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Thote V, Dinesh S, Sharma S. Prediction of deleterious non-synonymous SNPs of human MDC1 gene: an in silico approach. Syst Biol Reprod Med 2024; 70:101-112. [PMID: 38630598 DOI: 10.1080/19396368.2024.2325699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/24/2024] [Indexed: 04/19/2024]
Abstract
MDC1 (Mediator of DNA damage Checkpoint protein 1) functions to facilitate the localization of numerous DNA damage response (DDR) components to DNA double-strand break sites. MDC1 is an integral component in preserving genomic stability and appropriate DDR regulation. There haven't been systematic investigations of MDC1 mutations that induce cancer and genomic instability. Variations in nsSNPs have the potential to modify the protein chemistry and their function. Describing functional SNPs in disease-associated genes presents a significant conundrum for investigators, it is possible to assess potential functional SNPs before conducting larger population examinations. Multiple sequences and structure-based bioinformatics strategies were implemented in the current in-silico investigation to discern potential nsSNPs of the MDC1 genes. The nsSNPs were identified with SIFT, SNAP2, Align GVGD, PolyPhen-2, and PANTHER, and their stability was determined with MUpro. The conservation, solvent accessibility, and structural effects of the mutations were identified with ConSurf, NetSurfP-2.0, and SAAFEC-SEQ respectively. Cancer-related analysis of the nsSNPs was conducted using cBioPortal and TCGA web servers. The present study appraised five nsSNPs (P1426T, P69S, P194R, P203L, and H131Y) as probably mutilating due to their existence in highly conserved regions and propensity to deplete protein stability. The nsSNPs P194R, P203L, and H131Y were concluded as deleterious and possibly damaging from the 5 prediction tools. The functional nsSNP P194R mutation is associated with skin cutaneous melanoma while no significant records were found for other nsSNPs. The present study concludes that the highly deleterious P194R mutations can potentially induce genomic instability and contribute to various cancers' pathogenesis. Developing drugs targeting these mutations can undoubtedly be advantageous in large population-based studies, particularly in the development of precision medicine.
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Affiliation(s)
| | - Susha Dinesh
- Department of Bioinformatics, BioNome, Bengaluru, India
| | - Sameer Sharma
- Department of Bioinformatics, BioNome, Bengaluru, India
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2
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Xu K. Effects of selfing on the evolution of sexual reproduction. Evolution 2024; 78:879-893. [PMID: 38280201 DOI: 10.1093/evolut/qpae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 01/11/2024] [Accepted: 01/24/2024] [Indexed: 01/29/2024]
Abstract
Plants exhibit diverse breeding systems, with populations capable of outcrossing, selfing, and/or asexual reproduction. However, interactions between the three reproductive pathways remain not fully clear. Sexual reproduction introduces segregation and recombination, but incurs several costs. Selfing can affect the relative costs and benefits of sexual vs. asexual reproduction. Building population genetic models, I explore how selfing affects the evolution of a sexual reproduction rate modifier via (a) indirect selection due to segregation, (b) indirect selection from changes in recombination rates, and (c) selection from the cost of meiosis and mate limitation. The dominant selective force mediating the evolution of sex is found to vary with the rate of sexual reproduction and selfing, but selective force (a) and (c) are generally stronger than selective force (b). A modifier enhancing sexual reproduction tends to be favored by indirect selection generated by partially recessive, small-effect deleterious mutations, while hindered by highly recessive lethal mutations. Overall, evolution toward higher sexual reproduction is hindered at low sexual reproduction rates and intermediate selfing rates, but favored under high selfing rates. The results suggest that asexual reproduction may precede the evolution of selfing and offer insights into the evolution of mechanisms reducing geitonogamy in partially clonal populations.
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Affiliation(s)
- Kuangyi Xu
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, Canada
- Department of Biology, University of North Carolina, Chapel Hill, NC, United States
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3
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Shafie A, Ashour AA, Anjum F, Shamsi A, Hassan MI. Elucidating the Impact of Deleterious Mutations on IGHG1 and Their Association with Huntington's Disease. J Pers Med 2024; 14:380. [PMID: 38673007 PMCID: PMC11050829 DOI: 10.3390/jpm14040380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
Huntington's disease (HD) is a chronic, inherited neurodegenerative condition marked by chorea, dementia, and changes in personality. The primary cause of HD is a mutation characterized by the expansion of a triplet repeat (CAG) within the huntingtin gene located on chromosome 4. Despite substantial progress in elucidating the molecular and cellular mechanisms of HD, an effective treatment for this disorder is not available so far. In recent years, researchers have been interested in studying cerebrospinal fluid (CSF) as a source of biomarkers that could aid in the diagnosis and therapeutic development of this disorder. Immunoglobulin heavy constant gamma 1 (IGHG1) is one of the CSF proteins found to increase significantly in HD. Considering this, it is reasonable to study the potential involvement of deleterious mutations in IGHG1 in the pathogenesis of this disorder. In this study, we explored the potential impact of deleterious mutations on IGHG1 and their subsequent association with HD. We evaluated 126 single-point amino acid substitutions for their impact on the structure and functionality of the IGHG1 protein while exploiting multiple computational resources such as SIFT, PolyPhen-2, FATHMM, SNPs&Go mCSM, DynaMut2, MAESTROweb, PremPS, MutPred2, and PhD-SNP. The sequence- and structure-based tools highlighted 10 amino acid substitutions that were deleterious and destabilizing. Subsequently, out of these 10 mutations, eight variants (Y32C, Y32D, P34S, V39E, C83R, C83Y, V85M, and H87Q) were identified as pathogenic by disease phenotype predictors. Finally, two pathogenic variants (Y32C and P34S) were found to reduce the solubility of the protein, suggesting their propensity to form protein aggregates. These variants also exhibited higher residual frustration within the protein structure. Considering these findings, the study hypothesized that the identified variants of IGHG1 may compromise its function and potentially contribute to HD pathogenesis.
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Affiliation(s)
- Alaa Shafie
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; (A.S.); (F.A.)
| | - Amal Adnan Ashour
- Department of Oral and Maxillofacial Surgery and Diagnostic Sciences, Faculty of Dentistry, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia;
| | - Farah Anjum
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; (A.S.); (F.A.)
| | - Anas Shamsi
- Center of Medical and Bio-Allied Health Sciences Research (CMBHSR), Ajman University, Ajman P.O. Box 346, United Arab Emirates
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
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Cui R, Wu J, Yan K, Luo S, Hu Y, Feng W, Lu B, Wang J. Phased genome assemblies reveal haplotype-specific genetic load in the critically endangered Chinese Bahaba (Teleostei, Sciaenidae). Mol Ecol 2024; 33:e17250. [PMID: 38179694 DOI: 10.1111/mec.17250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 01/06/2024]
Abstract
While haplotype-specific genetic load shapes the evolutionary trajectory of natural and captive populations, mixed-haplotype assembly and genotyping hindered its characterization in diploids. Herein, we produced two phased genome assemblies of the critically endangered fish Chinese Bahaba (Bahaba taipingensis, Sciaenidae, Teleostei) and resequenced 20 whole genomes to quantify population genetic load at a haplotype level. We identified frame-shifting variants as the most deleterious type, followed by mutations in the 5'-UTR, 3'-UTR and missense mutations at conserved amino acids. Phased haplotypes revealed gene deletions and high-impact deleterious variants. We estimated ~1.12% of genes missing or interrupted per haplotype, with a significant overlap of disrupted genes (30.35%) between haplotype sets. Relative proportions of deleterious variant categories differed significantly between haplotypes. Simulations suggested that purifying selection struggled to purge slightly deleterious genetic load in captive breeding compared to genotyping interventions, and that higher inter-haplotypic variance of genetic load predicted more efficient purging by artificial selection. Combining the knowledge of haplotype-resolved genetic load with predictive modelling will be immensely useful for understanding the evolution of deleterious variants and guiding conservation planning.
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Affiliation(s)
- Rongfeng Cui
- School of Ecology & State Key Laboratory of Biocontrol, Sun Yat-sen University, Shenzhen, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Jinxian Wu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong-Macao Joint Laboratory for Aquaculture Breeding Development and Innovation, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Kuoqiu Yan
- Huangjing Marine Biotechnology Co. Ltd., Huizhou, China
| | - Sujun Luo
- Dongguan Forestry Affairs Center, Dongguan, China
| | - Yuting Hu
- Dongguan Forestry Affairs Center, Dongguan, China
| | - Wei Feng
- Dongguan Forestry Affairs Center, Dongguan, China
| | - Bingqian Lu
- Dongguan Forestry Affairs Center, Dongguan, China
| | - Junjie Wang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong-Macao Joint Laboratory for Aquaculture Breeding Development and Innovation, School of Life Sciences, South China Normal University, Guangzhou, China
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Hastings IM. The impact of Fisher's reproductive compensation on raising equilibrium frequencies of semidominant, nonlethal mutations under mutation/selection balance. G3 (Bethesda) 2023; 14:jkad231. [PMID: 37972212 PMCID: PMC10755198 DOI: 10.1093/g3journal/jkad231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 08/28/2023] [Indexed: 11/19/2023]
Abstract
Fisher's reproductive compensation (fRC) occurs when a species' demography means the death of an individual results in increased survival probability of his/her relatives, usually assumed to be full sibs. This likely occurs in many species, including humans. Several important recessive human genetic diseases cause early foetal/infant death allowing fRC to act on these mutations. The impact of fRC on these genetic conditions has been previously calculated and shown to be substantial as quantified by ω, the fold increase in equilibrium frequencies of the mutation under fRC compared with its absence, i.e. ω = 1.22 and ω = 1.33 for autosomal and sex-linked loci, respectively. However, the impact of fRC on the frequency of the much larger class of semidominant, nonlethal mutations is unknown. This is calculated here as ω = 2 - h*s for autosomal loci and ω up to 2 for sex-linked loci where h is dominance (varied between 0.05 and 0.95) and s is selection coefficient (varied between 0.05 and 0.9). These results show that the actions of fRC can almost double the equilibrium frequency of deleterious mutations with low values of h and/or s (noting that "low" is s∼0.05 to 0.1). It is noted that fRC may act differentially across the genome with genes expressed early in life being fully exposed to fRC while those expressed later in life may be unaffected; this could lead to systematic differences in deleterious allele frequency across the genome.
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Affiliation(s)
- Ian M Hastings
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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6
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Kyriazis CC, Robinson JA, Lohmueller KE. Using Computational Simulations to Model Deleterious Variation and Genetic Load in Natural Populations. Am Nat 2023; 202:737-752. [PMID: 38033186 PMCID: PMC10897732 DOI: 10.1086/726736] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
AbstractDeleterious genetic variation is abundant in wild populations, and understanding the ecological and conservation implications of such variation is an area of active research. Genomic methods are increasingly used to quantify the impacts of deleterious variation in natural populations; however, these approaches remain limited by an inability to accurately predict the selective and dominance effects of mutations. Computational simulations of deleterious variation offer a complementary tool that can help overcome these limitations, although such approaches have yet to be widely employed. In this perspective article, we aim to encourage ecological and conservation genomics researchers to adopt greater use of computational simulations to aid in deepening our understanding of deleterious variation in natural populations. We first provide an overview of the components of a simulation of deleterious variation, describing the key parameters involved in such models. Next, we discuss several approaches for validating simulation models. Finally, we compare and validate several recently proposed deleterious mutation models, demonstrating that models based on estimates of selection parameters from experimental systems are biased toward highly deleterious mutations. We describe a new model that is supported by multiple orthogonal lines of evidence and provide example scripts for implementing this model (https://github.com/ckyriazis/simulations_review).
