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Jonika MM, Wilhoit KT, Chin M, Arekere A, Blackmon H. Drift drives the evolution of chromosome number II: The impact of range size on genome evolution in Carnivora. J Hered 2024; 115:524-531. [PMID: 38712909 PMCID: PMC11334210 DOI: 10.1093/jhered/esae025] [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: 06/30/2023] [Revised: 01/03/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024] Open
Abstract
Chromosome number is a fundamental genomic trait that is often the first recorded characteristic of a genome. Across large clades, a common pattern emerges: many or even most lineages exhibit relative stasis, while a handful of lineages or species exhibit striking variation. Despite recent developments in comparative methods, most of this heterogeneity is still poorly understood. It is essential to understand why some lineages have rapid rates of chromosome number evolution, as it can impact a variety of other traits. Previous research suggests that biased female meiotic drive may shape rates of karyotype evolution in some mammals. However, Carnivora exhibits variation that this female meiotic drive model cannot explain. We hypothesize that variation in effective population size may underlie rate variation in Carnivora. To test this hypothesis, we estimated rates of fusions and fissions while accounting for range size, which we use as a proxy for effective population size. We reason fusions and fissions are deleterious or underdominant and that only in lineages with small range sizes will these changes be able to fix due to genetic drift. In this study, we find that the rates of fusions and fissions are elevated in taxa with small range sizes relative to those with large range sizes. Based on these findings, we conclude that 1) naturally occurring structural mutations that change chromosome number are underdominant or mildly deleterious, and 2) when population sizes are small, structural rearrangements may play an important role in speciation and reduction in gene flow among populations.
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Affiliation(s)
- Michelle M Jonika
- Department of Biology, Texas A&M University, College Station, TX, United States
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX, United States
| | - Kayla T Wilhoit
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Maximos Chin
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Abhimanyu Arekere
- Department of Biology, Texas A&M University, College Station, TX, United States
- Department of Biomedical Engineering, University of Texas, Austin, TX, United States
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, TX, United States
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX, United States
- Ecology and Evolutionary Biology Interdepartmental Program, Texas A&M University, College Station, TX, United States
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2
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Coelho MA, David-Palma M, Shea T, Bowers K, McGinley-Smith S, Mohammad AW, Gnirke A, Yurkov AM, Nowrousian M, Sun S, Cuomo CA, Heitman J. Comparative genomics of the closely related fungal genera Cryptococcus and Kwoniella reveals karyotype dynamics and suggests evolutionary mechanisms of pathogenesis. PLoS Biol 2024; 22:e3002682. [PMID: 38843310 PMCID: PMC11185503 DOI: 10.1371/journal.pbio.3002682] [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: 01/13/2024] [Revised: 06/18/2024] [Accepted: 05/17/2024] [Indexed: 06/19/2024] Open
Abstract
In exploring the evolutionary trajectories of both pathogenesis and karyotype dynamics in fungi, we conducted a large-scale comparative genomic analysis spanning the Cryptococcus genus, encompassing both global human fungal pathogens and nonpathogenic species, and related species from the sister genus Kwoniella. Chromosome-level genome assemblies were generated for multiple species, covering virtually all known diversity within these genera. Although Cryptococcus and Kwoniella have comparable genome sizes (about 19.2 and 22.9 Mb) and similar gene content, hinting at preadaptive pathogenic potential, our analysis found evidence of gene gain (via horizontal gene transfer) and gene loss in pathogenic Cryptococcus species, which might represent evolutionary signatures of pathogenic development. Genome analysis also revealed a significant variation in chromosome number and structure between the 2 genera. By combining synteny analysis and experimental centromere validation, we found that most Cryptococcus species have 14 chromosomes, whereas most Kwoniella species have fewer (11, 8, 5, or even as few as 3). Reduced chromosome number in Kwoniella is associated with formation of giant chromosomes (up to 18 Mb) through repeated chromosome fusion events, each marked by a pericentric inversion and centromere loss. While similar chromosome inversion-fusion patterns were observed in all Kwoniella species with fewer than 14 chromosomes, no such pattern was detected in Cryptococcus. Instead, Cryptococcus species with less than 14 chromosomes showed reductions primarily through rearrangements associated with the loss of repeat-rich centromeres. Additionally, Cryptococcus genomes exhibited frequent interchromosomal translocations, including intercentromeric recombination facilitated by transposons shared between centromeres. Overall, our findings advance our understanding of genetic changes possibly associated with pathogenicity in Cryptococcus and provide a foundation to elucidate mechanisms of centromere loss and chromosome fusion driving distinct karyotypes in closely related fungal species, including prominent global human pathogens.
