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Zhang T, Peng W, Xiao H, Cao S, Chen Z, Su X, Luo Y, Liu Z, Peng Y, Yang X, Jiang GF, Xu X, Ma Z, Zhou Y. Population genomics highlights structural variations in local adaptation to saline coastal environments in woolly grape. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024. [PMID: 38578160 DOI: 10.1111/jipb.13653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 03/04/2024] [Indexed: 04/06/2024]
Abstract
Structural variations (SVs) are a feature of plant genomes that has been largely unexplored despite their significant impact on plant phenotypic traits and local adaptation to abiotic and biotic stress. In this study, we employed woolly grape (Vitis retordii), a species native to the tropical and subtropical regions of East Asia with both coastal and inland habitats, as a valuable model for examining the impact of SVs on local adaptation. We assembled a haplotype-resolved chromosomal reference genome for woolly grape, and conducted population genetic analyses based on whole-genome sequencing (WGS) data from coastal and inland populations. The demographic analyses revealed recent bottlenecks in all populations and asymmetric gene flow from the inland to the coastal population. In total, 1,035 genes associated with plant adaptive regulation for salt stress, radiation, and environmental adaptation were detected underlying local selection by SVs and SNPs in the coastal population, of which 37.29% and 65.26% were detected by SVs and SNPs, respectively. Candidate genes such as FSD2, RGA1, and AAP8 associated with salt tolerance were found to be highly differentiated and selected during the process of local adaptation to coastal habitats in SV regions. Our study highlights the importance of SVs in local adaptation; candidate genes related to salt stress and climatic adaptation to tropical and subtropical environments are important genomic resources for future breeding programs of grapevine and its rootstocks.
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Affiliation(s)
- Tianhao Zhang
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, College of Forestry, Guangxi University, Nanning, 530004, China
- College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wenjing Peng
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
- Guangxi Key Laboratory of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Hua Xiao
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Shuo Cao
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
- Key Laboratory of Horticultural Plant Biology Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhuyifu Chen
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Xiangnian Su
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, College of Forestry, Guangxi University, Nanning, 530004, China
| | - Yuanyuan Luo
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China
| | - Zhongjie Liu
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Yanling Peng
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Xiping Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
- Guangxi Key Laboratory of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Guo-Feng Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, College of Forestry, Guangxi University, Nanning, 530004, China
| | - Xiaodong Xu
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Zhiyao Ma
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Yongfeng Zhou
- National Key Laboratory of Tropical Crop Breeding, Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
- National Key Laboratory of Tropical Crop Breeding, Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
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Harris M, Kim BY, Garud N. Enrichment of hard sweeps on the X chromosome compared to autosomes in six Drosophila species. Genetics 2024; 226:iyae019. [PMID: 38366786 PMCID: PMC10990427 DOI: 10.1093/genetics/iyae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 02/18/2024] Open
Abstract
The X chromosome, being hemizygous in males, is exposed one-third of the time increasing the visibility of new mutations to natural selection, potentially leading to different evolutionary dynamics than autosomes. Recently, we found an enrichment of hard selective sweeps over soft selective sweeps on the X chromosome relative to the autosomes in a North American population of Drosophila melanogaster. To understand whether this enrichment is a universal feature of evolution on the X chromosome, we analyze diversity patterns across 6 commonly studied Drosophila species. We find an increased proportion of regions with steep reductions in diversity and elevated homozygosity on the X chromosome compared to autosomes. To assess if these signatures are consistent with positive selection, we simulate a wide variety of evolutionary scenarios spanning variations in demography, mutation rate, recombination rate, background selection, hard sweeps, and soft sweeps and find that the diversity patterns observed on the X are most consistent with hard sweeps. Our findings highlight the importance of sex chromosomes in driving evolutionary processes and suggest that hard sweeps have played a significant role in shaping diversity patterns on the X chromosome across multiple Drosophila species.
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Affiliation(s)
- Mariana Harris
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Bernard Y Kim
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Nandita Garud
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Human Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
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Zhang R, Mu C, Chang L, Shen X, Bu Z, Yang M, Fu S, Tang Q, Liu P, Yang X. Whole-Genome Sequencing for Identifying Candidate Genes Related to the Special Phenotypes of the Taihu Dianzi Pigeon. Animals (Basel) 2024; 14:1047. [PMID: 38612286 PMCID: PMC11011069 DOI: 10.3390/ani14071047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 02/28/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
The Taihu Dianzi pigeon is a breed native to China, and its special piebalding, crest, and polydactyly phenotypes are the result of artificial and natural selection. Here, we analyzed the genetic differences among three kinds of pigeons with different phenotypes at the genomic level. A selective sweep was conducted based on the fixation index (FST) and nucleotide diversity (π) ratio, and the results revealed that MC1R was related to the formation of the distinctive piebalding of the Taihu Dianzi pigeon. Combined with the results of genome-wide association studies, we identified candidate genes associated with the crest (SMYD and STOX2) and polydactyly (SLC52A3 and ANGPT4). The candidate genes identified in this study and their variants may be useful for understanding the genetic mechanism underlying the special phenotypes of the Taihu Dianzi pigeon. This study provides new insights into the genetic factors that may influence the formation of the special piebalding, crest, and polydactyly characteristics in pigeons.
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Affiliation(s)
- Rui Zhang
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Chunyu Mu
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Lingling Chang
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Xinyue Shen
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Zhu Bu
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Mingjun Yang
- Henan Tiancheng Pigeon Industry Co., Ltd., Pingdingshan 462513, China; (M.Y.); (P.L.); (X.Y.)
| | - Shengyong Fu
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Qingping Tang
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences Poultry Institute, Yangzhou 225100, China; (R.Z.); (C.M.); (L.C.); (X.S.); (Z.B.); (S.F.)
| | - Peiyao Liu
- Henan Tiancheng Pigeon Industry Co., Ltd., Pingdingshan 462513, China; (M.Y.); (P.L.); (X.Y.)
| | - Xiaoming Yang
- Henan Tiancheng Pigeon Industry Co., Ltd., Pingdingshan 462513, China; (M.Y.); (P.L.); (X.Y.)
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4
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Thom G, Moreira LR, Batista R, Gehara M, Aleixo A, Smith BT. Genomic Architecture Predicts Tree Topology, Population Structuring, and Demographic History in Amazonian Birds. Genome Biol Evol 2024; 16:evae002. [PMID: 38236173 PMCID: PMC10823491 DOI: 10.1093/gbe/evae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/26/2023] [Accepted: 12/12/2023] [Indexed: 01/19/2024] Open
Abstract
Geographic barriers are frequently invoked to explain genetic structuring across the landscape. However, inferences on the spatial and temporal origins of population variation have been largely limited to evolutionary neutral models, ignoring the potential role of natural selection and intrinsic genomic processes known as genomic architecture in producing heterogeneity in differentiation across the genome. To test how variation in genomic characteristics (e.g. recombination rate) impacts our ability to reconstruct general patterns of differentiation between species that cooccur across geographic barriers, we sequenced the whole genomes of multiple bird populations that are distributed across rivers in southeastern Amazonia. We found that phylogenetic relationships within species and demographic parameters varied across the genome in predictable ways. Genetic diversity was positively associated with recombination rate and negatively associated with species tree support. Gene flow was less pervasive in genomic regions of low recombination, making these windows more likely to retain patterns of population structuring that matched the species tree. We further found that approximately a third of the genome showed evidence of selective sweeps and linked selection, skewing genome-wide estimates of effective population sizes and gene flow between populations toward lower values. In sum, we showed that the effects of intrinsic genomic characteristics and selection can be disentangled from neutral processes to elucidate spatial patterns of population differentiation.