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7
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James J, Kastally C, Budde KB, González-Martínez SC, Milesi P, Pyhäjärvi T, Lascoux M. Between but Not Within-Species Variation in the Distribution of Fitness Effects. Mol Biol Evol 2023; 40:msad228. [PMID: 37832225 PMCID: PMC10630145 DOI: 10.1093/molbev/msad228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 09/04/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is, therefore, of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, that is whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterized the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence, and genetic background. We find statistical support for the presence of variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and those evolutionarily recent events, such as demographic changes and local adaptation, have little impact.
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Affiliation(s)
- Jennifer James
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
- Swedish Collegium of Advanced Study, Uppsala University, Uppsala, Sweden
| | - Chedly Kastally
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Katharina B Budde
- Department of Forest Genetics and Forest Tree Breeding, Georg-August-University Goettingen, Goettingen, Germany
- Center of Biodiversity and Sustainable Land Use (CBL), University of Goettingen, Goettingen, Germany
| | - Santiago C González-Martínez
- National Research Institute for Agriculture, Food and the Environment (INRAE), University of Bordeaux, BIOGECO, Cestas, France
| | - Pascal Milesi
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
- Science for Life Laboratory (SciLifeLab), Uppsala University, Uppsala, Sweden
| | - Tanja Pyhäjärvi
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Martin Lascoux
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
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Le Veve A, Burghgraeve N, Genete M, Lepers-Blassiau C, Takou M, De Meaux J, Mable BK, Durand E, Vekemans X, Castric V. Long-term balancing selection and the genetic load linked to the self-incompatibility locus in Arabidopsis halleri and A. lyrata. Mol Biol Evol 2023:7175058. [PMID: 37210585 DOI: 10.1093/molbev/msad120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/09/2023] [Accepted: 05/16/2023] [Indexed: 05/22/2023] Open
Abstract
Balancing selection is a form of natural selection maintaining diversity at the sites it targets and at linked nucleotide sites. Due to selection favouring heterozygosity, it has the potential to facilitate the accumulation of a "sheltered" load of tightly linked recessive deleterious mutations. However, precisely evaluating the extent of these effects has remained challenging. Taking advantage of plant self-incompatibility as one of the best-understood examples of long-term balancing selection, we provide a highly resolved picture of the genomic extent of balancing selection on the sheltered genetic load. We used targeted genome resequencing to reveal polymorphism of the genomic region flanking the self-incompatibility locus in three sample sets in each of the two closely related plant species Arabidopsis halleri and A. lyrata, and used 100 control regions from throughout the genome to factor out differences in demographic histories and/or sample structure. Nucleotide polymorphism increased strongly around the S-locus in all sample sets, but only over a limited genomic region, as it became indistinguishable from the genomic background beyond the first 25-30 kb. Genes in this chromosomal interval exhibited no excess of mutations at 0-fold degenerated sites relative to putatively neutral sites, hence revealing no detectable weakening of the efficacy of purifying selection even for these most tightly linked genes. Overall, our results are consistent with the predictions of a narrow genomic influence of linkage to the S-locus, and clarify how natural selection in one genomic region affects the evolution of the adjacent genomic regions.
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Affiliation(s)
- Audrey Le Veve
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01 Prague, Czechia
| | | | - Mathieu Genete
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | | | - Margarita Takou
- Institute of Botany, University of Cologne, Cologne, Germany
- Department of Biology, Pennsylvania State University, PA, United States of America
| | | | - Barbara K Mable
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Eléonore Durand
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Xavier Vekemans
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Vincent Castric
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
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Humble E, Stoffel MA, Dicks K, Ball AD, Gooley RM, Chuven J, Pusey R, Remeithi MA, Koepfli KP, Pukazhenthi B, Senn H, Ogden R. Conservation management strategy impacts inbreeding and mutation load in scimitar-horned oryx. Proc Natl Acad Sci U S A 2023; 120:e2210756120. [PMID: 37098062 PMCID: PMC10160979 DOI: 10.1073/pnas.2210756120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
In an age of habitat loss and overexploitation, small populations, both captive and wild, are increasingly facing the effects of isolation and inbreeding. Genetic management has therefore become a vital tool for ensuring population viability. However, little is known about how the type and intensity of intervention shape the genomic landscape of inbreeding and mutation load. We address this using whole-genome sequence data of the scimitar-horned oryx (Oryx dammah), an iconic antelope that has been subject to contrasting management strategies since it was declared extinct in the wild. We show that unmanaged populations are enriched for long runs of homozygosity (ROH) and have significantly higher inbreeding coefficients than managed populations. Additionally, despite the total number of deleterious alleles being similar across management strategies, the burden of homozygous deleterious genotypes was consistently higher in unmanaged groups. These findings emphasize the risks associated with deleterious mutations through multiple generations of inbreeding. As wildlife management strategies continue to diversify, our study reinforces the importance of maintaining genome-wide variation in vulnerable populations and has direct implications for one of the largest reintroduction attempts in the world.
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Affiliation(s)
- Emily Humble
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, United Kingdom
| | - Martin A Stoffel
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Kara Dicks
- RZSS WildGenes, Conservation Department, Royal Zoological Society of Scotland, Edinburgh EH12 6TS, United Kingdom
| | - Alex D Ball
- RZSS WildGenes, Conservation Department, Royal Zoological Society of Scotland, Edinburgh EH12 6TS, United Kingdom
| | - Rebecca M Gooley
- Smithsonian-Mason School of Conservation, George Mason University, Front Royal, VA 22630
- Smithsonian's National Zoo and Conservation Biology Institute, Center for Species Survival, Front Royal, VA 22630 and Washington, DC 20008
| | - Justin Chuven
- Terrestrial & Marine Biodiversity Sector, Environment Agency - Abu Dhabi, United Arab Emirates
- US Fish and Wildlife Service, CO 80612
| | - Ricardo Pusey
- Terrestrial & Marine Biodiversity Sector, Environment Agency - Abu Dhabi, United Arab Emirates
| | - Mohammed Al Remeithi
- Terrestrial & Marine Biodiversity Sector, Environment Agency - Abu Dhabi, United Arab Emirates
| | - Klaus-Peter Koepfli
- Smithsonian-Mason School of Conservation, George Mason University, Front Royal, VA 22630
- Smithsonian's National Zoo and Conservation Biology Institute, Center for Species Survival, Front Royal, VA 22630 and Washington, DC 20008
| | - Budhan Pukazhenthi
- Smithsonian's National Zoo and Conservation Biology Institute, Center for Species Survival, Front Royal, VA 22630 and Washington, DC 20008
| | - Helen Senn
- RZSS WildGenes, Conservation Department, Royal Zoological Society of Scotland, Edinburgh EH12 6TS, United Kingdom
| | - Rob Ogden
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh EH25 9RG, United Kingdom
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10
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Wu Y, Li D, Hu Y, Li H, Ramstein GP, Zhou S, Zhang X, Bao Z, Zhang Y, Song B, Zhou Y, Zhou Y, Gagnon E, Särkinen T, Knapp S, Zhang C, Städler T, Buckler ES, Huang S. Phylogenomic discovery of deleterious mutations facilitates hybrid potato breeding. Cell 2023; 186:2313-2328.e15. [PMID: 37146612 DOI: 10.1016/j.cell.2023.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 02/20/2023] [Accepted: 04/05/2023] [Indexed: 05/07/2023]
Abstract
Hybrid potato breeding will transform the crop from a clonally propagated tetraploid to a seed-reproducing diploid. Historical accumulation of deleterious mutations in potato genomes has hindered the development of elite inbred lines and hybrids. Utilizing a whole-genome phylogeny of 92 Solanaceae and its sister clade species, we employ an evolutionary strategy to identify deleterious mutations. The deep phylogeny reveals the genome-wide landscape of highly constrained sites, comprising ∼2.4% of the genome. Based on a diploid potato diversity panel, we infer 367,499 deleterious variants, of which 50% occur at non-coding and 15% at synonymous sites. Counterintuitively, diploid lines with relatively high homozygous deleterious burden can be better starting material for inbred-line development, despite showing less vigorous growth. Inclusion of inferred deleterious mutations increases genomic-prediction accuracy for yield by 24.7%. Our study generates insights into the genome-wide incidence and properties of deleterious mutations and their far-reaching consequences for breeding.
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Affiliation(s)
- Yaoyao Wu
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; Institute for Genomic Diversity, Cornell University, Ithaca, NY 14853, USA
| | - Dawei Li
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; State Key Laboratory of Tropical Crop Breeding, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China
| | - Yong Hu
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; The AGISCAAS-YNNU Joint Academy of Potato Sciences, Yunnan Normal University, Kunming, Yunnan 650500, China
| | - Hongbo Li
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Guillaume P Ramstein
- Center for Quantitative Genetics and Genomics, Aarhus University, Aarhus 8000, Denmark
| | - Shaoqun Zhou
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Xinyan Zhang
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Zhigui Bao
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; Department of Molecular Biology, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Yu Zhang
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; School of Agriculture, Sun Yat-sen University, Shenzhen, Guangdong 518107, China
| | - Baoxing Song
- Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong 261000, China
| | - Yao Zhou
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100094, China
| | - Yongfeng Zhou
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Edeline Gagnon
- Technische Universität München, TUM School of Life Sciences, Emil-Ramann-Strasse 2, 85354 Freising, Germany
| | - Tiina Särkinen
- Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, UK
| | - Sandra Knapp
- Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Chunzhi Zhang
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Thomas Städler
- Institute of Integrative Biology and Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
| | - Edward S Buckler
- Institute for Genomic Diversity, Cornell University, Ithaca, NY 14853, USA; USDA-ARS, Ithaca, NY 14853, USA
| | - Sanwen Huang
- State Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; State Key Laboratory of Tropical Crop Breeding, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China.
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11
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Mathur S, Tomeček JM, Tarango-Arámbula LA, Perez RM, DeWoody JA. An evolutionary perspective on genetic load in small, isolated populations as informed by whole genome resequencing and forward-time simulations. Evolution 2023; 77:690-704. [PMID: 36626799 DOI: 10.1093/evolut/qpac061] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 01/12/2023]
Abstract
Small populations are vulnerable to increased genetic load and drift that can lead to reductions in fitness and adaptive potential. By analyzing 66 individual whole genomes of Montezuma Quail (Cyrtonyx montezumae) from multiple populations, we illustrate how genetic load is dynamic over evolutionary time. We show that Montezuma Quail are evolving like a ring species, where the terminal extant populations from Arizona and Texas have been separated for ~16,500 years. The Texas populations have remained small but stable since the separation, whereas the Arizona population is much larger today but has been contracting for thousands of years. Most deleterious mutations across the genome are young and segregating privately in each population and a greater number of deleterious alleles are present in the larger population. Our data indicate that ancestral load is purged during strong bottlenecks, but the reduced efficiency of selection in small populations means that segregating deleterious mutations are more likely to rise in frequency over time. Forward-time simulations indicate that severe population declines in historically large populations is more detrimental to individual fitness, whereas long-term small populations are more at risk for reduced adaptive potential and population-level fitness. Our study highlights the intimate connections among evolutionary history, historical demography, genetic load, and evolutionary potential in wild populations.
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Affiliation(s)
- Samarth Mathur
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
| | - John M Tomeček
- Department of Rangeland, Wildlife, and Fisheries Management, Texas A&M University, College Station, TX, United States
| | | | - Robert M Perez
- Texas Parks and Wildlife Department, La Vernia, TX, United States
| | - J Andrew DeWoody
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States.,Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, United States
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12
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Abstract
Deleterious mutations decrease reproductive fitness and are ubiquitous in genomes. Given that many organisms face ongoing threats of extinction, there is interest in elucidating the impact of deleterious variation on extinction risk and optimizing management strategies accounting for such mutations. Quantifying deleterious variation and understanding the effects of population history on deleterious variation are complex endeavors because we do not know the strength of selection acting on each mutation. Further, the effect of demographic history on deleterious mutations depends on the strength of selection against the mutation and the degree of dominance. Here we clarify how deleterious variation can be quantified and studied in natural populations. We then discuss how different demographic factors, such as small population size, nonequilibrium population size changes, inbreeding, and gene flow, affect deleterious variation. Lastly, we provide guidance on studying deleterious variation in nonmodel populations of conservation concern.