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Affiliation(s)
- Marco A. Coelho
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Márcia David-Palma
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Terrance Shea
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Katharine Bowers
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Sage McGinley-Smith
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Arman W. Mohammad
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Andreas Gnirke
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Andrey M. Yurkov
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Minou Nowrousian
- Lehrstuhl für Molekulare und Zelluläre Botanik, Ruhr-Universität Bochum, Bochum, Germany
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Christina A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
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3
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Jin J, Zhan Z, Wei X, Pan Z, Zhao Y, Yu D, Zhang F. Genomic insights into the chromosomal elongation in a family of Collembola. Proc Biol Sci 2024; 291:20232937. [PMID: 38471545 DOI: 10.1098/rspb.2023.2937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Collembola is a highly diverse and abundant group of soil arthropods with chromosome numbers ranging from 5 to 11. Previous karyotype studies indicated that the Tomoceridae family possesses an exceptionally long chromosome. To better understand chromosome size evolution in Collembola, we obtained a chromosome-level genome of Yoshiicerus persimilis with a size of 334.44 Mb and BUSCO completeness of 97.0% (n = 1013). Both genomes of Y. persimilis and Tomocerus qinae (recently published) have an exceptionally large chromosome (ElChr greater than 100 Mb), accounting for nearly one-third of the genome. Comparative genomic analyses suggest that chromosomal elongation occurred independently in the two species approximately 10 million years ago, rather than in the ancestor of the Tomoceridae family. The ElChr elongation was caused by large tandem and segmental duplications, as well as transposon proliferation, with genes in these regions experiencing weaker purifying selection (higher dN/dS) than conserved regions. Moreover, inter-genomic synteny analyses indicated that chromosomal fission/fusion events played a crucial role in the evolution of chromosome numbers (ranging from 5 to 7) within Entomobryomorpha. This study provides a valuable resource for investigating the chromosome evolution of Collembola.
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Affiliation(s)
- Jianfeng Jin
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Zhihong Zhan
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Xiping Wei
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Zhixiang Pan
- School of Life Sciences, Taizhou University, Taizhou 318000, People's Republic of China
| | - Yuxin Zhao
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Daoyuan Yu
- Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Feng Zhang
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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4
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Coelho MA, David-Palma M, Shea T, Bowers K, McGinley-Smith S, Mohammad AW, Gnirke A, Yurkov AM, Nowrousian M, Sun S, Cuomo CA, Heitman J. Comparative genomics of Cryptococcus and Kwoniella reveals pathogenesis evolution and contrasting karyotype dynamics via intercentromeric recombination or chromosome fusion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.27.573464. [PMID: 38234769 PMCID: PMC10793447 DOI: 10.1101/2023.12.27.573464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
A large-scale comparative genomic analysis was conducted for the global human fungal pathogens within the Cryptococcus genus, compared to non-pathogenic Cryptococcus species, and related species from the sister genus Kwoniella. Chromosome-level genome assemblies were generated for multiple species of both genera, resulting in a dataset encompassing virtually all of their known diversity. Although Cryptococcus and Kwoniella have comparable genome sizes (about 19.2 and 22.9 Mb) and similar gene content, hinting at pre-adaptive pathogenic potential, our analysis found evidence in pathogenic Cryptococcus species of specific examples of gene gain (via horizontal gene transfer) and gene loss, which might represent evolutionary signatures of pathogenic development. Genome analysis also revealed a significant variation in chromosome number and structure between the two genera. By combining synteny analysis and experimental centromere validation, we found that most Cryptococcus species have 14 chromosomes, whereas most Kwoniella species have fewer (11, 8, 5 or even as few as 3). Reduced chromosome number in Kwoniella is associated with formation of giant chromosomes (up to 18 Mb) through repeated chromosome fusion events, each marked by a pericentric inversion and centromere loss. While similar chromosome inversion-fusion patterns were observed in all Kwoniella species with fewer than 14 chromosomes, no such pattern was detected in Cryptococcus. Instead, Cryptococcus species with less than 14 chromosomes, underwent chromosome reductions primarily through rearrangements associated with the loss of repeat-rich centromeres. Additionally, Cryptococcus genomes exhibited frequent interchromosomal translocations, including intercentromeric recombination facilitated by transposons shared between centromeres. Taken together, our findings advance our understanding of genomic changes possibly associated with pathogenicity in Cryptococcus and provide a foundation to elucidate mechanisms of centromere loss and chromosome fusion driving distinct karyotypes in closely related fungal species, including prominent global human pathogens.