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Affiliation(s)
- Gregory Thom
- Department of Ornithology, American Museum of Natural History, New York, NY, USA
- Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Lucas Rocha Moreira
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Department of Vertebrate Genomics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Romina Batista
- Programa de Coleções Biológicas, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
- School of Science, Engineering and Environment, University of Salford, Manchester, UK
| | - Marcelo Gehara
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ, USA
| | - Alexandre Aleixo
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
- Department of Environmental Genomics, Instituto Tecnológico Vale, Belém, Brazil
| | - Brian Tilston Smith
- Department of Ornithology, American Museum of Natural History, New York, NY, USA
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5
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Harris M, Kim B, Garud N. Enrichment of hard sweeps on the X chromosome compared to autosomes in six Drosophila species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.21.545888. [PMID: 38106201 PMCID: PMC10723260 DOI: 10.1101/2023.06.21.545888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The X chromosome, being hemizygous in males, is exposed one third of the time increasing the visibility of new mutations to natural selection, potentially leading to different evolutionary dynamics than autosomes. Recently, we found an enrichment of hard selective sweeps over soft selective sweeps on the X chromosome relative to the autosomes in a North American population of Drosophila melanogaster. To understand whether this enrichment is a universal feature of evolution on the X chromosome, we analyze diversity patterns across six commonly studied Drosophila species. We find an increased proportion of regions with steep reductions in diversity and elevated homozygosity on the X chromosome compared to autosomes. To assess if these signatures are consistent with positive selection, we simulate a wide variety of evolutionary scenarios spanning variations in demography, mutation rate, recombination rate, background selection, hard sweeps, and soft sweeps, and find that the diversity patterns observed on the X are most consistent with hard sweeps. Our findings highlight the importance of sex chromosomes in driving evolutionary processes and suggest that hard sweeps have played a significant role in shaping diversity patterns on the X chromosome across multiple Drosophila species.
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Affiliation(s)
- Mariana Harris
- Department of Computational Medicine, University of California Los Angeles, Los Angeles California, United States of America
| | - Bernard Kim
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Nandita Garud
- Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles California, United States of America
- Department of Human Genetics, University of California, Los Angeles, California, United States of America
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6
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Lukic B, Curik I, Drzaic I, Galić V, Shihabi M, Vostry L, Cubric-Curik V. Genomic signatures of selection, local adaptation and production type characterisation of East Adriatic sheep breeds. J Anim Sci Biotechnol 2023; 14:142. [PMID: 37932811 PMCID: PMC10626677 DOI: 10.1186/s40104-023-00936-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 09/04/2023] [Indexed: 11/08/2023] Open
Abstract
BACKGROUND The importance of sheep breeding in the Mediterranean part of the eastern Adriatic has a long tradition since its arrival during the Neolithic migrations. Sheep production system is extensive and generally carried out in traditional systems without intensive systematic breeding programmes for high uniform trait production (carcass, wool and milk yield). Therefore, eight indigenous Croatian sheep breeds from eastern Adriatic treated here as metapopulation (EAS), are generally considered as multipurpose breeds (milk, meat and wool), not specialised for a particular type of production, but known for their robustness and resistance to certain environmental conditions. Our objective was to identify genomic regions and genes that exhibit patterns of positive selection signatures, decipher their biological and productive functionality, and provide a "genomic" characterization of EAS adaptation and determine its production type. RESULTS We identified positive selection signatures in EAS using several methods based on reduced local variation, linkage disequilibrium and site frequency spectrum (eROHi, iHS, nSL and CLR). Our analyses identified numerous genomic regions and genes (e.g., desmosomal cadherin and desmoglein gene families) associated with environmental adaptation and economically important traits. Most candidate genes were related to meat/production and health/immune response traits, while some of the candidate genes discovered were important for domestication and evolutionary processes (e.g., HOXa gene family and FSIP2). These results were also confirmed by GO and QTL enrichment analysis. CONCLUSIONS Our results contribute to a better understanding of the unique adaptive genetic architecture of EAS and define its productive type, ultimately providing a new opportunity for future breeding programmes. At the same time, the numerous genes identified will improve our understanding of ruminant (sheep) robustness and resistance in the harsh and specific Mediterranean environment.
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Affiliation(s)
- Boris Lukic
- Faculty of Agrobiotechnical Sciences Osijek, J.J, Strossmayer University of Osijek, Vladimira Preloga 1, 31000, Osijek, Croatia.
| | - Ino Curik
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetošimunska Cesta 25, 10000, Zagreb, Croatia.
| | - Ivana Drzaic
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
| | - Vlatko Galić
- Department of Maize Breeding and Genetics, Agricultural Institute Osijek, Južno predgrađe 17, 31000, Osijek, Croatia
| | - Mario Shihabi
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
| | - Luboš Vostry
- Czech University of Life Sciences Prague, Kamýcká 129, 165 00, Praque, Czech Republic
| | - Vlatka Cubric-Curik
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetošimunska Cesta 25, 10000, Zagreb, Croatia
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Feng J, Zhu W, Shi H, Peng D, Zang L, Wang Y, ZhaXi L, BaiMa J, Amevor FK, Wang X, Ma X, Zhao X. Analysis of the Selection Signal of the Tibetan Black Chicken Genome Based on Whole-Genome Sequencing. Genes (Basel) 2023; 14:1672. [PMID: 37761812 PMCID: PMC10531317 DOI: 10.3390/genes14091672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND The Tibetan chicken has adapted well to high altitudes genetically after its long-term habitation in the plateau. In this study, we analyzed the selection signal of Tibetan black chickens (TBCs) and discovered genes associated with the characteristics of germplasm. METHODS Whole-genome sequencing (WGS) was used to identify the single-nucleotide polymorphism (SNP) markers and genetic structures in the genome of Tibetan black chickens. Further, we performed a comparative population genomics analysis between the genomic data obtained in this present study and the genomic data for five wild red jungle fowls (RJFs) accessed from the NCBI database (GenBank accession number PRJNA241474). Thereafter, the Fst and Pi selections were used to identify genes under positive selection in the Tibetan black chicken genome. RESULTS A total of 9,490,690 SNPs were identified in the Tibetan black chickens. In addition, the results from the gene ontology (GO) analysis showed that 732 genes of TBCs were enriched in a total of 210 GO terms with specific molecular functions such as regulation of cellular catabolic process, the MAPK signaling pathway, regulation of ion transport, growth, morphogenesis and lung alveolus development which may provide a better mechanism to facilitate oxygen transport and utilization in TBCs. Moreover, the results from the KEGG analysis showed that 732 genes of the TBCs were significantly enriched in the calcium signaling pathway, circadian entrainment (ADCY1, GNG7 and PER3), oxytocin signaling pathway and pathways of multiple neurodegeneration diseases. In addition, the CD86 antigen (CD86) was identified as a gene associated with the immune response in chickens. It was also revealed that genes such as TRIT1, HPCAL4, NT5C1A and HEYL were discovered under selection in Tibetan black chickens on chromosome 23. These genes may be related to the local adaptive characteristics of Tibetan black chickens, for instance, NT5C1A and HEYL may be involved in the high-altitude adaption of oxygen delivery in Tibetan black chickens. CONCLUSIONS In summary, we found that selection mainly affects the disease resistance and cold acclimatization of Tibetan black chickens. Hence, these results may provide important genetic information for the evolution and breeding of Tibetan black chickens.