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Affiliation(s)
- Jacqueline Robinson
- Institute for Human Genetics, University of California, San Francisco, California, USA;
| | - Christopher C Kyriazis
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; , ,
| | - Stella C Yuan
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; , ,
| | - Kirk E Lohmueller
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA; , , .,Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California, USA
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13
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Abstract
Insects constitute vital components of ecosystems. There is alarming evidence for global declines in insect species diversity, abundance, and biomass caused by anthropogenic drivers such as habitat degradation or loss, agricultural practices, climate change, and environmental pollution. This raises important concerns about human food security and ecosystem functionality and calls for more research to assess insect population trends and identify threatened species and the causes of declines to inform conservation strategies. Analysis of genetic diversity is a powerful tool to address these goals, but so far animal conservation genetics research has focused strongly on endangered vertebrates, devoting less attention to invertebrates, such as insects, that constitute most biodiversity. Insects' shorter generation times and larger population sizes likely necessitate different analytical methods and management strategies. The availability of high-quality reference genome assemblies enables population genomics to address several key issues. These include precise inference of past demographic fluctuations and recent declines, measurement of genetic load levels, delineation of evolutionarily significant units and cryptic species, and analysis of genetic adaptation to stressors. This enables identification of populations that are particularly vulnerable to future threats, considering their potential to adapt and evolve. We review the application of population genomics to insect conservation and the outlook for averting insect declines.
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Affiliation(s)
- Matthew T Webster
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden;
| | - Alexis Beaurepaire
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Eckart Stolle
- Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig, Bonn, Germany
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14
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Smeds L, Ellegren H. From high masked to high realized genetic load in inbred Scandinavian wolves. Mol Ecol 2022; 32:1567-1580. [PMID: 36458895 DOI: 10.1111/mec.16802] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
When new mutations arise at functional sites they are more likely to impair than improve fitness. If not removed by purifying selection, such deleterious mutations will generate a genetic load that can have negative fitness effects in small populations and increase the risk of extinction. This is relevant for the highly inbred Scandinavian wolf (Canis lupus) population, founded by only three wolves in the 1980s and suffering from inbreeding depression. We used functional annotation and evolutionary conservation scores to study deleterious variation in a total of 209 genomes from both the Scandinavian and neighbouring wolf populations in northern Europe. The masked load (deleterious mutations in heterozygote state) was highest in Russia and Finland with deleterious alleles segregating at lower frequency than neutral variation. Genetic drift in the Scandinavian population led to the loss of ancestral alleles, fixation of deleterious variants and a significant increase in the per-individual realized load (deleterious mutations in homozygote state; an increase by 45% in protein-coding genes) over five generations of inbreeding. Arrival of immigrants gave a temporary genetic rescue effect with ancestral alleles re-entering the population and thereby shifting deleterious alleles from homozygous into heterozygote genotypes. However, in the absence of permanent connectivity to Finnish and Russian populations, inbreeding has then again led to the exposure of deleterious mutations. These observations provide genome-wide insight into the magnitude of genetic load and genetic rescue at the molecular level, and in relation to population history. They emphasize the importance of securing gene flow in the management of endangered populations.
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Affiliation(s)
- Linnéa Smeds
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Hans Ellegren
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
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15
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Allman B, Koelle K, Weissman D. Heterogeneity in viral populations increases the rate of deleterious mutation accumulation. Genetics 2022; 222:6673144. [PMID: 35993909 PMCID: PMC9526070 DOI: 10.1093/genetics/iyac127] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
RNA viruses have high mutation rates, with the majority of mutations being deleterious. We examine patterns of deleterious mutation accumulation over multiple rounds of viral replication, with a focus on how cellular coinfection and heterogeneity in viral output affect these patterns. Specifically, using agent-based intercellular simulations we find, in agreement with previous studies, that coinfection of cells by viruses relaxes the strength of purifying selection, and thereby increases the rate of deleterious mutation accumulation. We further find that cellular heterogeneity in viral output exacerbates the rate of deleterious mutation accumulation, regardless of whether this heterogeneity in viral output is stochastic or is due to variation in cellular multiplicity of infection. These results highlight the need to consider the unique life histories of viruses and their population structure to better understand observed patterns of viral evolution.
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Affiliation(s)
- Brent Allman
- Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, Georgia 30322, USA
| | - Katia Koelle
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Daniel Weissman
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA.,Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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16
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van Oosterhout C, Marcu D, Immler S. Accounting for the genetic load in assisted reproductive technology. Clin Transl Med 2022; 12:e864. [PMID: 35613708 PMCID: PMC9132725 DOI: 10.1002/ctm2.864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 04/17/2022] [Accepted: 04/19/2022] [Indexed: 11/10/2022] Open
Abstract
The genetic load in the human genome has important ramifications for assisted reproductive technology (ART), human reproduction and fertility more generally. Here, we discuss these topics in the light of evolutionary genetic theory, the technological revolution in ART and the advances in the fields of genomics and bioinformatics.
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Affiliation(s)
| | - Daniel Marcu
- School of Biological SciencesUniversity of East AngliaNorwichUK
| | - Simone Immler
- School of Biological SciencesUniversity of East AngliaNorwichUK
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17
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Ahamad S, Kanipakam H, Gupta D. Insights into the structural and dynamical changes of spike glycoprotein mutations associated with SARS-CoV-2 host receptor binding. J Biomol Struct Dyn 2022; 40:263-275. [PMID: 32851910 PMCID: PMC7484578 DOI: 10.1080/07391102.2020.1811774] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/13/2020] [Indexed: 12/13/2022]
Abstract
Novel Coronavirus or SARS-CoV-2 has received worldwide attention due to the COVID-19 pandemic, which originated in Wuhan, China leading to thousands of deaths to date. The SARS-CoV-2 Spike glycoprotein protein is one of the main focus of COVID-19 related research as it is a structural protein that facilitates its attachment, entry, and infection to the host cells. We have focused our work on mutations in two of the several functional domains in the virus spike glycoprotein, namely, receptor-binding domain (RBD) and heptad repeat 1 (HR1) domain. These domains are majorly responsible for the stability of spike glycoprotein and play a key role in the host cell attachment and infection. In our study, several mutations like R408I, L455Y, F486L, Q493N, Q498Y, N501T of RBD (319-591), and A930V, D936Y of HR1 (912-984) have been studied to examine its role on the spike glycoprotein native structure. Comparisons of MD simulations in the WT and mutants revealed a significant de-stabilization effect of the mutations on RBD and HR1 domains. We have investigated the impact of mapped mutations on the stability of the spike glycoprotein, before binding to the receptor, which may be consequential to its binding properties to the receptor and other ligands.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Shahzaib Ahamad
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Hema Kanipakam
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Dinesh Gupta
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
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18
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Ackiss AS, Magee MR, Sass GG, Turnquist K, McIntyre PB, Larson WA. Genomic and environmental influences on resilience in a cold-water fish near the edge of its range. Evol Appl 2021; 14:2794-2814. [PMID: 34950230 PMCID: PMC8674893 DOI: 10.1111/eva.13313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 02/06/2023] Open
Abstract
Small, isolated populations present a challenge for conservation. The dueling effects of selection and drift in a limited pool of genetic diversity make the responses of small populations to environmental perturbations erratic and difficult to predict. This is particularly true at the edge of a species range, where populations often persist at the limits of their environmental tolerances. Populations of cisco, Coregonus artedi, in inland lakes have experienced numerous extirpations along the southern edge of their range in recent decades, which are thought to result from environmental degradation and loss of cold, well-oxygenated habitat as lakes warm. Yet, cisco extirpations do not show a clear latitudinal pattern, suggesting that local environmental factors and potentially local adaptation may influence resilience. Here, we used genomic tools to investigate the nature of this pattern of resilience. We used restriction site-associated DNA capture (Rapture) sequencing to survey genomic diversity and differentiation in southern inland lake cisco populations and compared the frequency of deleterious mutations that potentially influence fitness across lakes. We also examined haplotype diversity in a region of the major histocompatibility complex involved in stress and immune system response. We correlated these metrics to spatial and environmental factors including latitude, lake size, and measures of oxythermal habitat and found significant relationships between genetic metrics and broad and local factors. High levels of genetic differentiation among populations were punctuated by a phylogeographic break and residual patterns of isolation-by-distance. Although the prevalence of deleterious mutations and inbreeding coefficients was significantly correlated with latitude, neutral and non-neutral genetic diversity were most strongly correlated with lake surface area. Notably, differences among lakes in the availability of estimated oxythermal habitat left no clear population genomic signature. Our results shed light on the complex dynamics influencing these isolated populations and provide valuable information for their conservation.
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Affiliation(s)
- Amanda S. Ackiss
- Wisconsin Cooperative Fishery Research UnitCollege of Natural ResourcesUniversity of Wisconsin‐Stevens PointStevens PointWisconsinUSA
- U.S. Geological SurveyGreat Lakes Science CenterAnn ArborMichiganUSA
| | | | - Greg G. Sass
- Escanaba Lake Research StationWisconsin Department of Natural ResourcesBoulder JunctionWisconsinUSA
| | - Keith Turnquist
- Wisconsin Cooperative Fishery Research UnitCollege of Natural ResourcesUniversity of Wisconsin‐Stevens PointStevens PointWisconsinUSA
| | - Peter B. McIntyre
- Department of Natural Resources and the EnvironmentCornell UniversityIthacaNew YorkUSA
| | - Wesley A. Larson
- U.S. Geological SurveyWisconsin Cooperative Fishery Research UnitCollege of Natural ResourcesUniversity of Wisconsin‐Stevens PointStevens PointWisconsinUSA
- National Oceanographic and Atmospheric AdministrationNational Marine Fisheries ServiceAlaska Fisheries Science CenterAuke Bay LaboratoriesJuneauAlaskaUSA
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19
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AlAjmi MF, Khan S, Choudhury A, Mohammad T, Noor S, Hussain A, Lu W, Eapen MS, Chimankar V, Hansbro PM, Sohal SS, Elasbali AM, Hassan MI. Impact of Deleterious Mutations on Structure, Function and Stability of Serum/Glucocorticoid Regulated Kinase 1: A Gene to Diseases Correlation. Front Mol Biosci 2021; 8:780284. [PMID: 34805284 PMCID: PMC8597711 DOI: 10.3389/fmolb.2021.780284] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 10/19/2021] [Indexed: 11/22/2022] Open
Abstract
Serum and glucocorticoid-regulated kinase 1 (SGK1) is a Ser/Thr protein kinase involved in regulating cell survival, growth, proliferation, and migration. Its elevated expression and dysfunction are reported in breast, prostate, hepatocellular, lung adenoma, and renal carcinomas. We have analyzed the SGK1 mutations to explore their impact at the sequence and structure level by utilizing state-of-the-art computational approaches. Several pathogenic and destabilizing mutations were identified based on their impact on SGK1 and analyzed in detail. Three amino acid substitutions, K127M, T256A, and Y298A, in the kinase domain of SGK1 were identified and incorporated structurally into original coordinates of SGK1 to explore their time evolution impact using all-atom molecular dynamic (MD) simulations for 200 ns. MD results indicate substantial conformational alterations in SGK1, thus its functional loss, particularly upon T256A mutation. This study provides meaningful insights into SGK1 dysfunction upon mutation, leading to disease progression, including cancer, and neurodegeneration.
