientists have known that meiotic recombination rates can vary considerably among individuals, and that environmental conditions can modify recombination rates relative to the background. A variety of external and intrinsic factors such as temperature, age, sex and starvation can elicit 'plastic' responses in recombination rate. The influence of recombination rate plasticity on genetic diversity of the next generation has interesting and important implications for how populations evolve. Further, many questions remain regarding the mechanisms and molecular processes that contribute to recombination rate plasticity. Here, we review 100 years of experimental work on recombination rate plasticity conducted in Drosophila melanogaster We categorize this work into four major classes of experimental designs, which we describe via classic studies in D. melanogaster Based on these studies, we highlight molecular mechanisms that are supported by experimental results and relate these findings to studies in other systems. We synthesize lessons learned from this model system into experimental guidelines for using recent advances in genotyping technologies, to study recombination rate plasticity in non-model organisms. Specifically, we recommend (1) using fine-scale genome-wide markers, (2) collecting time-course data, (3) including crossover distribution measurements, and (4) using mixed effects models to analyse results. To illustrate this approach, we present an application adhering to these guidelines from empirical work we conducted in Drosophila pseudoobscuraThis article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
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Affiliation(s)
- Laurie S Stevison
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Stephen Sefick
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Chase Rushton
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Rita M Graze
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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42
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Yamada S, Kim S, Tischfield SE, Jasin M, Lange J, Keeney S. Genomic and chromatin features shaping meiotic double-strand break formation and repair in mice. Cell Cycle 2017; 16:1870-1884. [PMID: 28820351 PMCID: PMC5638367 DOI: 10.1080/15384101.2017.1361065] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/27/2017] [Accepted: 07/25/2017] [Indexed: 11/12/2022] Open
Abstract
The SPO11-generated DNA double-strand breaks (DSBs) that initiate meiotic recombination occur non-randomly across genomes, but mechanisms shaping their distribution and repair remain incompletely understood. Here, we expand on recent studies of nucleotide-resolution DSB maps in mouse spermatocytes. We find that trimethylation of histone H3 lysine 36 around DSB hotspots is highly correlated, both spatially and quantitatively, with trimethylation of H3 lysine 4, consistent with coordinated formation and action of both PRDM9-dependent histone modifications. In contrast, the DSB-responsive kinase ATM contributes independently of PRDM9 to controlling hotspot activity, and combined action of ATM and PRDM9 can explain nearly two-thirds of the variation in DSB frequency between hotspots. DSBs were modestly underrepresented in most repetitive sequences such as segmental duplications and transposons. Nonetheless, numerous DSBs form within repetitive sequences in each meiosis and some classes of repeats are preferentially targeted. Implications of these findings are discussed for evolution of PRDM9 and its role in hybrid strain sterility in mice. Finally, we document the relationship between mouse strain-specific DNA sequence variants within PRDM9 recognition motifs and attendant differences in recombination outcomes. Our results provide further insights into the complex web of factors that influence meiotic recombination patterns.
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Affiliation(s)
- Shintaro Yamada
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Seoyoung Kim
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Sam E. Tischfield
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Tri-Institutional Training Program in Computational Biology and Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Julian Lange
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Scott Keeney
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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43
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Dion-Côté AM, Barbash DA. Beyond speciation genes: an overview of genome stability in evolution and speciation. Curr Opin Genet Dev 2017; 47:17-23. [PMID: 28830007 DOI: 10.1016/j.gde.2017.07.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/17/2017] [Accepted: 07/28/2017] [Indexed: 01/03/2023]
Abstract
Genome stability ensures individual fitness and reliable transmission of genetic information. Hybridization between diverging lineages can trigger genome instability, highlighting its potential role in post-zygotic reproductive isolation. We argue that genome instability is not merely one of several types of hybrid incompatibility, but rather that genome stability is one of the very first and most fundamental traits that can break down when two diverged genomes are combined. Future work will reveal how frequent and predictable genome instability is in hybrids, how it affects hybrid fitness, and whether it is a direct cause or consequence of speciation.
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Affiliation(s)
- Anne-Marie Dion-Côté
- Department of Molecular Biology and Genetics, Cornell University, 526 Campus Road, Ithaca, NY 14853, United States
| | - Daniel A Barbash
- Department of Molecular Biology and Genetics, Cornell University, 526 Campus Road, Ithaca, NY 14853, United States.
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44
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Abstract
The ways in which recombination sites are determined during meiosis are becoming clearer following a phylogenomic analysis for 225 different species.