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Affiliation(s)
- Marco A. Coelho
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Márcia David-Palma
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Terrance Shea
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Katharine Bowers
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | | | | | - Andreas Gnirke
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Andrey M. Yurkov
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Minou Nowrousian
- Lehrstuhl für Molekulare und Zelluläre Botanik, Ruhr-Universität Bochum, Bochum, Germany
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | | | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
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5
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Poszewiecka B, Gogolewski K, Karolak JA, Stankiewicz P, Gambin A. PhaseDancer: a novel targeted assembler of segmental duplications unravels the complexity of the human chromosome 2 fusion going from 48 to 46 chromosomes in hominin evolution. Genome Biol 2023; 24:205. [PMID: 37697406 PMCID: PMC10496407 DOI: 10.1186/s13059-023-03022-8] [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: 12/16/2022] [Accepted: 07/25/2023] [Indexed: 09/13/2023] Open
Abstract
Resolving complex genomic regions rich in segmental duplications (SDs) is challenging due to the high error rate of long-read sequencing. Here, we describe a targeted approach with a novel genome assembler PhaseDancer that extends SD-rich regions of interest iteratively. We validate its robustness and efficiency using a golden-standard set of human BAC clones and in silico-generated SDs with predefined evolutionary scenarios. PhaseDancer enables extension of the incomplete complex SD-rich subtelomeric regions of Great Ape chromosomes orthologous to the human chromosome 2 (HSA2) fusion site, informing a model of HSA2 formation and unravelling the evolution of human and Great Ape genomes.
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Affiliation(s)
- Barbara Poszewiecka
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Krzysztof Gogolewski
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Justyna A. Karolak
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, 77030 Houston, TX USA
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, 77030 Houston, TX USA
| | - Anna Gambin
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
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6
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Poszewiecka B, Gogolewski K, Stankiewicz P, Gambin A. Revised time estimation of the ancestral human chromosome 2 fusion. BMC Genomics 2022; 23:616. [PMID: 36008753 PMCID: PMC9413910 DOI: 10.1186/s12864-022-08828-7] [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: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/24/2022] Open
Abstract
Background The reduction of the chromosome number from 48 in the Great Apes to 46 in modern humans is thought to result from the end-to-end fusion of two ancestral non-human primate chromosomes forming the human chromosome 2 (HSA2). Genomic signatures of this event are the presence of inverted telomeric repeats at the HSA2 fusion site and a block of degenerate satellite sequences that mark the remnants of the ancestral centromere. It has been estimated that this fusion arose up to 4.5 million years ago (Mya). Results We have developed an enhanced algorithm for the detection and efficient counting of the locally over-represented weak-to-strong (AT to GC) substitutions. By analyzing the enrichment of these substitutions around the fusion site of HSA2 we estimated its formation time at 0.9 Mya with a 95% confidence interval of 0.4-1.5 Mya. Additionally, based on the statistics derived from our algorithm, we have reconstructed the evolutionary distances among the Great Apes (Hominoidea). Conclusions Our results shed light on the HSA2 fusion formation and provide a novel computational alternative for the estimation of the speciation chronology.