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Affiliation(s)
- Mohamed F. AlAjmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Shama Khan
- Drug Discovery and Development Centre (H3D), University of Cape Town, Cape Town, South Africa
| | - Arunabh Choudhury
- Department of Computer Science, Jamia Millia Islamia, New Delhi, India
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Saba Noor
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Wenying Lu
- Respiratory Translational Research Group, Department of Laboratory Medicine, School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, TAS, Australia
| | - Mathew Suji Eapen
- Respiratory Translational Research Group, Department of Laboratory Medicine, School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, TAS, Australia
| | - Vrushali Chimankar
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, School of Life Sciences, Faculty of Science, Sydney, NSW, Australia
- Priority Research Centre for Healthy Lungs and Hunter Medical Research Institute, The University of Newcastle, Newcastle, NSW, Australia
| | - Philip M Hansbro
- Priority Research Centre for Healthy Lungs and Hunter Medical Research Institute, The University of Newcastle, Newcastle, NSW, Australia
| | - Sukhwinder Singh Sohal
- Respiratory Translational Research Group, Department of Laboratory Medicine, School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, TAS, Australia
| | - Abdelbaset Mohamed Elasbali
- Clinical Laboratory Science, College of Applied Medical Sciences-Qurayyat, Jouf University, Sakakah, Saudi Arabia
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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20
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Umair M, Khan S, Mohammad T, Shafie A, Anjum F, Islam A, Hassan MI. Impact of single amino acid substitution on the structure and function of TANK-binding kinase-1. J Cell Biochem 2021; 122:1475-1490. [PMID: 34237165 DOI: 10.1002/jcb.30070] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/26/2021] [Accepted: 05/31/2021] [Indexed: 12/14/2022]
Abstract
Tank-binding kinase 1 (TBK1) is a serine/threonine protein kinase involved in various signaling pathways and subsequently regulates cell proliferation, apoptosis, autophagy, antiviral and antitumor immunity. Dysfunction of TBK1 can cause many complex diseases, including autoimmunity, neurodegeneration, and cancer. This dysfunction of TBK1 may result from single amino acid substitutions and subsequent structural alterations. This study analyzed the effect of substituting amino acids on TBK1 structure, function, and subsequent disease using advanced computational methods and various tools. In the initial assessment, a total of 467 mutations were found to be deleterious. After that, in detailed structural and sequential analyses, 13 mutations were found to be pathogenic. Finally, based on the functional importance, two variants (K38D and S172A) of the TBK1 kinase domain were selected and studied in detail by utilizing all-atom molecular dynamics (MD) simulation for 200 ns. MD simulation, including correlation matrix and principal component analysis, helps to get deeper insights into the TBK1 structure at the atomic level. We observed a substantial change in variants' conformation, which may be possible for structural alteration and subsequent TBK1 dysfunction. However, substitution S172A shows a significant conformational change in TBK1 structure as compared to K38D. Thus, this study provides a structural basis to understand the effect of mutations on the kinase domain of TBK1 and its function associated with disease progression.
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Affiliation(s)
- Mohd Umair
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi, India
| | - Shama Khan
- Drug Discovery and Development Centre (H3D), University of Cape Town, Rondebosch, South Africa
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, India
| | - Alaa Shafie
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Farah Anjum
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, India
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21
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Wang XJ, Barrett SCH, Zhong L, Wu ZK, Li DZ, Wang H, Zhou W. The Genomic Selfing Syndrome Accompanies the Evolutionary Breakdown of Heterostyly. Mol Biol Evol 2021; 38:168-180. [PMID: 32761213 PMCID: PMC7782863 DOI: 10.1093/molbev/msaa199] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The evolutionary transition from outcrossing to selfing can have important genomic consequences. Decreased effective population size and the reduced efficacy of selection are predicted to play an important role in the molecular evolution of the genomes of selfing species. We investigated evidence for molecular signatures of the genomic selfing syndrome using 66 species of Primula including distylous (outcrossing) and derived homostylous (selfing) taxa. We complemented our comparative analysis with a microevolutionary study of P. chungensis, which is polymorphic for mating system and consists of both distylous and homostylous populations. We generated chloroplast and nuclear genomic data sets for distylous, homostylous, and distylous–homostylous species and identified patterns of nonsynonymous to synonymous divergence (dN/dS) and polymorphism (πN/πS) in species or lineages with contrasting mating systems. Our analysis of coding sequence divergence and polymorphism detected strongly reduced genetic diversity and heterozygosity, decreased efficacy of purifying selection, purging of large-effect deleterious mutations, and lower rates of adaptive evolution in samples from homostylous compared with distylous populations, consistent with theoretical expectations of the genomic selfing syndrome. Our results demonstrate that self-fertilization is a major driver of molecular evolutionary processes with genomic signatures of selfing evident in both old and relatively young homostylous populations.
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Affiliation(s)
- Xin-Jia Wang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Li Zhong
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Kun Wu
- Department of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou, China
| | - De-Zhu Li
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Hong Wang
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Wei Zhou
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.,Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
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22
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Johri P, Charlesworth B, Howell EK, Lynch M, Jensen JD. Revisiting the Notion of Deleterious Sweeps. Genetics 2021; 219:6298596. [PMID: 34125884 PMCID: PMC9101445 DOI: 10.1093/genetics/iyab094] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/08/2021] [Indexed: 11/14/2022] Open
Abstract
It has previously been shown that, conditional on its fixation, the time to fixation of a semi-dominant deleterious autosomal mutation in a randomly mating population is the same as that of an advantageous mutation. This result implies that deleterious mutations could generate selective sweep-like effects. Although their fixation probabilities greatly differ, the much larger input of deleterious relative to beneficial mutations suggests that this phenomenon could be important. We here examine how the fixation of mildly deleterious mutations affects levels and patterns of polymorphism at linked sites - both in the presence and absence of interference amongst deleterious mutations - and how this class of sites may contribute to divergence between-populations and species. We find that, while deleterious fixations are unlikely to represent a significant proportion of outliers in polymorphism-based genomic scans within populations, minor shifts in the frequencies of deleterious mutations can influence the proportions of private variants and the value of FST after a recent population split. As sites subject to deleterious mutations are necessarily found in functional genomic regions, interpretations in terms of recurrent positive selection may require reconsideration.
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Affiliation(s)
- Parul Johri
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, United States
| | - Brian Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - Emma K Howell
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, United States
| | - Michael Lynch
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, United States.,Center for Mechanisms of Evolution, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, United States
| | - Jeffrey D Jensen
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, United States
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23
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Cui R, Tyers AM, Malubhoy ZJ, Wisotsky S, Valdesalici S, Henriette E, Kosakovsky Pond SL, Valenzano DR. Ancestral transoceanic colonization and recent population reduction in a nonannual killifish from the Seychelles archipelago. Mol Ecol 2021; 30:3610-3623. [PMID: 33998095 DOI: 10.1111/mec.15982] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 04/29/2021] [Accepted: 05/10/2021] [Indexed: 12/28/2022]
Abstract
Whether freshwater fish colonize remote islands following tectonic or transoceanic dispersal remains an evolutionary puzzle. Integrating dating of known tectonic events with phylogenomics and current species distribution, we find that killifish species distribution is not explained by species dispersal by tectonic drift only. Investigating the colonization of a nonannual killifish (golden panchax, Pachypanchax playfairii) on the Seychelle islands, we found genetic support for transoceanic dispersal and experimentally discovered an adaptation to complete tolerance to seawater. At the macroevolutionary scale, despite their long-lasting isolation, nonannual golden panchax show stronger genome-wide purifying selection than annual killifishes from continental Africa. However, progressive decline in effective population size over a more recent timescale has probably led to the segregation of slightly deleterious mutations across golden panchax populations, which represents a potential threat for species preservation in the long term.
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Affiliation(s)
- Rongfeng Cui
- Max Planck Institute for Biology of Ageing, Cologne, Germany.,School of Ecology, Sun Yat-sen University, Guangzhou, China
| | | | | | - Sadie Wisotsky
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University, Temple, CA, USA
| | | | - Elvina Henriette
- Island Biodiversity Conservation Centre, University of Seychelles, Anse Royale, Mahe, Seychelles
| | - Sergei L Kosakovsky Pond
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University, Temple, CA, USA
| | - Dario Riccardo Valenzano
- Max Planck Institute for Biology of Ageing, Cologne, Germany.,CECAD, University of Cologne, Cologne, Germany
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24
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Habib I, Khan S, Mohammad T, Hussain A, Alajmi MF, Rehman T, Anjum F, Hassan MI. Impact of non-synonymous mutations on the structure and function of telomeric repeat binding factor 1. J Biomol Struct Dyn 2021; 40:9053-9066. [PMID: 33982644 DOI: 10.1080/07391102.2021.1922313] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Telomeric repeat binding factor 1 (TRF1) is one of the major components of the shelterin complex. It directly binds to the telomere and controls its function by regulating the telomerase acting on it. Several variations are reported in the TRF1 gene; some are associated with variety of diseases. Here, we have studied the structural and functional significance of these variations in the TRFH domain of TRF1. We have used cutting-edge computational methods such as SIFT, PolyPhen-2, PROVEAN, Mutation Assessor, mCSM, SDM, STRUM, MAESTRO, and DUET to predict the effects of 124 mutations in the TRFH domain of TRF1. Out of 124 mutations, we have identified 12 deleterious mutations with high confidence based on their prediction. To see the impact of the finally selected mutations on the structure and stability of TRF1, all-atom molecular dynamics (MD) simulations on TRF1-Wild type (WT), L79R and P150R mutants for 200 ns were carried out. A significant conformational change in the structure of the P150R mutant was observed. Our integrated computational study provides a comprehensive understanding of structural changes in TRF1 incurred due to the mutations and subsequent function, leading to the progression of many diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Insan Habib
- Department of Computer Science, Jamia Millia Islamia, New Delhi, India
| | - Shama Khan
- Drug Discovery and Development Centre (H3D), University of Cape Town, Rondebosch, South Africa
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed F Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Tabish Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Farah Anjum
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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25
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Takou M, Hämälä T, Koch EM, Steige KA, Dittberner H, Yant L, Genete M, Sunyaev S, Castric V, Vekemans X, Savolainen O, de Meaux J. Maintenance of Adaptive Dynamics and No Detectable Load in a Range-Edge Outcrossing Plant Population. Mol Biol Evol 2021; 38:1820-1836. [PMID: 33480994 PMCID: PMC8097302 DOI: 10.1093/molbev/msaa322] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
During range expansion, edge populations are expected to face increased genetic drift, which in turn can alter and potentially compromise adaptive dynamics, preventing the removal of deleterious mutations and slowing down adaptation. Here, we contrast populations of the European subspecies Arabidopsis lyrata ssp. petraea, which expanded its Northern range after the last glaciation. We document a sharp decline in effective population size in the range-edge population and observe that nonsynonymous variants segregate at higher frequencies. We detect a 4.9% excess of derived nonsynonymous variants per individual in the range-edge population, suggesting an increase of the genomic burden of deleterious mutations. Inference of the fitness effects of mutations and modeling of allele frequencies under the explicit demographic history of each population predicts a depletion of rare deleterious variants in the range-edge population, but an enrichment for fixed ones, consistent with the bottleneck effect. However, the demographic history of the range-edge population predicts a small net decrease in per-individual fitness. Consistent with this prediction, the range-edge population is not impaired in its growth and survival measured in a common garden experiment. We further observe that the allelic diversity at the self-incompatibility locus, which ensures strict outcrossing and evolves under negative frequency-dependent selection, has remained unchanged. Genomic footprints indicative of selective sweeps are broader in the Northern population but not less frequent. We conclude that the outcrossing species A. lyrata ssp. petraea shows a strong resilience to the effect of range expansion.