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Affiliation(s)
- Jing Feng
- Institute of Animal Husbandry and Veterinary Medicine, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, China; (H.S.); (D.P.); (Y.W.); (X.M.)
- Key Laboratory of Animal Genetics and Breeding on Tibetan Plateau, Ministry of Agriculture and Rural Affairs, Lhasa 850009, China
| | - Wei Zhu
- State Key Laboratory of Swine and Poultry Breeding Industry, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (W.Z.); (F.K.A.)
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Hairen Shi
- Institute of Animal Husbandry and Veterinary Medicine, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, China; (H.S.); (D.P.); (Y.W.); (X.M.)
- College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Da Peng
- Institute of Animal Husbandry and Veterinary Medicine, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, China; (H.S.); (D.P.); (Y.W.); (X.M.)
| | - Lei Zang
- Institute of Animal Husbandry and Veterinary Medicine, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, China; (H.S.); (D.P.); (Y.W.); (X.M.)
| | - Yan Wang
- Institute of Animal Husbandry and Veterinary Medicine, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, China; (H.S.); (D.P.); (Y.W.); (X.M.)
| | - Luobu ZhaXi
- Shannan Longzi County Agriculture and Animal Husbandry Comprehensive Service Center, Shannan 856600, China (J.B.)
| | - Jiancai BaiMa
- Shannan Longzi County Agriculture and Animal Husbandry Comprehensive Service Center, Shannan 856600, China (J.B.)
| | - Felix Kwame Amevor
- State Key Laboratory of Swine and Poultry Breeding Industry, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (W.Z.); (F.K.A.)
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiaoqi Wang
- Agriculture and Animal Husbandry Comprehensive Service Center of Lazi County, Shigatse 858100, China;
| | - Xueying Ma
- Institute of Animal Husbandry and Veterinary Medicine, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, China; (H.S.); (D.P.); (Y.W.); (X.M.)
| | - Xiaoling Zhao
- State Key Laboratory of Swine and Poultry Breeding Industry, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (W.Z.); (F.K.A.)
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
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Shang H, Field DL, Paun O, Rendón-Anaya M, Hess J, Vogl C, Liu J, Ingvarsson PK, Lexer C, Leroy T. Drivers of genomic landscapes of differentiation across a Populus divergence gradient. Mol Ecol 2023; 32:4348-4361. [PMID: 37271855 DOI: 10.1111/mec.17034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/20/2023] [Accepted: 05/23/2023] [Indexed: 06/06/2023]
Abstract
Speciation, the continuous process by which new species form, is often investigated by looking at the variation of nucleotide diversity and differentiation across the genome (hereafter genomic landscapes). A key challenge lies in how to determine the main evolutionary forces at play shaping these patterns. One promising strategy, albeit little used to date, is to comparatively investigate these genomic landscapes as progression through time by using a series of species pairs along a divergence gradient. Here, we resequenced 201 whole-genomes from eight closely related Populus species, with pairs of species at different stages along the divergence gradient to learn more about speciation processes. Using population structure and ancestry analyses, we document extensive introgression between some species pairs, especially those with parapatric distributions. We further investigate genomic landscapes, focusing on within-species (i.e. nucleotide diversity and recombination rate) and among-species (i.e. relative and absolute divergence) summary statistics of diversity and divergence. We observe relatively conserved patterns of genomic divergence across species pairs. Independent of the stage across the divergence gradient, we find support for signatures of linked selection (i.e. the interaction between natural selection and genetic linkage) in shaping these genomic landscapes, along with gene flow and standing genetic variation. We highlight the importance of investigating genomic patterns on multiple species across a divergence gradient and discuss prospects to better understand the evolutionary forces shaping the genomic landscapes of diversity and differentiation.
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Affiliation(s)
- Huiying Shang
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
- Xi'an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi'an, China
| | - David L Field
- School of Science, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Martha Rendón-Anaya
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Jaqueline Hess
- Helmholtz Centre for Environmental Research, Halle (Saale), Germany
| | - Claus Vogl
- Department of Biomedical Sciences, Vetmeduni Vienna, Vienna, Austria
| | - Jianquan Liu
- Key Laboratory for Bio-resources and Eco-environment, College of Life Science, Sichuan University, Chengdu, China
| | - Pär K Ingvarsson
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Thibault Leroy
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- GenPhySE, INRAE, INP, ENVT, Université de Toulouse, Castanet-Tolosan, France
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Whitehouse LS, Schrider DR. Timesweeper: accurately identifying selective sweeps using population genomic time series. Genetics 2023; 224:iyad084. [PMID: 37157914 PMCID: PMC10324941 DOI: 10.1093/genetics/iyad084] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 07/25/2022] [Accepted: 04/25/2023] [Indexed: 05/10/2023] Open
Abstract
Despite decades of research, identifying selective sweeps, the genomic footprints of positive selection, remains a core problem in population genetics. Of the myriad methods that have been developed to tackle this task, few are designed to leverage the potential of genomic time-series data. This is because in most population genetic studies of natural populations, only a single period of time can be sampled. Recent advancements in sequencing technology, including improvements in extracting and sequencing ancient DNA, have made repeated samplings of a population possible, allowing for more direct analysis of recent evolutionary dynamics. Serial sampling of organisms with shorter generation times has also become more feasible due to improvements in the cost and throughput of sequencing. With these advances in mind, here we present Timesweeper, a fast and accurate convolutional neural network-based tool for identifying selective sweeps in data consisting of multiple genomic samplings of a population over time. Timesweeper analyzes population genomic time-series data by first simulating training data under a demographic model appropriate for the data of interest, training a one-dimensional convolutional neural network on said simulations, and inferring which polymorphisms in this serialized data set were the direct target of a completed or ongoing selective sweep. We show that Timesweeper is accurate under multiple simulated demographic and sampling scenarios, identifies selected variants with high resolution, and estimates selection coefficients more accurately than existing methods. In sum, we show that more accurate inferences about natural selection are possible when genomic time-series data are available; such data will continue to proliferate in coming years due to both the sequencing of ancient samples and repeated samplings of extant populations with faster generation times, as well as experimentally evolved populations where time-series data are often generated. Methodological advances such as Timesweeper thus have the potential to help resolve the controversy over the role of positive selection in the genome. We provide Timesweeper as a Python package for use by the community.