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Affiliation(s)
- Julie Clément
- Institut de Génétique Humaine, CNRS-Université de Montpellier, Montpellier, France
| | - Bernard de Massy
- Institut de Génétique Humaine, CNRS-Université de Montpellier, Montpellier, France
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45
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Structural Variation Shapes the Landscape of Recombination in Mouse. Genetics 2017; 206:603-619. [PMID: 28592499 DOI: 10.1534/genetics.116.197988] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/13/2017] [Indexed: 01/02/2023] Open
Abstract
Meiotic recombination is an essential feature of sexual reproduction that ensures faithful segregation of chromosomes and redistributes genetic variants in populations. Multiparent populations such as the Diversity Outbred (DO) mouse stock accumulate large numbers of crossover (CO) events between founder haplotypes, and thus present a unique opportunity to study the role of genetic variation in shaping the recombination landscape. We obtained high-density genotype data from [Formula: see text] DO mice, and localized 2.2 million CO events to intervals with a median size of 28 kb. The resulting sex-averaged genetic map of the DO population is highly concordant with large-scale (order 10 Mb) features of previously reported genetic maps for mouse. To examine fine-scale (order 10 kb) patterns of recombination in the DO, we overlaid putative recombination hotspots onto our CO intervals. We found that CO intervals are enriched in hotspots compared to the genomic background. However, as many as [Formula: see text] of CO intervals do not overlap any putative hotspots, suggesting that our understanding of hotspots is incomplete. We also identified coldspots encompassing 329 Mb, or [Formula: see text] of observable genome, in which there is little or no recombination. In contrast to hotspots, which are a few kilobases in size, and widely scattered throughout the genome, coldspots have a median size of 2.1 Mb and are spatially clustered. Coldspots are strongly associated with copy-number variant (CNV) regions, especially multi-allelic clusters, identified from whole-genome sequencing of 228 DO mice. Genes in these regions have reduced expression, and epigenetic features of closed chromatin in male germ cells, which suggests that CNVs may repress recombination by altering chromatin structure in meiosis. Our findings demonstrate how multiparent populations, by bridging the gap between large-scale and fine-scale genetic mapping, can reveal new features of the recombination landscape.
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46
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Kawakami T, Mugal CF, Suh A, Nater A, Burri R, Smeds L, Ellegren H. Whole-genome patterns of linkage disequilibrium across flycatcher populations clarify the causes and consequences of fine-scale recombination rate variation in birds. Mol Ecol 2017; 26:4158-4172. [DOI: 10.1111/mec.14197] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/02/2017] [Accepted: 05/15/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Takeshi Kawakami
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
| | - Carina F. Mugal
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
| | - Alexander Suh
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
| | - Alexander Nater
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Zürich Switzerland
| | - Reto Burri
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
- Department of Population Ecology; Friedrich Schiller University Jena; Jena Germany
| | - Linnéa Smeds
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology; Evolutionary Biology Centre (EBC); Uppsala University; Uppsala Sweden
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47
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Abstract
Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data.
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48
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Grey C, Clément JAJ, Buard J, Leblanc B, Gut I, Gut M, Duret L, de Massy B. In vivo binding of PRDM9 reveals interactions with noncanonical genomic sites. Genome Res 2017; 27:580-590. [PMID: 28336543 PMCID: PMC5378176 DOI: 10.1101/gr.217240.116] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 02/23/2017] [Indexed: 02/02/2023]
Abstract
In mouse and human meiosis, DNA double-strand breaks (DSBs) initiate homologous recombination and occur at specific sites called hotspots. The localization of these sites is determined by the sequence-specific DNA binding domain of the PRDM9 histone methyl transferase. Here, we performed an extensive analysis of PRDM9 binding in mouse spermatocytes. Unexpectedly, we identified a noncanonical recruitment of PRDM9 to sites that lack recombination activity and the PRDM9 binding consensus motif. These sites include gene promoters, where PRDM9 is recruited in a DSB-dependent manner. Another subset reveals DSB-independent interactions between PRDM9 and genomic sites, such as the binding sites for the insulator protein CTCF. We propose that these DSB-independent sites result from interactions between hotspot-bound PRDM9 and genomic sequences located on the chromosome axis.