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Affiliation(s)
- Margarita Takou
- Institute of Botany, University of Cologne, Cologne, Germany
| | - Tuomas Hämälä
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Evan M Koch
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Kim A Steige
- Institute of Botany, University of Cologne, Cologne, Germany
| | | | - Levi Yant
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Mathieu Genete
- CNRS, UMR 8198 – Evo-Eco-Paleo, University of Lille, Lille, France
| | - Shamil Sunyaev
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Vincent Castric
- CNRS, UMR 8198 – Evo-Eco-Paleo, University of Lille, Lille, France
| | - Xavier Vekemans
- CNRS, UMR 8198 – Evo-Eco-Paleo, University of Lille, Lille, France
| | - Outi Savolainen
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
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26
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Abstract
Dogs and humans have coexisted together for thousands of years, but it was not until the Victorian Era that humans practiced selective breeding to produce the modern standards we see today. Strong artificial selection during the breed formation period has simplified the genetic architecture of complex traits and caused an enrichment of identity-by-descent (IBD) segments in the dog genome. This study demonstrates the value of IBD segments and utilizes them to infer the recent demography of canids, predict case-control status for complex traits, locate regions of the genome potentially linked to inbreeding depression, and to identify understudied breeds where there is potential to discover new disease-associated variants. Domestic dogs have experienced population bottlenecks, recent inbreeding, and strong artificial selection. These processes have simplified the genetic architecture of complex traits, allowed deleterious variation to persist, and increased both identity-by-descent (IBD) segments and runs of homozygosity (ROH). As such, dogs provide an excellent model for examining how these evolutionary processes influence disease. We assembled a dataset containing 4,414 breed dogs, 327 village dogs, and 380 wolves genotyped at 117,288 markers and data for clinical and morphological phenotypes. Breed dogs have an enrichment of IBD and ROH, relative to both village dogs and wolves, and we use these patterns to show that breed dogs have experienced differing severities of bottlenecks in their recent past. We then found that ROH burden is associated with phenotypes in breed dogs, such as lymphoma. We next test the prediction that breeds with greater ROH have more disease alleles reported in the Online Mendelian Inheritance in Animals (OMIA). Surprisingly, the number of causal variants identified correlates with the popularity of that breed rather than the ROH or IBD burden, suggesting an ascertainment bias in OMIA. Lastly, we use the distribution of ROH across the genome to identify genes with depletions of ROH as potential hotspots for inbreeding depression and find multiple exons where ROH are never observed. Our results suggest that inbreeding has played a large role in shaping genetic and phenotypic variation in dogs and that future work on understudied breeds may reveal new disease-causing variation.
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27
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Ferchaud AL, Leitwein M, Laporte M, Boivin-Delisle D, Bougas B, Hernandez C, Normandeau É, Thibault I, Bernatchez L. Adaptive and maladaptive genetic diversity in small populations: Insights from the Brook Charr (Salvelinus fontinalis) case study. Mol Ecol 2020; 29:3429-3445. [PMID: 33463857 DOI: 10.1111/mec.15566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022]
Abstract
Investigating the relative importance of neutral versus selective processes governing the accumulation of genetic variants is a key goal in both evolutionary and conservation biology. This is particularly true in the context of small populations, where genetic drift can counteract the effect of selection. Using Brook Charr (Salvelinus fontinalis) from Québec, Canada, as a case study, we investigated the importance of demographic versus selective processes governing the accumulation of both adaptive and maladaptive mutations in closed versus open and connected populations to assess gene flow effect. This was achieved by using 14,779 high-quality filtered SNPs genotyped among 1,416 fish representing 50 populations from three life history types: lacustrine (closed populations), riverine and anadromous (connected populations). Using the PROVEAN algorithm, we observed a considerable accumulation of putative deleterious mutations across populations. The absence of correlation between the occurrence of putatively beneficial or deleterious mutations and local recombination rate supports the hypothesis that genetic drift might be the main driver of the accumulation of such variants. However, despite a lower genetic diversity observed in lacustrine than in riverine or anadromous populations, lacustrine populations do not exhibit more deleterious mutations than the two other history types, suggesting that the negative effect of genetic drift in lacustrine populations may be mitigated by that of relaxed purifying selection. Moreover, we also identified genomic regions associated with anadromy, as well as an overrepresentation of transposable elements associated with variation in environmental variables, thus supporting the importance of transposable elements in adaptation.
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Affiliation(s)
- Anne-Laure Ferchaud
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Maeva Leitwein
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Martin Laporte
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Damien Boivin-Delisle
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Bérénice Bougas
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Cécilia Hernandez
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Éric Normandeau
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
| | - Isabel Thibault
- Direction de l'expertise Sur la Faune Aquatique, Ministère des Forêts, de la Faune et des Parcs du Québec, Québec, QC, Canada
| | - Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, Canada
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28
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Abstract
Reduction of fitness due to deleterious mutations imposes a limit to adaptive evolution. By characterizing features that influence this genetic load we may better understand constraints on responses to both natural and human-mediated selection. Here, using whole-genome, transcriptome, and methylome data from >600 Arabidopsis thaliana individuals, we set out to identify important features influencing selective constraint. Our analyses reveal that multiple factors underlie the accumulation of maladaptive mutations, including gene expression level, gene network connectivity, and gene-body methylation. We then focus on a feature with major effect, nucleotide composition. The ancestral vs. derived status of segregating alleles suggests that GC-biased gene conversion, a recombination-associated process that increases the frequency of G and C nucleotides regardless of their fitness effects, shapes sequence patterns in A. thaliana Through estimation of mutational effects, we present evidence that biased gene conversion hinders the purging of deleterious mutations and contributes to a genome-wide signal of decreased efficacy of selection. By comparing these results to two outcrossing relatives, Arabidopsis lyrata and Capsella grandiflora, we find that protein evolution in A. thaliana is as strongly affected by biased gene conversion as in the outcrossing species. Last, we perform simulations to show that natural levels of outcrossing in A. thaliana are sufficient to facilitate biased gene conversion despite increased homozygosity due to selfing. Together, our results show that even predominantly selfing taxa are susceptible to biased gene conversion, suggesting that it may constitute an important constraint to adaptation among plant species.
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Affiliation(s)
- Tuomas Hämälä
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Peter Tiffin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
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29
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Orsucci M, Milesi P, Hansen J, Girodolle J, Glémin S, Lascoux M. Shift in ecological strategy helps marginal populations of shepherd's purse ( Capsella bursa-pastoris) to overcome a high genetic load. Proc Biol Sci 2020; 287:20200463. [PMID: 32429810 PMCID: PMC7287375 DOI: 10.1098/rspb.2020.0463] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The outcome of species range expansion depends on the interplay of demographic, environmental and genetic factors. Self-fertilizing species usually show a higher invasive ability than outcrossers but selfing and bottlenecks during colonization also lead to an increased genetic load. The relationship between genomic and phenotypic characteristics of expanding populations has, hitherto, rarely been tested experimentally. We analysed how accessions of the shepherd's purse, Capsella bursa-pastoris, from the colonization front or from the core of the natural range performed under increasing density of competitors. First, accessions from the front showed a lower fitness than those from the core. Second, for all accessions, competitor density impacted negatively both vegetative growth and fruit production. However, despite their higher genetic load and lower absolute performances, accessions from the front were less affected by competition than accessions from the core. This seems to be due to phenotypic trade-offs and a shift in phenology that allow accessions from the front to avoid competition.
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Affiliation(s)
- Marion Orsucci
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Pascal Milesi
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,Science for Life Laboratory, Uppsala, Sweden
| | - Johanna Hansen
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Johanna Girodolle
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Sylvain Glémin
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,ECOBIO UMR 6553 CNRS University of Rennes 1, Rennes, France
| | - Martin Lascoux
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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30
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Hämälä T, Guiltinan MJ, Marden JH, Maximova SN, dePamphilis CW, Tiffin P. Gene Expression Modularity Reveals Footprints of Polygenic Adaptation in Theobroma cacao. Mol Biol Evol 2020; 37:110-123. [PMID: 31501906 DOI: 10.1093/molbev/msz206] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Separating footprints of adaptation from demography is challenging. When selection has acted on a single locus with major effect, this issue can be alleviated through signatures left by selective sweeps. However, as adaptation is often driven by small allele frequency shifts at many loci, studies focusing on single genes are able to identify only a small portion of genomic variants responsible for adaptation. In face of this challenge, we utilize coexpression information to search for signals of polygenetic adaptation in Theobroma cacao, a tropical tree species that is the source of chocolate. Using transcriptomics and a weighted correlation network analysis, we group genes with similar expression patterns into functional modules. We then ask whether modules enriched for specific biological processes exhibit cumulative effects of differential selection in the form of high FST and dXY between populations. Indeed, modules putatively involved in protein modification, flowering, and water transport show signs of polygenic adaptation even though individual genes that are members of those groups do not bear strong signatures of selection. Modeling of demography, background selection, and the effects of genomic features reveal that these patterns are unlikely to arise by chance. We also find that specific modules are enriched for signals of strong or relaxed purifying selection, with one module bearing signs of adaptive differentiation and an excess of deleterious mutations. Our results provide insight into polygenic adaptation and contribute to understanding of population structure, demographic history, and genome evolution in T. cacao.
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Affiliation(s)
- Tuomas Hämälä
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN
| | - Mark J Guiltinan
- Department of Plant Sciences, The Pennsylvania State University, University Park, PA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA
| | - James H Marden
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA.,Department of Biology, The Pennsylvania State University, University Park, PA
| | - Siela N Maximova
- Department of Plant Sciences, The Pennsylvania State University, University Park, PA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA
| | - Claude W dePamphilis
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA.,Department of Biology, The Pennsylvania State University, University Park, PA
| | - Peter Tiffin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN
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31
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Castellano D, Macià MC, Tataru P, Bataillon T, Munch K. Comparison of the Full Distribution of Fitness Effects of New Amino Acid Mutations Across Great Apes. Genetics 2019; 213:953-966. [PMID: 31488516 PMCID: PMC6827385 DOI: 10.1534/genetics.119.302494] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/29/2019] [Indexed: 12/31/2022] Open
Abstract
The distribution of fitness effects (DFE) is central to many questions in evolutionary biology. However, little is known about the differences in DFE between closely related species. We use >9000 coding genes orthologous one-to-one across great apes, gibbons, and macaques to assess the stability of the DFE across great apes. We use the unfolded site frequency spectrum of polymorphic mutations (n = 8 haploid chromosomes per population) to estimate the DFE. We find that the shape of the deleterious DFE is strikingly similar across great apes. We confirm that effective population size (Ne ) is a strong predictor of the strength of negative selection, consistent with the nearly neutral theory. However, we also find that the strength of negative selection varies more than expected given the differences in Ne between species. Across species, mean fitness effects of new deleterious mutations covaries with Ne , consistent with positive epistasis among deleterious mutations. We find that the strength of negative selection for the smallest populations, bonobos and western chimpanzees, is higher than expected given their Ne This may result from a more efficient purging of strongly deleterious recessive variants in these populations. Forward simulations confirm that these findings are not artifacts of the way we are inferring Ne and DFE parameters. All findings are replicated using only GC-conservative mutations, thereby confirming that GC-biased gene conversion is not affecting our conclusions.