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Affiliation(s)
- Logan S Whitehouse
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Daniel R Schrider
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA
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10
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Zang C, Wang X, Cheng P, Liu L, Guo X, Wang H, Lou Z, Lei J, Wang W, Wang Y, Gong M, Liu H. Evaluation of the evolutionary genetics and population structure of Culex pipiens pallens in Shandong province, China based on knockdown resistance (kdr) mutations and the mtDNA-COI gene. BMC Genomics 2023; 24:145. [PMID: 36964519 PMCID: PMC10039558 DOI: 10.1186/s12864-023-09243-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/11/2023] [Indexed: 03/26/2023] Open
Abstract
BACKGROUND Mosquitoes are important vectors for a range of diseases, contributing to high rates of morbidity and mortality in the human population. Culex pipiens pallens is dominant species of Culex mosquito in northern China and a major vector for both West Nile virus and Bancroftian filariasis. Insecticide application were largely applied to control the mosquito-mediated spread of these diseases, contributing to increasing rates of resistance in the mosquito population. The voltage-gated sodium channel (Vgsc) gene is the target site of pyrethroids, and mutations in this gene cause knockdown resistance (kdr). While these kdr mutations are known to be critical to pyrethroid resistance, their evolutionary origins remain poorly understood. Clarifying the origins of these mutations is potential to guide further vector control and disease prevention efforts. Accordingly, the present study was designed to study the evolutionary genetics of kdr mutations and their association with the population structure of Cx. p. pallens in Shandong province, China. METHODS Adult Culex females were collected from Shandong province and subjected to morphological identification under a dissection microscope. Genomic DNA were extracted from the collected mosquitoes, the Vgsc gene were amplified via PCR and sequenced to assess kdr allele frequencies, intron polymorphisms, and kdr codon evolution. In addition, population genetic diversity and related population characteristics were assessed by amplifying and sequencing the mitochondrial cytochrome C oxidase I (COI) gene. RESULTS Totally, 263 Cx. p. pallens specimens were used for DNA barcoding and sequencing analyses to assess kdr allele frequencies in nine Culex populations. The kdr codon L1014 in the Vgsc gene identified two non-synonymous mutations (L1014F and L1014S) in the analyzed population. These mutations were present in the eastern hilly area and west plain region of Shandong Province. However, only L1014F mutation was detected in the southern mountainous area and Dongying city of Shandong Province, where the mutation frequency was low. Compared to other cities, population in Qingdao revealed significant genetic differentiation. Spatial kdr mutation patterns are likely attributable to some combination of prolonged insecticide-mediated selection coupled with the genetic isolation of these mosquito populations. CONCLUSIONS These data suggest that multiple kdr alleles associated with insecticide resistance are present within the Cx. p. pallens populations of Shandong Province, China. The geographical distributions of kdr mutations in this province are likely that the result of prolonged and extensive insecticide application in agricultural contexts together with frequent mosquito population migrations. In contrast, the low-frequency kdr mutation detected in central Shandong Province populations may originate from the limited selection pressure in this area and the relative genetic isolation. Overall, the study compares the genetic patterns revealed by a functional gene with a neutral marker and demonstrates the combined impact of demographic and selection factors on population structure.
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Affiliation(s)
- Chuanhui Zang
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Xuejun Wang
- Shandong Center for Disease Control and Prevention, Jinan, Shandong, People's Republic of China
| | - Peng Cheng
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Lijuan Liu
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Xiuxia Guo
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Haifang Wang
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Ziwei Lou
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Jingjing Lei
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Wenqian Wang
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Yiting Wang
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China
| | - Maoqing Gong
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China.
| | - Hongmei Liu
- Department of Medical Entomology, Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, 272033, Shandong, People's Republic of China.
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11
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Anholt RRH, Mackay TFC. The genetic architecture of behavioral canalization. Trends Genet 2023:S0168-9525(23)00033-1. [PMID: 36878820 DOI: 10.1016/j.tig.2023.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 03/07/2023]
Abstract
Behaviors are components of fitness and contribute to adaptive evolution. Behaviors represent the interactions of an organism with its environment, yet innate behaviors display robustness in the face of environmental change, which we refer to as 'behavioral canalization'. We hypothesize that positive selection of hub genes of genetic networks stabilizes the genetic architecture for innate behaviors by reducing variation in the expression of interconnected network genes. Robustness of these stabilized networks would be protected from deleterious mutations by purifying selection or suppressing epistasis. We propose that, together with newly emerging favorable mutations, epistatically suppressed mutations can generate a reservoir of cryptic genetic variation that could give rise to decanalization when genetic backgrounds or environmental conditions change to allow behavioral adaptation.
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Affiliation(s)
- Robert R H Anholt
- Department of Genetics and Biochemistry and Center for Human Genetics, Clemson University, 114 Gregor Mendel Circle, Greenwood, SC 29646, USA.
| | - Trudy F C Mackay
- Department of Genetics and Biochemistry and Center for Human Genetics, Clemson University, 114 Gregor Mendel Circle, Greenwood, SC 29646, USA
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12
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Marion SB, Noor MAF. Interrogating the Roles of Mutation-Selection Balance, Heterozygote Advantage, and Linked Selection in Maintaining Recessive Lethal Variation in Natural Populations. Annu Rev Anim Biosci 2023; 11:77-91. [PMID: 36315650 DOI: 10.1146/annurev-animal-050422-092520] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
For nearly a century, evolutionary biologists have observed chromosomes that cause lethality when made homozygous persisting at surprisingly high frequencies (>25%) in natural populations of many species. The evolutionary forces responsible for the maintenance of such detrimental mutations have been heavily debated-are some lethal mutations under balancing selection? We suggest that mutation-selection balance alone cannot explain lethal variation in nature and the possibility that other forces play a role. We review the potential that linked selection in particular may drive maintenance of lethal alleles through associative overdominance or linkage to beneficial mutations or by reducing effective population size. Over the past five decades, investigation into this mystery has tapered. During this time, key scientific advances have provided the ability to collect more accurate data and analyze them in new ways, making the underlying genetic bases and evolutionary forces of lethal alleles timely for study once more.
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Affiliation(s)
- Sarah B Marion
- Department of Biology, Duke University, Durham, North Carolina, USA; ,
| | - Mohamed A F Noor
- Department of Biology, Duke University, Durham, North Carolina, USA; ,
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13
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Why does the X chromosome lag behind autosomes in GWAS findings? PLoS Genet 2023; 19:e1010472. [PMID: 36848382 PMCID: PMC9997976 DOI: 10.1371/journal.pgen.1010472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/09/2023] [Accepted: 02/15/2023] [Indexed: 03/01/2023] Open
Abstract
The X-chromosome is among the largest human chromosomes. It differs from autosomes by a number of important features including hemizygosity in males, an almost complete inactivation of one copy in females, and unique patterns of recombination. We used data from the Catalog of Published Genome Wide Association Studies to compare densities of the GWAS-detected SNPs on the X-chromosome and autosomes. The density of GWAS-detected SNPs on the X-chromosome is 6-fold lower compared to the density of the GWAS-detected SNPs on autosomes. Differences between the X-chromosome and autosomes cannot be explained by differences in the overall SNP density, lower X-chromosome coverage by genotyping platforms or low call rate of X-chromosomal SNPs. Similar differences in the density of GWAS-detected SNPs were found in female-only GWASs (e.g. ovarian cancer GWASs). We hypothesized that the lower density of GWAS-detected SNPs on the X-chromosome compared to autosomes is not a result of a methodological bias, e.g. differences in coverage or call rates, but has a real underlying biological reason-a lower density of functional SNPs on the X-chromosome versus autosomes. This hypothesis is supported by the observation that (i) the overall SNP density of X-chromosome is lower compared to the SNP density on autosomes and that (ii) the density of genic SNPs on the X-chromosome is lower compared to autosomes while densities of intergenic SNPs are similar.
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14
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Fiteni E, Durand K, Gimenez S, Meagher RL, Legeai F, Kergoat GJ, Nègre N, d’Alençon E, Nam K. Host-plant adaptation as a driver of incipient speciation in the fall armyworm (Spodoptera frugiperda). BMC Ecol Evol 2022; 22:133. [DOI: 10.1186/s12862-022-02090-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Divergent selection on host-plants is one of the main evolutionary forces driving ecological speciation in phytophagous insects. The ecological speciation might be challenging in the presence of gene flow and assortative mating because the direction of divergence is not necessarily the same between ecological selection (through host-plant adaptation) and assortative mating. The fall armyworm (FAW), a major lepidopteran pest species, is composed of two sympatric strains, corn and rice strains, named after two of their preferred host-plants. These two strains have been hypothesized to undergo incipient speciation, based on (i) several lines of evidence encompassing both pre- and post-zygotic reproductive isolation, and (ii) the presence of a substantial level of genetic differentiation. Even though the status of these two strains has been established a long time ago, it is still yet to be found whether these two strains indeed exhibit a marked level of genetic differentiation from a large number of genomic loci. Here, we analyzed whole genome sequences from 56 FAW individuals either collected from pasture grasses (a part of the favored host range of the rice strain) or corn to assess the role of host-plant adaptation in incipient speciation.