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Affiliation(s)
| | | | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, US
| | - Anna Gambin
- Institute of Informatics, Warsaw University, Warsaw, Poland
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7
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Gamba R, Mazzucco G, Wilhelm T, Velikovsky L, Salinas-Luypaert C, Chardon F, Picotto J, Bohec M, Baulande S, Doksani Y, Fachinetti D. Enrichment of centromeric DNA from human cells. PLoS Genet 2022; 18:e1010306. [PMID: 35853083 PMCID: PMC9295943 DOI: 10.1371/journal.pgen.1010306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 06/23/2022] [Indexed: 11/19/2022] Open
Abstract
Centromeres are key elements for chromosome segregation. Canonical centromeres are built over long-stretches of tandem repetitive arrays. Despite being quite abundant compared to other loci, centromere sequences overall still represent only 2 to 5% of the human genome, therefore studying their genetic and epigenetic features is a major challenge. Furthermore, sequencing of centromeric regions requires high coverage to fully analyze length and sequence variations, and this can be extremely costly. To bypass these issues, we have developed a technique, named CenRICH, to enrich for centromeric DNA from human cells based on selective restriction digestion and size fractionation. Combining restriction enzymes cutting at high frequency throughout the genome, except within most human centromeres, with size-selection of fragments >20 kb, resulted in over 25-fold enrichment in centromeric DNA. High-throughput sequencing revealed that up to 60% of the DNA in the enriched samples is made of centromeric repeats. We show that this method can be used in combination with long-read sequencing to investigate the DNA methylation status of certain centromeres and, with a specific enzyme combination, also of their surrounding regions (mainly HSATII). Finally, we show that CenRICH facilitates single-molecule analysis of replicating centromeric fibers by DNA combing. This approach has great potential for making sequencing of centromeric DNA more affordable and efficient and for single DNA molecule studies.
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Affiliation(s)
- Riccardo Gamba
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France
| | - Giulia Mazzucco
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Therese Wilhelm
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France
| | - Leonid Velikovsky
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France
| | | | - Florian Chardon
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France
| | - Julien Picotto
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris, France
| | - Mylène Bohec
- Institut Curie, Genomics of Excellence (ICGex) Platform, PSL Research University, Paris, France
| | - Sylvain Baulande
- Institut Curie, Genomics of Excellence (ICGex) Platform, PSL Research University, Paris, France
| | - Ylli Doksani
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
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8
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Feliciello I, Pezer Ž, Kordiš D, Bruvo Mađarić B, Ugarković Đ. Evolutionary History of Alpha Satellite DNA Repeats Dispersed within Human Genome Euchromatin. Genome Biol Evol 2021; 12:2125-2138. [PMID: 33078196 PMCID: PMC7719264 DOI: 10.1093/gbe/evaa224] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2020] [Indexed: 01/03/2023] Open
Abstract
Major human alpha satellite DNA repeats are preferentially assembled within (peri)centromeric regions but are also dispersed within euchromatin in the form of clustered or short single repeat arrays. To study the evolutionary history of single euchromatic human alpha satellite repeats (ARs), we analyzed their orthologous loci across the primate genomes. The continuous insertion of euchromatic ARs throughout the evolutionary history of primates starting with the ancestors of Simiformes (45-60 Ma) and continuing up to the ancestors of Homo is revealed. Once inserted, the euchromatic ARs were stably transmitted to the descendant species, some exhibiting copy number variation, whereas their sequence divergence followed the species phylogeny. Many euchromatic ARs have sequence characteristics of (peri)centromeric alpha repeats suggesting heterochromatin as a source of dispersed euchromatic ARs. The majority of euchromatic ARs are inserted in the vicinity of other repetitive elements such as L1, Alu, and ERV or are embedded within them. Irrespective of the insertion context, each AR insertion seems to be unique and once inserted, ARs do not seem to be subsequently spread to new genomic locations. In spite of association with (retro)transposable elements, there is no indication that such elements play a role in ARs proliferation. The presence of short duplications at most of ARs insertion sites suggests site-directed recombination between homologous motifs in ARs and in the target genomic sequence, probably mediated by extrachromosomal circular DNA, as a mechanism of spreading within euchromatin.