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Affiliation(s)
- David Castellano
- Bioinformatics Research Centre, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Moisès Coll Macià
- Bioinformatics Research Centre, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Paula Tataru
- Bioinformatics Research Centre, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Thomas Bataillon
- Bioinformatics Research Centre, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Kasper Munch
- Bioinformatics Research Centre, Aarhus University, DK-8000 Aarhus C, Denmark
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32
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Plesnar-Bielak A, Sychta K, Gaczorek TS, Palka JK, Prus MA, Prokop ZM. Does operational sex ratio influence relative strength of purging selection in males versus females? J Evol Biol 2019; 33:80-88. [PMID: 31549754 DOI: 10.1111/jeb.13547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 09/13/2019] [Accepted: 09/19/2019] [Indexed: 11/29/2022]
Abstract
According to theory, sexual selection in males may efficiently purge mutation load of sexual populations, reducing or fully compensating 'the cost of males'. For this to occur, mutations not only need to be deleterious to both sexes, they also must affect males more than females. A frequently overlooked problem is that relative strength of selection on males versus females may vary between environments, with social conditions being particularly likely to affect selection in males and females differently. Here, we induced mutations in red flour beetles (Tribolium castaneum) and tested their effect in both sexes under three different operational sex ratios (1:2, 1:1 and 2:1). Induced mutations decreased fitness of both males and females, but their effect was not stronger in males. Surprisingly, operational sex ratio did not affect selection against deleterious mutations nor its relative strength in the sexes. Thus, our results show no support for the role of sexual selection in the evolutionary maintenance of sex.
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Affiliation(s)
| | - Karolina Sychta
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Tomasz S Gaczorek
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Joanna K Palka
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Monika A Prus
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Zofia M Prokop
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
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33
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Connallon T, Olito C, Dutoit L, Papoli H, Ruzicka F, Yong L. Local adaptation and the evolution of inversions on sex chromosomes and autosomes. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0423. [PMID: 30150221 DOI: 10.1098/rstb.2017.0423] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2018] [Indexed: 11/12/2022] Open
Abstract
Spatially varying selection with gene flow can favour the evolution of inversions that bind locally adapted alleles together, facilitate local adaptation and ultimately drive genomic divergence between species. Several studies have shown that the rates of spread and establishment of new inversions capturing locally adaptive alleles depend on a suite of evolutionary factors, including the strength of selection for local adaptation, rates of gene flow and recombination, and the deleterious mutation load carried by inversions. Because the balance of these factors is expected to differ between X (or Z) chromosomes and autosomes, opportunities for inversion evolution are likely to systematically differ between these genomic regions, though such scenarios have not been formally modelled. Here, we consider the evolutionary dynamics of X-linked and autosomal inversions in populations evolving at a balance between migration and local selection. We identify three factors that lead to asymmetric rates of X-linked and autosome inversion establishment: (1) sex-biased migration, (2) dominance of locally adapted alleles and (3) chromosome-specific deleterious mutation loads. This theory predicts an elevated rate of fixation, and depressed opportunities for polymorphism, for X-linked inversions. Our survey of data on the genomic distribution of polymorphic and fixed inversions supports both theoretical predictions.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Tim Connallon
- School of Biological Sciences, and Centre for Geometric Biology, Monash University, Clayton, 3800 Victoria, Australia
| | - Colin Olito
- School of Biological Sciences, and Centre for Geometric Biology, Monash University, Clayton, 3800 Victoria, Australia.,Department of Biology, Section for Evolutionary Ecology, Lund University, 22362 Lund, Sweden
| | - Ludovic Dutoit
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden.,Department of Zoology, University of Otago, 9054 Dunedin, New Zealand
| | - Homa Papoli
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
| | - Filip Ruzicka
- Research Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Lengxob Yong
- Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9FE, UK
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34
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Shaik NA, Banaganapalli B. Computational Molecular Phenotypic Analysis of PTPN22 (W620R), IL6R (D358A), and TYK2 (P1104A) Gene Mutations of Rheumatoid Arthritis. Front Genet 2019; 10:168. [PMID: 30899276 PMCID: PMC6416176 DOI: 10.3389/fgene.2019.00168] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/15/2019] [Indexed: 12/31/2022] Open
Abstract
Rheumatoid arthritis (RA) is a chronic autoimmune disorder of bone joints caused by the complex interplay between several factors like body physiology, the environment with genetic background. The recent meta-analysis of GWAS has expanded the total number of RA-associated loci to more than 100, out of which approximately ∼97% (98 variants) loci are located in non-coding regions, and the other ∼3% (3 variants) are in three different non-HLA genes, i.e., TYK2 (Prp1104Ala), IL6R (Asp358Ala), and PTPN22 (Trp620Arg). However, whether these variants prompt changes in the protein phenotype with regards to its stability, structure, and interaction with other molecules, remains unknown. Thus, we selected the three clinically pathogenic variants described above, as positive controls and applied diverse computational methods to scrutinize if those mutations cause changes in the protein phenotype. Both wild type and mutant protein structures of PTPN22 (W620R), IL6R (D358A), and TYK2 (P1104A) were modeled and studied for structural deviations. Furthermore, we have also studied the secondary structure characteristics, solvent accessibility and stability, and the molecular interaction deformities caused by the amino acid substitutions. We observed that simple nucleotide predictions of SIFT, PolyPhen, CADD and FATHMM yields mixed findings in screening the RA-missense variants which showed a ≥P-value threshold of 5 × 10-8 in genome wide association studies. However, structure-based analysis confirms that mutant structures shows subtle but significant changes at their core regions, but their functional domains seems to lose wild type like functional interaction. Our findings suggest that the multidirectional computational analysis of clinically potential RA-mutations could act as a primary screening step before undertaking functional biology assays.
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Affiliation(s)
- Noor Ahmad Shaik
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Babajan Banaganapalli
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
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Valluru R, Gazave EE, Fernandes SB, Ferguson JN, Lozano R, Hirannaiah P, Zuo T, Brown PJ, Leakey ADB, Gore MA, Buckler ES, Bandillo N. Deleterious Mutation Burden and Its Association with Complex Traits in Sorghum ( Sorghum bicolor). Genetics 2019; 211:1075-87. [PMID: 30622134 DOI: 10.1534/genetics.118.301742] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 12/22/2018] [Indexed: 11/18/2022] Open
Abstract
Sorghum (Sorghum bicolor (L.) Moench) is a major staple food cereal for millions of people worldwide. Valluru et al. identify putative deleterious mutations among ∼5.5M segregating variants of 229 diverse sorghum... Sorghum (Sorghum bicolor L.) is a major food cereal for millions of people worldwide. The sorghum genome, like other species, accumulates deleterious mutations, likely impacting its fitness. The lack of recombination, drift, and the coupling with favorable loci impede the removal of deleterious mutations from the genome by selection. To study how deleterious variants impact phenotypes, we identified putative deleterious mutations among ∼5.5 M segregating variants of 229 diverse biomass sorghum lines. We provide the whole-genome estimate of the deleterious burden in sorghum, showing that ∼33% of nonsynonymous substitutions are putatively deleterious. The pattern of mutation burden varies appreciably among racial groups. Across racial groups, the mutation burden correlated negatively with biomass, plant height, specific leaf area (SLA), and tissue starch content (TSC), suggesting that deleterious burden decreases trait fitness. Putatively deleterious variants explain roughly one-half of the genetic variance. However, there is only moderate improvement in total heritable variance explained for biomass (7.6%) and plant height (average of 3.1% across all stages). There is no advantage in total heritable variance for SLA and TSC. The contribution of putatively deleterious variants to phenotypic diversity therefore appears to be dependent on the genetic architecture of traits. Overall, these results suggest that incorporating putatively deleterious variants into genomic models slightly improves prediction accuracy because of extensive linkage. Knowledge of deleterious variants could be leveraged for sorghum breeding through either genome editing and/or conventional breeding that focuses on the selection of progeny with fewer deleterious alleles.
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Plekhanova E, Nuzhdin SV, Utkin LV, Samsonova MG. Prediction of deleterious mutations in coding regions of mammals with transfer learning. Evol Appl 2019; 12:18-28. [PMID: 30622632 PMCID: PMC6304693 DOI: 10.1111/eva.12607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/16/2018] [Indexed: 12/31/2022] Open
Abstract
The genomes of mammals contain thousands of deleterious mutations. It is important to be able to recognize them with high precision. In conservation biology, the small size of fragmented populations results in accumulation of damaging variants. Preserving animals with less damaged genomes could optimize conservation efforts. In breeding of farm animals, trade-offs between farm performance versus general fitness might be better avoided if deleterious mutations are well classified. In humans, the problem of such a precise classification has been successfully solved, in large part due to large databases of disease-causing mutations. However, this kind of information is very limited for other mammals. Here, we propose to better use information available on human mutations to enable classification of damaging mutations in other mammalian species. Specifically, we apply transfer learning-machine learning methods-improving small dataset for solving a focal problem (recognizing damaging mutations in our companion and farm animals) due to the use of much large datasets available for solving a related problem (recognizing damaging mutations in humans). We validate our tools using mouse and dog annotated datasets and obtain significantly better results in companion to the SIFT classifier. Then, we apply them to predict deleterious mutations in cattle genomewide dataset.
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Affiliation(s)
- Elena Plekhanova
- Peter the Great St. Petersburg Polytechnic UniversitySt. PetersburgRussia
| | - Sergey V. Nuzhdin
- Peter the Great St. Petersburg Polytechnic UniversitySt. PetersburgRussia
- Program Molecular and Computation BiologyDornsife College of Letters, Arts, and SciencesUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Lev V. Utkin
- Peter the Great St. Petersburg Polytechnic UniversitySt. PetersburgRussia
| | - Maria G. Samsonova
- Peter the Great St. Petersburg Polytechnic UniversitySt. PetersburgRussia
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Mooney JA, Huber CD, Service S, Sul JH, Marsden CD, Zhang Z, Sabatti C, Ruiz-Linares A, Bedoya G, Freimer N, Lohmueller KE. Understanding the Hidden Complexity of Latin American Population Isolates. Am J Hum Genet 2018; 103:707-726. [PMID: 30401458 PMCID: PMC6218714 DOI: 10.1016/j.ajhg.2018.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 09/26/2018] [Indexed: 12/12/2022] Open
Abstract
Most population isolates examined to date were founded from a single ancestral population. Consequently, there is limited knowledge about the demographic history of admixed population isolates. Here we investigate genomic diversity of recently admixed population isolates from Costa Rica and Colombia and compare their diversity to a benchmark population isolate, the Finnish. These Latin American isolates originated during the 16th century from admixture between a few hundred European males and Amerindian females, with a limited contribution from African founders. We examine whole-genome sequence data from 449 individuals, ascertained as families to build mutigenerational pedigrees, with a mean sequencing depth of coverage of approximately 36×. We find that Latin American isolates have increased genetic diversity relative to the Finnish. However, there is an increase in the amount of identity by descent (IBD) segments in the Latin American isolates relative to the Finnish. The increase in IBD segments is likely a consequence of a very recent and severe population bottleneck during the founding of the admixed population isolates. Furthermore, the proportion of the genome that falls within a long run of homozygosity (ROH) in Costa Rican and Colombian individuals is significantly greater than that in the Finnish, suggesting more recent consanguinity in the Latin American isolates relative to that seen in the Finnish. Lastly, we find that recent consanguinity increased the number of deleterious variants found in the homozygous state, which is relevant if deleterious variants are recessive. Our study suggests that there is no single genetic signature of a population isolate.
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Affiliation(s)
- Jazlyn A Mooney
- Department of Human Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Christian D Huber
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Susan Service
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jae Hoon Sul
- Department of Psychiatry and Biobehavioral Sciences, Semel Center for Informatics and Personalized Genomics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Clare D Marsden
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Zhongyang Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Chiara Sabatti
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA; Department of Statistics, Stanford University, Stanford, CA 94305, USA
| | - Andrés Ruiz-Linares
- Ministry of Education Key Laboratory of Contemporary Anthropology and Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200438, China; Aix-Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Gabriel Bedoya
- Genética Molecular (GENMOL), Universidad de Antioquia, Medellín, Colombia
| | - Nelson Freimer
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, 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 90095, USA.