Results
Principal component analysis of whole genome data shows that the pattern of divergence in the fall armyworm is predominantly explained by the genetic differentiation associated with host-plants. The level of genetic differentiation between corn and rice strains is particularly marked in the Z chromosome. We identified one autosomal locus and two Z chromosome loci targeted by selective sweeps specific to rice strain and corn strain, respectively. The autosomal locus has both increased DXY and FST while the Z chromosome loci had decreased DXY and increased FST.
Conclusion
These results show that the FAW population structure is dominated by the genetic differentiation between corn and rice strains. This differentiation involves divergent selection targeting at least three loci, which include a locus potentially causing reproductive isolation. Taken together, these results suggest the evolutionary scenario that host-plant speciation is a driver of incipient speciation in the fall armyworm.
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15
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Gagnon CM, Svardal H, Jasinska AJ, Danzy Cramer J, Freimer NB, Paul Grobler J, Turner TR, Schmitt CA. Evidence of selection in the uncoupling protein 1 gene region suggests local adaptation to solar irradiance in savannah monkeys ( Chlorocebus spp.). Proc Biol Sci 2022; 289:20221254. [PMID: 36100027 PMCID: PMC9470266 DOI: 10.1098/rspb.2022.1254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/23/2022] [Indexed: 11/12/2022] Open
Abstract
In the last 300 thousand years, the genus Chlorocebus expanded from equatorial Africa into the southernmost latitudes of the continent, where colder climate was a probable driver of natural selection. We investigated population-level genetic variation in the mitochondrial uncoupling protein 1 (UCP1) gene region-implicated in non-shivering thermogenesis (NST)-in 73 wild savannah monkeys from three taxa representing this southern expansion (Chlorocebus pygerythrus hilgerti, Chlorocebus cynosuros and Chlorocebus pygerythrus pygerythrus) ranging from Kenya to South Africa. We found 17 single nucleotide polymorphisms with extended haplotype homozygosity consistent with positive selective sweeps, 10 of which show no significant linkage disequilibrium with each other. Phylogenetic generalized least-squares modelling with ecological covariates suggest that most derived allele frequencies are significantly associated with solar irradiance and winter precipitation, rather than overall low temperatures. This selection and association with irradiance is demonstrated by a relatively isolated population in the southern coastal belt of South Africa. We suggest that sunbathing behaviours common to savannah monkeys, in combination with the strength of solar irradiance, may mediate adaptations to thermal stress via NST among savannah monkeys. The variants we discovered all lie in non-coding regions, some with previously documented regulatory functions, calling for further validation and research.
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Affiliation(s)
| | - Hannes Svardal
- Department of Biology, University of Antwerp, Antwerp, Belgium
- Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Anna J. Jasinska
- Center for Neurobehavioral Genetics, University of California, Los Angeles, CA 90095, USA
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | - Nelson B. Freimer
- Center for Neurobehavioral Genetics, University of California, Los Angeles, CA 90095, USA
| | - J. Paul Grobler
- Department of Genetics, University of the Free State, Bloemfontein, Free State 9301, South Africa
| | - Trudy R. Turner
- Department of Genetics, University of the Free State, Bloemfontein, Free State 9301, South Africa
- Department of Anthropology, University of Wisconsin, Milwaukee, Milwaukee, WI, 53201, USA
| | - Christopher A. Schmitt
- Department of Anthropology, Boston University, Boston, MA 02215, USA
- Department of Biology, Boston University, Boston, MA 02215, USA
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16
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Akingbuwa WA, Hammerschlag AR, Bartels M, Nivard MG, Middeldorp CM. Ultra-rare and common genetic variant analysis converge to implicate negative selection and neuronal processes in the aetiology of schizophrenia. Mol Psychiatry 2022; 27:3699-3707. [PMID: 35665764 PMCID: PMC9708595 DOI: 10.1038/s41380-022-01621-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 04/21/2022] [Accepted: 05/11/2022] [Indexed: 02/08/2023]
Abstract
Both common and rare genetic variants (minor allele frequency >1% and <0.1% respectively) have been implicated in the aetiology of schizophrenia. In this study, we integrate single-cell gene expression data with publicly available Genome-Wide Association Study (GWAS) and exome sequenced data in order to investigate in parallel, the enrichment of common and (ultra-)rare variants related to schizophrenia in several functionally relevant gene-sets. Four types of gene-sets were constructed 1) protein-truncating variant (PTV)-intolerant (PI) genes 2) genes expressed in brain cell types and neurons ascertained from mouse and human brain tissue 3) genes defined by synaptic function and location and 4) intersection genes, i.e., PI genes that are expressed in the human and mouse brain cell gene-sets. We show that common as well as ultra-rare schizophrenia-associated variants are overrepresented in PI genes, in excitatory neurons from the prefrontal cortex and hippocampus, medium spiny neurons, and genes enriched for synaptic processes. We also observed stronger enrichment in the intersection genes. Our findings suggest that across the allele frequency spectrum, genes and genetic variants likely to be under stringent selection, and those expressed in particular brain cell types, are involved in the same biological pathways influencing the risk for schizophrenia.
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Affiliation(s)
- Wonuola A Akingbuwa
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
- Amsterdam Public Health Research Institute, Amsterdam University Medical Centres, Amsterdam, the Netherlands.
| | - Anke R Hammerschlag
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Amsterdam Public Health Research Institute, Amsterdam University Medical Centres, Amsterdam, the Netherlands
- Child Health Research Centre, the University of Queensland, Brisbane, QLD, Australia
| | - Meike Bartels
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Amsterdam Public Health Research Institute, Amsterdam University Medical Centres, Amsterdam, the Netherlands
| | - Michel G Nivard
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Christel M Middeldorp
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Child Health Research Centre, the University of Queensland, Brisbane, QLD, Australia
- Child and Youth Mental Health Service, Children's Health Queensland Hospital and Health Services, Brisbane, QLD, Australia
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17
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Crossley MS, Latimer CE, Kennedy CM, Snyder WE. Past and recent farming degrades aquatic insect genetic diversity. Mol Ecol 2022. [PMID: 35771845 DOI: 10.1111/mec.16590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 04/07/2022] [Accepted: 06/27/2022] [Indexed: 11/28/2022]
Abstract
Recent declines in once-common species are triggering concern that an environmental crisis point has been reached. Yet, the lack of long abundance time series data for most species can make it difficult to attribute these changes to anthropogenic causes, and to separate them from normal cycles. Genetic diversity, on the other hand, is sensitive to past and recent environmental changes, and reflects a measure of a populations' potential to adapt to future stressors. Here, we consider whether patterns of genetic diversity among aquatic insects can be linked to historical and recent patterns of land use change. We collated mitochondrial cytochrome c oxidase subunit I (COI) variation for >700 aquatic insect species across the United States, where patterns of agricultural expansion and intensification have been documented since the 1800s. We found that genetic diversity was lowest in regions where cropland was historically (pre-1950) most extensive, suggesting a legacy of past environmental harm. Genetic diversity further declined where cropland has since expanded, even after accounting for climate and sampling effects. Notably though, genetic diversity also appeared to rebound where cropland has diminished. Our study suggests that genetic diversity at the community level can be a powerful tool to infer potential population declines and rebounds over longer time spans than is typically possible with ecological data. For the aquatic insects that we considered, patterns of land use many decades ago appear to have left long-lasting damage to genetic diversity that could threaten evolutionary responses to rapid global change.