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Affiliation(s)
- Isidoro Feliciello
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia.,Dipartimento di Medicina Clinica e Chirurgia, Universita' degli Studi di Napoli Federico II, Italy
| | - Željka Pezer
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Dušan Kordiš
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia
| | | | - Đurđica Ugarković
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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9
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Sun C, Li J, Dong J, Niu Y, Hu J, Lian J, Li W, Li J, Tian Y, Shi Q, Ye X. Chromosome-level genome assembly for the largemouth bass Micropterus salmoides provides insights into adaptation to fresh and brackish water. Mol Ecol Resour 2020; 21:301-315. [PMID: 32985096 DOI: 10.1111/1755-0998.13256] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 12/16/2022]
Abstract
Largemouth bass (LMB; Micropterus salmoides) has been an economically important fish in North America, Europe, and China. This study obtained a chromosome-level genome assembly of LMB using PacBio and Hi-C sequencing. The final assembled genome is 964 Mb, with contig N50 and scaffold N50 values of 1.23 Mb and 36.48 Mb, respectively. Combining with RNA sequencing data, we annotated a total of 23,701 genes. Chromosomal assembly and syntenic analysis proved that, unlike most Perciformes with the popular haploid chromosome number of 24, LMB has only 23 chromosomes (Chr), among which the Chr1 seems to be resulted from a chromosomal fusion event. LMB is phylogenetically closely related to European seabass and spotted seabass, diverging 64.1 million years ago (mya) from the two seabass species. Eight gene families comprising 294 genes associated with ionic regulation were identified through positive selection, transcriptome and genome comparisons. These genes involved in iron facilitated diffusion (such as claudin, aquaporins, sodium channel protein and so on) and others related to ion active transport (such as sodium/potassium-transporting ATPase and sodium/calcium exchanger). The claudin gene family, which is critical for regulating cell tight junctions and osmotic homeostasis, showed a significant expansion in LMB with 27 family members and 68 copies for salinity adaptation. In summary, we reported the first high-quality LMB genome, and provided insights into the molecular mechanisms of LMB adaptation to fresh and brackish water. The chromosome-level LMB genome will also be a valuable genomic resource for in-depth biological and evolutionary studies, germplasm conservation and genetic breeding of LMB.
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Affiliation(s)
- Chengfei Sun
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Jia Li
- Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen, China
| | - Junjian Dong
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | | | - Jie Hu
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | | | - Wuhui Li
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Jiang Li
- Biozeron Shenzhen Inc., Shenzhen, China
| | - Yuanyuan Tian
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Qiong Shi
- Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen, China
| | - Xing Ye
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
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10
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Ruckman SN, Jonika MM, Casola C, Blackmon H. Chromosome number evolves at equal rates in holocentric and monocentric clades. PLoS Genet 2020; 16:e1009076. [PMID: 33048946 PMCID: PMC7584213 DOI: 10.1371/journal.pgen.1009076] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/23/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Despite the fundamental role of centromeres two different types are observed across plants and animals. Monocentric chromosomes possess a single region that function as the centromere while in holocentric chromosomes centromere activity is spread across the entire chromosome. Proper segregation may fail in species with monocentric chromosomes after a fusion or fission, which may lead to chromosomes with no centromere or multiple centromeres. In contrast, species with holocentric chromosomes should still be able to safely segregate chromosomes after fusion or fission. This along with the observation of high chromosome number in some holocentric clades has led to the hypothesis that holocentricity leads to higher rates of chromosome number evolution. To test for differences in rates of chromosome number evolution between these systems, we analyzed data from 4,393 species of insects in a phylogenetic framework. We found that insect orders exhibit striking differences in rates of fissions, fusions, and polyploidy. However, across all insects we found no evidence that holocentric clades have higher rates of fissions, fusions, or polyploidy than monocentric clades. Our results suggest that holocentricity alone does not lead to higher rates of chromosome number changes. Instead, we suggest that other co-evolving traits must explain striking differences between clades.