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Kono TJY, Lei L, Shih CH, Hoffman PJ, Morrell PL, Fay JC. Comparative Genomics Approaches Accurately Predict Deleterious Variants in Plants. G3 (Bethesda) 2018; 8:3321-3329. [PMID: 30139765 PMCID: PMC6169392 DOI: 10.1534/g3.118.200563] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 08/10/2018] [Indexed: 12/11/2022]
Abstract
Recent advances in genome resequencing have led to increased interest in prediction of the functional consequences of genetic variants. Variants at phylogenetically conserved sites are of particular interest, because they are more likely than variants at phylogenetically variable sites to have deleterious effects on fitness and contribute to phenotypic variation. Numerous comparative genomic approaches have been developed to predict deleterious variants, but the approaches are nearly always assessed based on their ability to identify known disease-causing mutations in humans. Determining the accuracy of deleterious variant predictions in nonhuman species is important to understanding evolution, domestication, and potentially to improving crop quality and yield. To examine our ability to predict deleterious variants in plants we generated a curated database of 2,910 Arabidopsis thaliana mutants with known phenotypes. We evaluated seven approaches and found that while all performed well, their relative ranking differed from prior benchmarks in humans. We conclude that deleterious mutations can be reliably predicted in A. thaliana and likely other plant species, but that the relative performance of various approaches does not necessarily translate from one species to another.
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Affiliation(s)
- Thomas J Y Kono
- Department of Agronomy & Plant Genetics, University of Minnesota, St. Paul, MN 551085
| | - Li Lei
- Department of Agronomy & Plant Genetics, University of Minnesota, St. Paul, MN 551085
| | - Ching-Hua Shih
- Department of Genetics, Washington University, St. Louis, MO 63110
| | - Paul J Hoffman
- Department of Agronomy & Plant Genetics, University of Minnesota, St. Paul, MN 551085
| | - Peter L Morrell
- Department of Agronomy & Plant Genetics, University of Minnesota, St. Paul, MN 551085
| | - Justin C Fay
- Department of Genetics, Washington University, St. Louis, MO 63110
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Ferchaud A, Laporte M, Perrier C, Bernatchez L. Impact of supplementation on deleterious mutation distribution in an exploited salmonid. Evol Appl 2018; 11:1053-1065. [PMID: 30026797 PMCID: PMC6050184 DOI: 10.1111/eva.12660] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 01/03/2023] Open
Abstract
Deleterious mutations have important implications for the evolutionary trajectories of populations. While several studies recently investigated the dynamics of deleterious mutations in wild populations, no study has yet explored the fate of deleterious mutations in a context of populations managed by supplementation. Here, based on a dataset of nine wild and 15 supplemented Lake Trout populations genotyped at 4,982 single nucleotide polymorphisms (SNP)s by means of genotype by sequencing (GBS), we explored the effect of supplementation on the frequency of putatively deleterious variants. Three main findings are consequential for the management of fish populations. First, an increase in neutral genetic diversity in stocked populations compared with unstocked ones was observed. Second, putatively deleterious mutations were more likely to be found in unstocked than in stocked populations, suggesting a lower efficiency to purge deleterious mutations in unstocked lakes. Third, a population currently used as a major source for supplementation is characterized by several fixed putatively deleterious alleles. Therefore, other source populations with lower abundance of putatively deleterious mutations should be favored as sources of supplementation. We discuss management implications of our results, especially pertaining to the joint identification of neutral and deleterious mutations that could help refining the choice of source and sink populations for supplementation in order to maximize their evolutionary potential and to limit their mutation load.
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Affiliation(s)
- Anne‐Laure Ferchaud
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
| | - Martin Laporte
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
| | - Charles Perrier
- Centre d’Écologie Fonctionnelle et ÉvolutiveUnité Mixte de Recherche CNRS 5175Montpellier Cedex 5France
| | - Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecQCCanada
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Gladieux P, Ravel S, Rieux A, Cros-Arteil S, Adreit H, Milazzo J, Thierry M, Fournier E, Terauchi R, Tharreau D. Coexistence of Multiple Endemic and Pandemic Lineages of the Rice Blast Pathogen. mBio 2018; 9:e01806-17. [PMID: 29615506 DOI: 10.1128/mBio.01806-17] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The rice blast fungus Magnaporthe oryzae (syn., Pyricularia oryzae) is both a threat to global food security and a model for plant pathology. Molecular pathologists need an accurate understanding of the origins and line of descent of M. oryzae populations in order to identify the genetic and functional bases of pathogen adaptation and to guide the development of more effective control strategies. We used a whole-genome sequence analysis of samples from different times and places to infer details about the genetic makeup of M. oryzae from a global collection of isolates. Analyses of population structure identified six lineages within M. oryzae, including two pandemic on japonica and indica rice, respectively, and four lineages with more restricted distributions. Tip-dating calibration indicated that M. oryzae lineages separated about a millennium ago, long after the initial domestication of rice. The major lineage endemic to continental Southeast Asia displayed signatures of sexual recombination and evidence of DNA acquisition from multiple lineages. Tests for weak natural selection revealed that the pandemic spread of clonal lineages entailed an evolutionary “cost,” in terms of the accumulation of deleterious mutations. Our findings reveal the coexistence of multiple endemic and pandemic lineages with contrasting population and genetic characteristics within a widely distributed pathogen. The rice blast fungus Magnaporthe oryzae (syn., Pyricularia oryzae) is a textbook example of a rapidly adapting pathogen, and it is responsible for one of the most damaging diseases of rice. Improvements in our understanding of Magnaporthe oryzae’s diversity and evolution are required to guide the development of more effective control strategies. We used genome sequencing data for samples from around the world to infer the evolutionary history of M. oryzae. We found that M. oryzae diversified about 1,000 years ago, separating into six main lineages: two pandemic on japonica and indica rice, respectively, and four with more restricted distributions. We also found that a lineage endemic to continental Southeast Asia displayed signatures of sexual recombination and the acquisition of genetic material from multiple lineages. This work provides a population-level genomic framework for defining molecular markers for the control of rice blast and investigations of the molecular basis of differences in pathogenicity between M. oryzae lineages.
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Xu S, Van Tran K, Neupane S, Snyman M, Huynh TV, Sung W. Single-sperm sequencing reveals the accelerated mitochondrial mutation rate in male Daphnia pulex (Crustacea, Cladocera). Proc Biol Sci 2018; 284:rspb.2017.1548. [PMID: 28931740 DOI: 10.1098/rspb.2017.1548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/16/2017] [Indexed: 01/23/2023] Open
Abstract
Mutation rate in the nuclear genome differs between sexes, with males contributing more mutations than females to their offspring. The male-biased mutation rates in the nuclear genome is most likely to be driven by a higher number of cell divisions in spermatogenesis than in oogenesis, generating more opportunities for DNA replication errors. However, it remains unknown whether male-biased mutation rates are present in mitochondrial DNA (mtDNA). Although mtDNA is maternally inherited and male mtDNA mutation typically does not contribute to genetic variation in offspring, male mtDNA mutations are critical for male reproductive health. In this study, we measured male mtDNA mutation rate using publicly available whole-genome sequences of single sperm of the freshwater microcrustacean Daphnia pulex Using a stringent mutation detection pipeline, we found that the male mtDNA mutation rate is 3.32 × 10-6 per site per generation. All the detected mutations are heteroplasmic base substitutions, with 57% of mutations converting G/C to A/T nucleotides. Consistent with the male-biased mutation in the nuclear genome, the male mtDNA mutation rate in D. pulex is approximately 20 times higher than the female rate per generation. We propose that the elevated mutation rate per generation in male mtDNA is consistent with an increased number of cell divisions during male gametogenesis.
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Affiliation(s)
- Sen Xu
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Kenny Van Tran
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Swatantra Neupane
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Marelize Snyman
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Trung Viet Huynh
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Way Sung
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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Hough J, Wang W, Barrett SCH, Wright SI. Hill-Robertson Interference Reduces Genetic Diversity on a Young Plant Y-Chromosome. Genetics 2017; 207:685-95. [PMID: 28811388 DOI: 10.1534/genetics.117.300142] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 08/03/2017] [Indexed: 11/18/2022] Open
Abstract
X and Y chromosomes differ in effective population size (Ne ), rates of recombination, and exposure to natural selection, all of which can affect patterns of genetic diversity. On Y chromosomes with suppressed recombination, natural selection is expected to eliminate linked neutral variation, and lower the Ne of Y compared to X chromosomes or autosomes. However, female-biased sex ratios and high variance in male reproductive success can also reduce Y-linked Ne , making it difficult to infer the causes of low Y-diversity. Here, we investigate the factors affecting levels of polymorphism during sex chromosome evolution in the dioecious plant Rumexhastatulus (Polygonaceae). Strikingly, we find that neutral diversity for genes on the Y chromosome is, on average, 2.1% of the value for their X-linked homologs, corresponding to a chromosome-wide reduction of 93% compared to the standard neutral expectation. We demonstrate that the magnitude of this diversity loss is inconsistent with reduced male Ne caused by neutral processes. Instead, using forward simulations and estimates of the distribution of deleterious fitness effects, we show that Y chromosome diversity loss can be explained by purifying selection acting in aggregate over a large number of genetically linked sites. Simulations also suggest that our observed level of Y-diversity is consistent with the joint action of purifying and positive selection, but only for models in which there were fewer constrained sites than we empirically estimated. Given the relatively recent origin of R. hastatulus sex chromosomes, our results imply that Y-chromosome degeneration in the early stages may be largely driven by selective interference rather than by neutral genetic drift of silenced Y-linked genes.
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Abstract
The fixation of new deleterious mutations is analyzed for a randomly mating population of constant size with no environmental or demographic stochasticity. Mildly deleterious mutations are far more important in causing loss of fitness and eventual extinction than are lethal and semilethal mutations in populations with effective sizes, Ne , larger than a few individuals. If all mildly deleterious mutations have the same selection coefficient, s against heterozygotes and 2s against homozygotes, the mean time to extinction, t¯, is asymptotically proportional to e4Nes/Ne for 4Ne s > 1. Nearly neutral mutations pose the greatest risk of extinction for stable populations, because the magnitude of selection coefficient that minimizes t¯ is about ŝ = 0.4/Ne . The influence of variance in selection coefficients among mutations is analyzed assuming a gamma distribution of s, with mean s¯ and variance σs2. The mean time to extinction increases with variance in selection coefficients if s¯ is near ŝ, but can decrease greatly if s¯ is much larger than ŝ. For a given coefficient of variation of s, c=σs/s¯, the mean time to extinction is asymptotically proportional to Ne1+1/c2 for 4Nes¯>1. When s is exponentially distributed, (c = 1) t¯ is asymptotically proportional to Ne2. These results in conjunction with data on the rate and magnitude of mildly deleterious mutations in Drosophila melanogaster indicate that even moderately large populations, with effective sizes on the order of Ne = 103 , may incur a substantial risk of extinction from the fixation of new mutations.
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Affiliation(s)
- Russell Lande
- Department of Biology, University of Oregon, Eugene, Oregon, 97403-1210
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Kim BY, Huber CD, Lohmueller KE. Inference of the Distribution of Selection Coefficients for New Nonsynonymous Mutations Using Large Samples. Genetics 2017; 206:345-61. [PMID: 28249985 DOI: 10.1534/genetics.116.197145] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 02/14/2017] [Indexed: 12/23/2022] Open
Abstract
The distribution of fitness effects (DFE) has considerable importance in population genetics. To date, estimates of the DFE come from studies using a small number of individuals. Thus, estimates of the proportion of moderately to strongly deleterious new mutations may be unreliable because such variants are unlikely to be segregating in the data. Additionally, the true functional form of the DFE is unknown, and estimates of the DFE differ significantly between studies. Here we present a flexible and computationally tractable method, called Fit∂a∂i, to estimate the DFE of new mutations using the site frequency spectrum from a large number of individuals. We apply our approach to the frequency spectrum of 1300 Europeans from the Exome Sequencing Project ESP6400 data set, 1298 Danes from the LuCamp data set, and 432 Europeans from the 1000 Genomes Project to estimate the DFE of deleterious nonsynonymous mutations. We infer significantly fewer (0.38-0.84 fold) strongly deleterious mutations with selection coefficient |s| > 0.01 and more (1.24-1.43 fold) weakly deleterious mutations with selection coefficient |s| < 0.001 compared to previous estimates. Furthermore, a DFE that is a mixture distribution of a point mass at neutrality plus a gamma distribution fits better than a gamma distribution in two of the three data sets. Our results suggest that nearly neutral forces play a larger role in human evolution than previously thought.