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Affiliation(s)
- Michael S Crossley
- Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE, USA
| | | | - Christina M Kennedy
- Global Protect Oceans, Lands and Waters Program, The Nature Conservancy, Fort Collins, CO, USA
| | - William E Snyder
- Department of Entomology, University of Georgia, Athens, GA, USA
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18
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Kumar H, Panigrahi M, Panwar A, Rajawat D, Nayak SS, Saravanan KA, Kaisa K, Parida S, Bhushan B, Dutt T. Machine-Learning Prospects for Detecting Selection Signatures Using Population Genomics Data. J Comput Biol 2022; 29:943-960. [PMID: 35639362 DOI: 10.1089/cmb.2021.0447] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Natural selection has been given a lot of attention because it relates to the adaptation of populations to their environments, both biotic and abiotic. An allele is selected when it is favored by natural selection. Consequently, the favored allele increases in frequency in the population and neighboring linked variation diminishes, causing so-called selective sweeps. A high-throughput genomic sequence allows one to disentangle the evolutionary forces at play in populations. With the development of high-throughput genome sequencing technologies, it has become easier to detect these selective sweeps/selection signatures. Various methods can be used to detect selective sweeps, from simple implementations using summary statistics to complex statistical approaches. One of the important problems of these statistical models is the potential to provide inaccurate results when their assumptions are violated. The use of machine learning (ML) in population genetics has been introduced as an alternative method of detecting selection by treating the problem of detecting selection signatures as a classification problem. Since the availability of population genomics data is increasing, researchers may incorporate ML into these statistical models to infer signatures of selection with higher predictive accuracy and better resolution. This article describes how ML can be used to aid in detecting and studying natural selection patterns using population genomic data.
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Affiliation(s)
- Harshit Kumar
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Manjit Panigrahi
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Anuradha Panwar
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Divya Rajawat
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Sonali Sonejita Nayak
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - K A Saravanan
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Kaiho Kaisa
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Subhashree Parida
- Divisions of Pharmacology and Toxicology, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Bharat Bhushan
- Divisions of Animal Genetics, ICAR-Indian Veterinary Research Institute, Izatnagar, India
| | - Triveni Dutt
- Livestock Production and Management Section, ICAR-Indian Veterinary Research Institute, Izatnagar, India
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19
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Ponnikas S, Sigeman H, Lundberg M, Hansson B. Extreme variation in recombination rate and genetic diversity along the Sylvioidea neo-sex chromosome. Mol Ecol 2022; 31:3566-3583. [PMID: 35578784 PMCID: PMC9327509 DOI: 10.1111/mec.16532] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/13/2022] [Accepted: 05/04/2022] [Indexed: 12/03/2022]
Abstract
Recombination strongly impacts sequence evolution by affecting the extent of linkage and the efficiency of selection. Here, we study recombination over the Z chromosome in great reed warblers (Acrocephalus arundinaceus) using pedigree‐based linkage mapping. This species has extended Z and W chromosomes (“neo‐sex chromosomes”) formed by a fusion between a part of chromosome 4A and the ancestral sex chromosomes, which provides a unique opportunity to assess recombination and sequence evolution in sex‐linked regions of different ages. We assembled an 87.54 Mbp and 90.19 cM large Z with a small pseudoautosomal region (0.89 Mbp) at one end and the fused Chr4A‐part at the other end of the chromosome. A prominent feature in our data was an extreme variation in male recombination rate along Z with high values at both chromosome ends, but an apparent lack of recombination over a substantial central section, covering 78% of the chromosome. The nonrecombining region showed a drastic loss of genetic diversity and accumulation of repeats compared to the recombining parts. Thus, our data emphasize a key role of recombination in affecting local levels of polymorphism. Nonetheless, the evolutionary rate of genes (dN/dS) did not differ between high and low recombining regions, suggesting that the efficiency of selection on protein‐coding sequences can be maintained also at very low levels of recombination. Finally, the Chr4A‐derived part showed a similar recombination rate as the part of the ancestral Z that did recombine, but its sequence characteristics reflected both its previous autosomal, and current Z‐linked, recombination patterns.
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Affiliation(s)
- Suvi Ponnikas
- Department of Biology, Lund University, Lund, Sweden.,Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Hanna Sigeman
- Department of Biology, Lund University, Lund, Sweden
| | - Max Lundberg
- Department of Biology, Lund University, Lund, Sweden
| | - Bengt Hansson
- Department of Biology, Lund University, Lund, Sweden
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20
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Selection signatures in melanocortin-1 receptor gene of turkeys (Meleagris gallopavo) raised in hot humid tropics. Trop Anim Health Prod 2022; 54:183. [PMID: 35525911 DOI: 10.1007/s11250-022-03185-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 04/28/2022] [Indexed: 10/18/2022]
Abstract
Feather colours are used by avian species for defense, adaptation and signaling. Melanocortin-1 receptor (MC1R) gene is one of the genes responsible for feather colour. This study identified selection signatures in MC1R gene of Nigerian indigenous turkeys (NIT) using British United turkeys (BUT) as control breed to investigate the evolutionary processes that have shaped NIT with various feather colours. Complete MC1R gene of 146 NIT (76 males and 70 females) and 32 BUT (18 males and 14 females) were sequenced. Transition/transversion and codon usage biases were predicted using MEGA v6 software. The selective force acting on the gene was predicted using HyPhy software. The FST values were estimated using Arlequin v3.5. The highest transition/transversion bias was predicted for white BUT (1.00) while the lowest was predicted for black NIT (0.50). Negative dN-dS values, indicative of purifying selection, were observed in MC1R gene of all the turkeys. The highest pairwise FST was observed between the MC1R gene of white BUT and black NIT while the least was observed between lavender NIT and white NIT. No recombination event was observed in black NIT and white BUT. The relative synonymous codon usage was the same among different colours for some codons. Presence of purifying selection in MC1R gene of all the turkeys with different feather colours confirms that the gene plays role in many biological processes such as feather colouration, behaviour, pain perception, immunity, growth and adaptation. The results also suggested that the genetic mechanisms generating different feather colours in turkeys are conserved.
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Wu J, Yonezawa T, Kishino H. Molecular Evolutionary Rate Predicts Intraspecific Genetic Polymorphism and Species-Specific Selection. Genes (Basel) 2022; 13:genes13040708. [PMID: 35456514 PMCID: PMC9031814 DOI: 10.3390/genes13040708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 12/04/2022] Open
Abstract
It is unknown what determines genetic diversity and how genetic diversity is associated with various biological traits. In this work, we provide insight into these issues. By comparing genetic variation of 14,671 mammalian gene trees with thousands of individual human, chimpanzee, gorilla, mouse, and dog/wolf genomes, we found that intraspecific genetic diversity can be predicted by long-term molecular evolutionary rates rather than de novo mutation rates. This relationship was established during the early stage of mammalian evolution. Moreover, we developed a method to detect fluctuations of species-specific selection on genes based on the deviations of intraspecific genetic diversity predicted from long-term rates. We showed that the evolution of epithelial cells, rather than connective tissue, mainly contributed to morphological evolution of different species. For humans, evolution of the immune system and selective sweeps caused by infectious diseases are the most representative examples of adaptive evolution.