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Affiliation(s)
- Corinne Grey
- Institut de Génétique Humaine UMR9002 CNRS-Université de Montpellier, 34396 Montpellier Cedex 05, France
| | - Julie A J Clément
- Institut de Génétique Humaine UMR9002 CNRS-Université de Montpellier, 34396 Montpellier Cedex 05, France
| | - Jérôme Buard
- Institut de Génétique Humaine UMR9002 CNRS-Université de Montpellier, 34396 Montpellier Cedex 05, France
| | - Benjamin Leblanc
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ivo Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Marta Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Laurent Duret
- Université de Lyon, Université Claude Bernard, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69100, Villeurbanne, France
| | - Bernard de Massy
- Institut de Génétique Humaine UMR9002 CNRS-Université de Montpellier, 34396 Montpellier Cedex 05, France
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49
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VanBelzen DJ, Malik AS, Henthorn PS, Kornegay JN, Stedman HH. Mechanism of Deletion Removing All Dystrophin Exons in a Canine Model for DMD Implicates Concerted Evolution of X Chromosome Pseudogenes. Mol Ther Methods Clin Dev 2017; 4:62-71. [PMID: 28344992 PMCID: PMC5363321 DOI: 10.1016/j.omtm.2016.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/07/2016] [Indexed: 01/19/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a lethal, X-linked, muscle-wasting disorder caused by mutations in the large, 2.4-Mb dystrophin gene. The majority of DMD-causing mutations are sporadic, multi-exon, frameshifting deletions, with the potential for variable immunological tolerance to the dystrophin protein from patient to patient. While systemic gene therapy holds promise in the treatment of DMD, immune responses to vectors and transgenes must first be rigorously evaluated in informative preclinical models to ensure patient safety. A widely used canine model for DMD, golden retriever muscular dystrophy, expresses detectable amounts of near full-length dystrophin due to alternative splicing around an intronic point mutation, thereby confounding the interpretation of immune responses to dystrophin-derived gene therapies. Here we characterize a naturally occurring deletion in a dystrophin-null canine, the German shorthaired pointer. The deletion spans 5.6 Mb of the X chromosome and encompasses all coding exons of the DMD and TMEM47 genes. The sequences surrounding the deletion breakpoints are virtually identical, suggesting that the deletion occurred through a homologous recombination event. Interestingly, the deletion breakpoints are within loci that are syntenically conserved among mammals, yet the high homology among this subset of ferritin-like loci is unique to the canine genome, suggesting lineage-specific concerted evolution of these atypical sequence elements.
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Affiliation(s)
- D. Jake VanBelzen
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alock S. Malik
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paula S. Henthorn
- Section of Medical Genetics, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA
| | - Joe N. Kornegay
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA
| | - Hansell H. Stedman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Corporal Michael Crescenz Veterans Administration Medical Center, Philadelphia, PA 19104, USA
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50
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Padhi A, Shen B, Jiang J, Zhou Y, Liu GE, Ma L. Ruminant-specific multiple duplication events of PRDM9 before speciation. BMC Evol Biol 2017; 17:79. [PMID: 28292260 PMCID: PMC5351255 DOI: 10.1186/s12862-017-0892-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 01/26/2017] [Indexed: 11/30/2022] Open
Abstract
Background Understanding the genetic and evolutionary mechanisms of speciation genes in sexually reproducing organisms would provide important insights into mammalian reproduction and fitness. PRDM9, a widely known speciation gene, has recently gained attention for its important role in meiotic recombination and hybrid incompatibility. Despite the fact that PRDM9 is a key regulator of recombination and plays a dominant role in hybrid incompatibility, little is known about the underlying genetic and evolutionary mechanisms that generated multiple copies of PRDM9 in many metazoan lineages. Results The present study reports (1) evidence of ruminant-specific multiple gene duplication events, which likely have had occurred after the ancestral ruminant population diverged from its most recent common ancestor and before the ruminant speciation events, (2) presence of three copies of PRDM9, one copy (lineages I) in chromosome 1 (chr1) and two copies (lineages II & III) in chromosome X (chrX), thus indicating the possibility of ancient inter- and intra-chromosomal unequal crossing over and gene conversion events, (3) while lineages I and II are characterized by the presence of variable tandemly repeated C2H2 zinc finger (ZF) arrays, lineage III lost these arrays, and (4) C2H2 ZFs of lineages I and II, particularly the amino acid residues located at positions −1, 3, and 6 have evolved under strong positive selection. Conclusions Our results demonstrated two gene duplication events of PRDM9 in ruminants: an inter-chromosomal duplication that occurred between chr1 and chrX, and an intra-chromosomal X-linked duplication, which resulted in two additional copies of PRDM9 in ruminants. The observation of such duplication between chrX and chr1 is rare and may possibly have happened due to unequal crossing-over millions of years ago when sex chromosomes were independently derived from a pair of ancestral autosomes. Two copies (lineages I & II) are characterized by the presence of variable sized tandem-repeated C2H2 ZFs and evolved under strong positive selection and concerted evolution, supporting the notion of well-established Red Queen hypothesis. Collectively, gene duplication, concerted evolution, and positive selection are the likely driving forces for the expansion of ruminant PRDM9 sub-family. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0892-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Abinash Padhi
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, 20742, USA.
| | - Botong Shen
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, 20742, USA
| | - Jicai Jiang
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, 20742, USA
| | - Yang Zhou
- Animal Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD, 20705, USA.,College of Animal Science and Technology, Northwest A & F University, Shaanxi Key Laboratory of Agricultural Molecular Biology, Yangling, Shaanxi, 712100, China
| | - George E Liu
- Animal Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD, 20705, USA
| | - Li Ma
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, 20742, USA.
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