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Savic Veselinovic M, Pavkovic-Lucic S, Kurbalija Novicic Z, Jelic M, Stamenkovic-Radak M, Andjelkovic M. Mating behavior as an indicator of quality of Drosophila subobscura males? Insect Sci 2017; 24:122-132. [PMID: 26235310 DOI: 10.1111/1744-7917.12257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/05/2015] [Indexed: 06/04/2023]
Abstract
According to current theoretical predictions, any deleterious mutations that reduce nonsexual fitness may have a negative influence on mating success. This means that sexual selection may remove deleterious mutations from the populations. Males of good genetic quality should be more successful in mating, compared to the males of lower genetic quality. As mating success is a condition dependent trait, large fractions of the genome may be a target of sexual selection and many behavioral traits are likely to be condition dependent. We manipulated the genetic quality of Drosophila subobscura males by inducing mutations with ionizing radiation and observed the effects of the obtained heterozygous mutations on male mating behavior: courtship occurrence, courtship latency, mating occurrence, latency to mating and duration of mating. We found possible effects of mutations. Females mated more frequently with male progeny of nonirradiated males and that these males courted females faster compared to the male progeny of irradiated males. Our findings indicate a possible important role of sexual selection in purging deleterious mutations.
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Affiliation(s)
| | | | | | - Mihailo Jelic
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Marina Stamenkovic-Radak
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Marko Andjelkovic
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
- Serbian Academy of Sciences and Arts, Belgrade, Serbia
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Bitocchi E, Rau D, Benazzo A, Bellucci E, Goretti D, Biagetti E, Panziera A, Laidò G, Rodriguez M, Gioia T, Attene G, McClean P, Lee RK, Jackson SA, Bertorelle G, Papa R. High Level of Nonsynonymous Changes in Common Bean Suggests That Selection under Domestication Increased Functional Diversity at Target Traits. Front Plant Sci 2017; 7:2005. [PMID: 28111584 PMCID: PMC5216878 DOI: 10.3389/fpls.2016.02005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 12/16/2016] [Indexed: 05/05/2023]
Abstract
Crop species have been deeply affected by the domestication process, and there have been many efforts to identify selection signatures at the genome level. This knowledge will help geneticists to better understand the evolution of organisms, and at the same time, help breeders to implement successful breeding strategies. Here, we focused on domestication in the Mesoamerican gene pool of Phaseolus vulgaris by sequencing 49 gene fragments from a sample of 45 P. vulgaris wild and domesticated accessions, and as controls, two accessions each of the closely related species Phaseolus coccineus and Phaseolus dumosus. An excess of nonsynonymous mutations within the domesticated germplasm was found. Our data suggest that the cost of domestication alone cannot explain fully this finding. Indeed, the significantly higher frequency of polymorphisms in the coding regions observed only in the domesticated plants (compared to noncoding regions), the fact that these mutations were mostly nonsynonymous and appear to be recently derived mutations, and the investigations into the functions of their relative genes (responses to biotic and abiotic stresses), support a scenario that involves new functional mutations selected for adaptation during domestication. Moreover, consistent with this hypothesis, selection analysis and the possibility to compare data obtained for the same genes in different studies of varying sizes, data types, and methodologies allowed us to identify four genes that were strongly selected during domestication. Each selection candidate is involved in plant resistance/tolerance to abiotic stresses, such as heat, drought, and salinity. Overall, our study suggests that domestication acted to increase functional diversity at target loci, which probably controlled traits related to expansion and adaptation to new agro-ecological growing conditions.
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Affiliation(s)
- Elena Bitocchi
- Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle MarcheAncona, Italy
| | - Domenico Rau
- Department of Agriculture, Università degli Studi di SassariSassari, Italy
| | - Andrea Benazzo
- Department of Life Sciences and Biotechnology, Università degli Studi di FerraraFerrara, Italy
| | - Elisa Bellucci
- Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle MarcheAncona, Italy
| | - Daniela Goretti
- Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle MarcheAncona, Italy
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversityUmeå, Sweden
| | - Eleonora Biagetti
- Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle MarcheAncona, Italy
| | - Alex Panziera
- Department of Life Sciences and Biotechnology, Università degli Studi di FerraraFerrara, Italy
| | - Giovanni Laidò
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Centro di Ricerca per la CerealicolturaFoggia, Italy
| | - Monica Rodriguez
- Department of Agriculture, Università degli Studi di SassariSassari, Italy
| | - Tania Gioia
- Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università degli Studi della BasilicataPotenza, Italy
| | - Giovanna Attene
- Department of Agriculture, Università degli Studi di SassariSassari, Italy
| | - Phillip McClean
- Department of Plant Sciences, North Dakota State UniversityFargo, ND, USA
| | - Rian K. Lee
- Department of Plant Sciences, North Dakota State UniversityFargo, ND, USA
| | - Scott A. Jackson
- Center for Applied Genetic Technologies, University of GeorgiaAthens, GA, USA
| | - Giorgio Bertorelle
- Department of Life Sciences and Biotechnology, Università degli Studi di FerraraFerrara, Italy
| | - Roberto Papa
- Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle MarcheAncona, Italy
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Abstract
Sexual reproduction leads to an alternation between haploid and diploid phases, whose relative length varies widely across taxa. Previous genetical models showed that diploid or haploid life cycles may be favored, depending on dominance interactions and on effective recombination rates. By contrast, niche differentiation between haploids and diploids may favor biphasic life cycles, in which development occurs in both phases. In this article, we explore the interplay between genetical and ecological factors, assuming that deleterious mutations affect the competitivity of individuals within their ecological niche and allowing different effects of mutations in haploids and diploids (including antagonistic selection). We show that selection on a modifier gene affecting the relative length of both phases can be decomposed into a direct selection term favoring the phase with the highest mean fitness (due to either ecological differences or differential effects of mutations) and an indirect selection term favoring the phase in which selection is more efficient. When deleterious alleles occur at many loci and in the presence of ecological differentiation between haploids and diploids, evolutionary branching often occurs and leads to the stable coexistence of alleles coding for haploid and diploid cycles, while temporal variations in niche sizes may stabilize biphasic cycles.
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48
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Abstract
Populations continually incur new mutations with fitness effects ranging from lethal to adaptive. While the distribution of fitness effects of new mutations is not directly observable, many mutations likely either have no effect on organismal fitness or are deleterious. Historically, it has been hypothesized that a population may carry many mildly deleterious variants as segregating variation, which reduces the mean absolute fitness of the population. Recent advances in sequencing technology and sequence conservation-based metrics for inferring the functional effect of a variant permit examination of the persistence of deleterious variants in populations. The issue of segregating deleterious variation is particularly important for crop improvement, because the demographic history of domestication and breeding allows deleterious variants to persist and reach moderate frequency, potentially reducing crop productivity. In this study, we use exome resequencing of 15 barley accessions and genome resequencing of 8 soybean accessions to investigate the prevalence of deleterious single nucleotide polymorphisms (SNPs) in the protein-coding regions of the genomes of two crops. We conclude that individual cultivars carry hundreds of deleterious SNPs on average, and that nonsense variants make up a minority of deleterious SNPs. Our approach identifies known phenotype-altering variants as deleterious more frequently than the genome-wide average, suggesting that putatively deleterious variants are likely to affect phenotypic variation. We also report the implementation of a SNP annotation tool BAD_Mutations that makes use of a likelihood ratio test based on alignment of all currently publicly available Angiosperm genomes.
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Affiliation(s)
- Thomas J Y Kono
- Department of Agronomy and Plant Genetics, University of Minnesota
| | - Fengli Fu
- Department of Agronomy and Plant Genetics, University of Minnesota
| | - Mohsen Mohammadi
- Department of Agronomy and Plant Genetics, University of Minnesota Department of Agronomy, Purdue University
| | - Paul J Hoffman
- Department of Agronomy and Plant Genetics, University of Minnesota
| | - Chaochih Liu
- Department of Agronomy and Plant Genetics, University of Minnesota
| | - Robert M Stupar
- Department of Agronomy and Plant Genetics, University of Minnesota
| | - Kevin P Smith
- Department of Agronomy and Plant Genetics, University of Minnesota
| | - Peter Tiffin
- Department of Plant Biology, University of Minnesota
| | | | - Peter L Morrell
- Department of Agronomy and Plant Genetics, University of Minnesota
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49
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Arunkumar R, Maddison TI, Barrett SCH, Wright SI. Recent mating-system evolution in Eichhornia is accompanied by cis-regulatory divergence. New Phytol 2016; 211:697-707. [PMID: 26990568 DOI: 10.1111/nph.13918] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/30/2016] [Indexed: 06/05/2023]
Abstract
The evolution of predominant self-fertilization from cross-fertilization in plants is accompanied by diverse changes to morphology, ecology and genetics, some of which likely result from regulatory changes in gene expression. We examined changes in gene expression during early stages in the transition to selfing in populations of animal-pollinated Eichhornia paniculata with contrasting mating patterns. We crossed plants from outcrossing and selfing populations and tested for the presence of allele-specific expression (ASE) in floral buds and leaf tissue of F1 offspring, indicative of cis-regulatory changes. We identified 1365 genes exhibiting ASE in floral buds and leaf tissue. These genes preferentially expressed alleles from outcrossing parents. Moreover, we found evidence that genes exhibiting ASE had a greater nonsynonymous diversity compared to synonymous diversity in the selfing parents. Our results suggest that the transition from outcrossing to high rates of self-fertilization may have the potential to shape the cis-regulatory genomic landscape of angiosperm species, but that the changes in ASE may be moderate, particularly during the early stages of this transition.
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Affiliation(s)
- Ramesh Arunkumar
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Teresa I Maddison
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
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50
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Zhao L, Charlesworth B. Resolving the Conflict Between Associative Overdominance and Background Selection. Genetics 2016; 203:1315-34. [PMID: 27182952 DOI: 10.1534/genetics.116.188912] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/25/2016] [Indexed: 11/18/2022] Open
Abstract
In small populations, genetic linkage between a polymorphic neutral locus and loci subject to selection, either against partially recessive mutations or in favor of heterozygotes, may result in an apparent selective advantage to heterozygotes at the neutral locus (associative overdominance) and a retardation of the rate of loss of variability by genetic drift at this locus. In large populations, selection against deleterious mutations has previously been shown to reduce variability at linked neutral loci (background selection). We describe analytical, numerical, and simulation studies that shed light on the conditions under which retardation vs. acceleration of loss of variability occurs at a neutral locus linked to a locus under selection. We consider a finite, randomly mating population initiated from an infinite population in equilibrium at a locus under selection. With mutation and selection, retardation occurs only when S, the product of twice the effective population size and the selection coefficient, is of order 1. With S >> 1, background selection always causes an acceleration of loss of variability. Apparent heterozygote advantage at the neutral locus is, however, always observed when mutations are partially recessive, even if there is an accelerated rate of loss of variability. With heterozygote advantage at the selected locus, loss of variability is nearly always retarded. The results shed light on experiments on the loss of variability at marker loci in laboratory populations and on the results of computer simulations of the effects of multiple selected loci on neutral variability.
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