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Affiliation(s)
- Sarah N. Ruckman
- Department of Biology, Texas A&M University, Texas, United States of America
- Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, Texas, United States of America
| | - Michelle M. Jonika
- Department of Biology, Texas A&M University, Texas, United States of America
- Genetics Interdisciplinary Program, Texas A&M University, Texas, United States of America
| | - Claudio Casola
- Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, Texas, United States of America
- Genetics Interdisciplinary Program, Texas A&M University, Texas, United States of America
- Department of Ecology and Conservation Biology, Texas A&M, Texas, United States of America
| | - Heath Blackmon
- Department of Biology, Texas A&M University, Texas, United States of America
- Ecology and Evolutionary Biology Interdisciplinary Program, Texas A&M University, Texas, United States of America
- Genetics Interdisciplinary Program, Texas A&M University, Texas, United States of America
- * E-mail:
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11
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Sylvester T, Hjelmen CE, Hanrahan SJ, Lenhart PA, Johnston JS, Blackmon H. Lineage-specific patterns of chromosome evolution are the rule not the exception in Polyneoptera insects. Proc Biol Sci 2020; 287:20201388. [PMID: 32993470 PMCID: PMC7542826 DOI: 10.1098/rspb.2020.1388] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/03/2020] [Indexed: 11/13/2022] Open
Abstract
The structure of a genome can be described at its simplest by the number of chromosomes and the sex chromosome system it contains. Despite over a century of study, the evolution of genome structure on this scale remains recalcitrant to broad generalizations that can be applied across clades. To address this issue, we have assembled a dataset of 823 karyotypes from the insect group Polyneoptera. This group contains orders with a range of variations in chromosome number, and offer the opportunity to explore the possible causes of these differences. We have analysed these data using both phylogenetic and taxonomic approaches. Our analysis allows us to assess the importance of rates of evolution, phylogenetic history, sex chromosome systems, parthenogenesis and genome size on variation in chromosome number within clades. We find that fusions play a key role in the origin of new sex chromosomes, and that orders exhibit striking differences in rates of fusions, fissions and polyploidy. Our results suggest that the difficulty in finding consistent rules that govern evolution at this scale may be due to the presence of many interacting forces that can lead to variation among groups.
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Affiliation(s)
- Terrence Sylvester
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Carl E. Hjelmen
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Shawn J. Hanrahan
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Paul A. Lenhart
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - J. Spencer Johnston
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
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12
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Schotanus K, Heitman J. Centromere deletion in Cryptococcus deuterogattii leads to neocentromere formation and chromosome fusions. eLife 2020; 9:56026. [PMID: 32310085 PMCID: PMC7188483 DOI: 10.7554/elife.56026] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/16/2020] [Indexed: 02/06/2023] Open
Abstract
The human fungal pathogen Cryptococcus deuterogattii is RNAi-deficient and lacks active transposons in its genome. C. deuterogattii has regional centromeres that contain only transposon relics. To investigate the impact of centromere loss on the C. deuterogattii genome, either centromere 9 or 10 was deleted. Deletion of either centromere resulted in neocentromere formation and interestingly, the genes covered by these neocentromeres maintained wild-type expression levels. In contrast to cen9∆ mutants, cen10∆ mutant strains exhibited growth defects and were aneuploid for chromosome 10. At an elevated growth temperature (37°C), the cen10∆ chromosome was found to have undergone fusion with another native chromosome in some isolates and this fusion restored wild-type growth. Following chromosomal fusion, the neocentromere was inactivated, and the native centromere of the fused chromosome served as the active centromere. The neocentromere formation and chromosomal fusion events observed in this study in C. deuterogattii may be similar to events that triggered genomic changes within the Cryptococcus/Kwoniella species complex and may contribute to speciation throughout the eukaryotic domain.
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Affiliation(s)
- Klaas Schotanus
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
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13
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Sullivan LL, Sullivan BA. Genomic and functional variation of human centromeres. Exp Cell Res 2020; 389:111896. [PMID: 32035947 PMCID: PMC7140587 DOI: 10.1016/j.yexcr.2020.111896] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/29/2020] [Accepted: 02/05/2020] [Indexed: 10/25/2022]
Abstract
Centromeres are central to chromosome segregation and genome stability, and thus their molecular foundations are important for understanding their function and the ways in which they go awry. Human centromeres typically form at large megabase-sized arrays of alpha satellite DNA for which there is little genomic understanding due to its repetitive nature. Consequently, it has been difficult to achieve genome assemblies at centromeres using traditional next generation sequencing approaches, so that centromeres represent gaps in the current human genome assembly. The role of alpha satellite DNA has been debated since centromeres can form, albeit rarely, on non-alpha satellite DNA. Conversely, the simple presence of alpha satellite DNA is not sufficient for centromere function since chromosomes with multiple alpha satellite arrays only exhibit a single location of centromere assembly. Here, we discuss the organization of human centromeres as well as genomic and functional variation in human centromere location, and current understanding of the genomic and epigenetic mechanisms that underlie centromere flexibility in humans.