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Affiliation(s)
- Jiaqi Wu
- Department of Molecular Life Science, Tokai University School of Medicine, Isehara 259-1193, Japan
- Correspondence: (J.W.); (H.K.)
| | - Takahiro Yonezawa
- Faculty of Agriculture, Tokyo University of Agriculture, Atsugi 243-0034, Japan;
| | - Hirohisa Kishino
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo Ward, Tokyo 113-8657, Japan
- The Research Institute of Evolutionary Biology, Tokyo 138-0098, Japan
- AI/Data Science Social Implementation Laboratory, Chuo University, Tokyo 112-8551, Japan
- Correspondence: (J.W.); (H.K.)
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22
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Li C, Liu K, Dai J, Li X, Liu X, Ni W, Li H, Wang D, Qiao J, Wang Y, Cui Y, Xia X, Hu S. Whole-genome resequencing to investigate the determinants of the multi-lumbar vertebrae trait in sheep. Gene 2022; 809:146020. [PMID: 34656743 DOI: 10.1016/j.gene.2021.146020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 10/03/2021] [Accepted: 10/11/2021] [Indexed: 12/25/2022]
Abstract
Multi-lumbar vertebrae trait is a beneficial mutation that can significantly improve livestock meat production. However, the genetic basis of the multi-lumbar vertebrae in sheep is still unclear. Here, we analysed the number of lumbar vertebrae of Duolang sheep and found three different traits of lumbar vertebrae number. Compared with the normal sheep, the length and weight of animal carcass from the multi-lumbar vertebrae sheep increased by 2.21 cm and 0.78 kg, respectively. We performed high-throughput genome resequencing on multi-lumbar vertebrae (n = 18) and normal (n = 11) Duolang sheep and obtained a total of more than 528.87 GB data. We found that the most significantly selective region were located in the 49.68-49.74 MB of chromosome 4 by selective-sweep analysis. We annotated this region and found that it contains SFRP4 which is known to regulate bone development. We further used the PCR-SSCP technology to detect the single nucleotide polymorphism (SNP) of the putative candidate SFRP4 and found that the two SNPs (rs600370085:C > T and rs415133338: A > G) of this gene were significantly associated with the multi-lumbar vertebrae of Duolang sheep. Our study indicates that the SFRP4 may be a potential major gene that affects the number of lumbar vertebrae in Duolang sheep, and has the potential to be utilized for sheep breeding in the future.
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Affiliation(s)
- Cunyuan Li
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China; College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Kaiping Liu
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Jihong Dai
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Xiaoyue Li
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Xia Liu
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Wei Ni
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Hui Li
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Dawei Wang
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Jun Qiao
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China.
| | - Yue Wang
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Yuying Cui
- College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China
| | - Xianzhu Xia
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China.
| | - Shengwei Hu
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang 832003, China; College of Life Science, Shihezi University, Shihezi, Xinjiang 832003, China.
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Lucena-Perez M, Kleinman-Ruiz D, Marmesat E, Saveljev AP, Schmidt K, Godoy JA. Bottleneck-associated changes in the genomic landscape of genetic diversity in wild lynx populations. Evol Appl 2021; 14:2664-2679. [PMID: 34815746 PMCID: PMC8591332 DOI: 10.1111/eva.13302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/17/2021] [Accepted: 09/08/2021] [Indexed: 01/06/2023] Open
Abstract
Demographic bottlenecks generally reduce genetic diversity through more intense genetic drift, but their net effect may vary along the genome due to the random nature of genetic drift and to local effects of recombination, mutation, and selection. Here, we analyzed the changes in genetic diversity following a bottleneck by comparing whole-genome diversity patterns in populations with and without severe recent documented declines of Iberian (Lynx pardinus, n = 31) and Eurasian lynx (Lynx lynx, n = 29). As expected, overall genomic diversity correlated negatively with bottleneck intensity and/or duration. Correlations of genetic diversity with divergence, chromosome size, gene or functional site content, GC content, or recombination were observed in nonbottlenecked populations, but were weaker in bottlenecked populations. Also, functional features under intense purifying selection and the X chromosome showed an increase in the observed density of variants, even resulting in higher θ W diversity than in nonbottlenecked populations. Increased diversity seems to be related to both a higher mutational input in those regions creating a large collection of low-frequency variants, a few of which increase in frequency during the bottleneck to the point they become detectable with our limited sample, and the reduced efficacy of purifying selection, which affects not only protein structure and function but also the regulation of gene expression. The results of this study alert to the possible reduction of fitness and adaptive potential associated with the genomic erosion in regulatory elements. Further, the detection of a gain of diversity in ultra-conserved elements can be used as a sensitive and easy-to-apply signature of genetic erosion in wild populations.
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Affiliation(s)
- Maria Lucena-Perez
- Departamento de Ecología Integrativa Estación Biológica de Doñana (CSIC) Sevilla Spain
| | - Daniel Kleinman-Ruiz
- Departamento de Ecología Integrativa Estación Biológica de Doñana (CSIC) Sevilla Spain
- Departamento de Genética Facultad de Biología Universidad Complutense Madrid Spain
| | - Elena Marmesat
- Departamento de Ecología Integrativa Estación Biológica de Doñana (CSIC) Sevilla Spain
| | - Alexander P Saveljev
- Department of Animal Ecology Russian Research Institute of Game Management and Fur Farming Kirov Russia
| | - Krzysztof Schmidt
- Mammal Research Institute Polish Academy of Sciences Białowieża Poland
| | - José A Godoy
- Departamento de Ecología Integrativa Estación Biológica de Doñana (CSIC) Sevilla Spain
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24
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Abstract
Drosophila melanogaster, a small dipteran of African origin, represents one of the best-studied model organisms. Early work in this system has uniquely shed light on the basic principles of genetics and resulted in a versatile collection of genetic tools that allow to uncover mechanistic links between genotype and phenotype. Moreover, given its worldwide distribution in diverse habitats and its moderate genome-size, Drosophila has proven very powerful for population genetics inference and was one of the first eukaryotes whose genome was fully sequenced. In this book chapter, we provide a brief historical overview of research in Drosophila and then focus on recent advances during the genomic era. After describing different types and sources of genomic data, we discuss mechanisms of neutral evolution including the demographic history of Drosophila and the effects of recombination and biased gene conversion. Then, we review recent advances in detecting genome-wide signals of selection, such as soft and hard selective sweeps. We further provide a brief introduction to background selection, selection of noncoding DNA and codon usage and focus on the role of structural variants, such as transposable elements and chromosomal inversions, during the adaptive process. Finally, we discuss how genomic data helps to dissect neutral and adaptive evolutionary mechanisms that shape genetic and phenotypic variation in natural populations along environmental gradients. In summary, this book chapter serves as a starting point to Drosophila population genomics and provides an introduction to the system and an overview to data sources, important population genetic concepts and recent advances in the field.