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Affiliation(s)
| | - Beth A Sullivan
- Department of Molecular Genetics and Microbiology, USA; Division of Human Genetics, Duke University School of Medicine, Durham, NC, 27710, USA.
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14
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Chiatante G, Giannuzzi G, Calabrese FM, Eichler EE, Ventura M. Centromere Destiny in Dicentric Chromosomes: New Insights from the Evolution of Human Chromosome 2 Ancestral Centromeric Region. Mol Biol Evol 2017; 34:1669-1681. [PMID: 28333343 DOI: 10.1093/molbev/msx108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Dicentric chromosomes are products of genomic rearrangements that place two centromeres on the same chromosome. Due to the presence of two primary constrictions, they are inherently unstable and overcome their instability by epigenetically inactivating and/or deleting one of the two centromeres, thus resulting in functionally monocentric chromosomes that segregate normally during cell division. Our understanding to date of dicentric chromosome formation, behavior and fate has been largely inferred from observational studies in plants and humans as well as artificially produced de novo dicentrics in yeast and in human cells. We investigate the most recent product of a chromosome fusion event fixed in the human lineage, human chromosome 2, whose stability was acquired by the suppression of one centromere, resulting in a unique difference in chromosome number between humans (46 chromosomes) and our most closely related ape relatives (48 chromosomes). Using molecular cytogenetics, sequencing, and comparative sequence data, we deeply characterize the relicts of the chromosome 2q ancestral centromere and its flanking regions, gaining insight into the ancestral organization that can be easily broadened to all acrocentric chromosome centromeres. Moreover, our analyses offered the opportunity to trace the evolutionary history of rDNA and satellite III sequences among great apes, thus suggesting a new hypothesis for the preferential inactivation of some human centromeres, including IIq. Our results suggest two possible centromere inactivation models to explain the evolutionarily stabilization of human chromosome 2 over the last 5-6 million years. Our results strongly favor centromere excision through a one-step process.
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Affiliation(s)
- Giorgia Chiatante
- Department of Biology, University of Bari "Aldo Moro", Bari, Italy.,Department of Biology, Anthropology Laboratories University of Florence, Florence, Italy
| | - Giuliana Giannuzzi
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | | | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA.,Howard Hughes Medical Institute, University of Washington, Seattle, WA
| | - Mario Ventura
- Department of Biology, University of Bari "Aldo Moro", Bari, Italy
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15
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Stankiewicz P. One pedigree we all may have come from - did Adam and Eve have the chromosome 2 fusion? Mol Cytogenet 2016; 9:72. [PMID: 27708712 PMCID: PMC5037601 DOI: 10.1186/s13039-016-0283-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/16/2016] [Indexed: 11/18/2022] Open
Abstract
Background In contrast to Great Apes, who have 48 chromosomes, modern humans and likely Neandertals and Denisovans have and had, respectively, 46 chromosomes. The reduction in chromosome number was caused by the head-to-head fusion of two ancestral chromosomes to form human chromosome 2 (HSA2) and may have contributed to the reproductive barrier with Great Apes. Results Next generation sequencing and molecular clock analyses estimated that this fusion arose prior to our last common ancestor with Neandertal and Denisovan hominins ~ 0.74 - 4.5 million years ago. Hypotheses I propose that, unlike recurrent Robertsonian translocations in humans, the HSA2 fusion was a single nonrecurrent event that spread through a small polygamous clan population bottleneck. Its heterozygous to homozygous conversion, fixation, and accumulation in the succeeding populations was likely facilitated by an evolutionary advantage through the genomic loss rather than deregulation of expression of the gene(s) flanking the HSA2 fusion site at 2q13. Conclusions The origin of HSA2 might have been a critical evolutionary event influencing higher cognitive functions in various early subspecies of hominins. Next generation sequencing of Homo heidelbergensis and Homo erectus genomes and complete reconstruction of DNA sequence of the orthologous subtelomeric chromosomes in Great Apes should enable more precise timing of HSA2 formation and better understanding of its evolutionary consequences.
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Affiliation(s)
- Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Rm ABBR-R809, Houston, TX 77030 USA
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