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Fumero MV, Yue W, Chiotta ML, Chulze SN, Leslie JF, Toomajian C. Divergence and Gene Flow Between Fusarium subglutinans and F. temperatum Isolated from Maize in Argentina. PHYTOPATHOLOGY 2021; 111:170-183. [PMID: 33079019 DOI: 10.1094/phyto-09-20-0434-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Fusarium subglutinans and F. temperatum are two important fungal pathogens of maize whose distinctness as separate species has been difficult to assess. We isolated strains of these species from commercial and native maize varieties in Argentina and sequenced >28,000 loci to estimate genetic variation in the sample. Our objectives were to measure genetic divergence between the species, infer demographic parameters related to their split, and describe the population structure of the sample. When analyzed together, over 30% of each species' polymorphic sites (>2,500 sites) segregate as polymorphisms in the other. Demographic modeling confirmed the species split predated maize domestication, but subsequent between-species gene flow has occurred, with gene flow from F. subglutinans into F. temperatum greater than gene flow in the reverse direction. In F. subglutinans, little evidence exists for substructure or recent selective sweeps, but there is evidence for limited sexual reproduction. In F. temperatum, there is clear evidence for population substructure and signals of abundant recent selective sweeps, with sexual reproduction probably less common than in F. subglutinans. Both genetic variation and the relative number of polymorphisms shared between species increase near the telomeres of all 12 chromosomes, where genes related to plant-pathogen interactions often are located. Our results suggest that species boundaries between closely related Fusarium species can be semipermeable and merit further study. Such semipermeability could facilitate unanticipated genetic exchange between species and enable quicker permanent responses to changes in the agro-ecosystem, e.g., pathogen-resistant host varieties, new chemical and biological control agents, and agronomic practices.
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Affiliation(s)
- M Veronica Fumero
- Research Institute on Mycology and Mycotoxicology (IMICO), National Scientific and Technical Research Council-National University of Río Cuarto (CONICET-UNRC), X5800, Río Cuarto, Córdoba, Argentina
| | - Wei Yue
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, U.S.A
| | - María L Chiotta
- Research Institute on Mycology and Mycotoxicology (IMICO), National Scientific and Technical Research Council-National University of Río Cuarto (CONICET-UNRC), X5800, Río Cuarto, Córdoba, Argentina
| | - Sofía N Chulze
- Research Institute on Mycology and Mycotoxicology (IMICO), National Scientific and Technical Research Council-National University of Río Cuarto (CONICET-UNRC), X5800, Río Cuarto, Córdoba, Argentina
| | - John F Leslie
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, U.S.A
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Rendueles O, Velicer GJ. Hidden paths to endless forms most wonderful: Complexity of bacterial motility shapes diversification of latent phenotypes. BMC Evol Biol 2020; 20:145. [PMID: 33148179 PMCID: PMC7641858 DOI: 10.1186/s12862-020-01707-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/20/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Evolution in one selective environment often latently generates phenotypic change that is manifested only later in different environments, but the complexity of behavior important to fitness in the original environment might influence the character of such latent-phenotype evolution. Using Myxococcus xanthus, a bacterium possessing two motility systems differing in effectiveness on hard vs. soft surfaces, we test (i) whether and how evolution while swarming on one surface-the selective surface-latently alters motility on the alternative surface type and (ii) whether patterns of such latent-phenotype evolution depend on the complexity of ancestral motility, specific ancestral motility genotypes and/or the selective surface of evolution. We analysze an experiment in which populations established from three ancestral genotypes-one with both motility systems intact and two others with one system debilitated-evolved while swarming across either hard or soft agar in six evolutionary treatments. We then compare motility-phenotype patterns across selective vs. alternative surface types. RESULTS Latent motility evolution was pervasive but varied in character as a function of the presence of one or two functional motility systems and, for some individual-treatment comparisons, the specific ancestral genotype and/or selective surface. Swarming rates on alternative vs. selective surfaces were positively correlated generally among populations with one functional motility system but not among those with two. This suggests that opportunities for pleiotropy and epistasis generated by increased genetic complexity underlying behavior can alter the character of latent-phenotype evolution. No tradeoff between motility performance across surface types was detected in the dual-system treatments, even after adaptation on a surface on which one motility system dominates strongly over the other in driving movement, but latent-phenotype evolution was instead idiosyncratic in these treatments. We further find that the magnitude of stochastic diversification at alternative-surface swarming among replicate populations greatly exceeded diversification of selective-surface swarming within some treatments and varied across treatments. CONCLUSION Collectively, our results suggest that increases in the genetic and mechanistic complexity of behavior can increase the complexity of latent-phenotype evolution outcomes and illustrate that diversification manifested during evolution in one environment can be augmented greatly by diversification of latent phenotypes manifested later.
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Affiliation(s)
- Olaya Rendueles
- Institute for Integrative Biology, ETH Zurich, Universitätstrasse 16, 8092, Zurich, Switzerland. .,Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, 75015, Paris, France.
| | - Gregory J Velicer
- Institute for Integrative Biology, ETH Zurich, Universitätstrasse 16, 8092, Zurich, Switzerland
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27
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Ababaikeri B, Abduriyim S, Tohetahong Y, Mamat T, Ahmat A, Halik M. Whole-genome sequencing of Tarim red deer ( Cervus elaphus yarkandensis) reveals demographic history and adaptations to an arid-desert environment. Front Zool 2020; 17:31. [PMID: 33072165 PMCID: PMC7565370 DOI: 10.1186/s12983-020-00379-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/02/2020] [Indexed: 01/08/2023] Open
Abstract
Background The initiation of desert conditions in the Tarim Basin in China since the late Miocene has led to the significant genetic structuring of local organisms. Tarim Red Deer (Cervus elaphus yarkandensis, TRD) have adapted to the harsh environmental conditions in this basin, including high solar radiation and temperature, aridity, and poor nutritional conditions. However, the underlying genetic basis of this adaptation is poorly understood. Results We sequenced the whole genomes of 13 TRD individuals, conducted comparative genomic analyses, and estimated demographic fluctuation. The ∂a∂i model estimated that the TRD and Tule elk (Cervus canadensis nannodes) populations diverged approximately 0.98 Mya. Analyses revealed a substantial influence of the Earth’s climate on the effective population size of TRD, associated with glacial advances and retreat, and human activities likely underlie a recent serious decline in population. A marked bottleneck may have profoundly affected the genetic diversity of TRD populations. We detected a set of candidate genes, pathways, and GO categories related to oxidative stress, water reabsorption, immune regulation, energy metabolism, eye protection, heat stress, respiratory system adaptation, prevention of high blood pressure, and DNA damage and repair that may directly or indirectly be involved in the adaptation of TRD to an arid-desert environment. Conclusions Our analyses highlight the role of historical global climates in the population dynamics of TRD. In light of ongoing global warming and the increasing incidence of droughts, our study offers insights into the genomic adaptations of animals, especially TRD, to extreme arid-desert environments and provides a valuable resource for future research on conservation design and biological adaptations to environmental change.
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Affiliation(s)
- Buweihailiqiemu Ababaikeri
- College of Life Sciences and Technology, Xinjiang University, Urumqi, 830046 Xinjiang China.,College of Xinjiang Uyghur Medicine, Hoten, 848000 Xinjiang China
| | - Shamshidin Abduriyim
- College of Life Science, Shihezi University, Shihezi, 832003 Xinjiang China.,Department of Ecology, Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, 430072 Hubei China
| | - Yilamujiang Tohetahong
- College of Life Sciences and Technology, Xinjiang University, Urumqi, 830046 Xinjiang China
| | - Tayerjan Mamat
- College of Life Sciences and Technology, Xinjiang University, Urumqi, 830046 Xinjiang China
| | - Adil Ahmat
- College of Life Sciences and Technology, Xinjiang University, Urumqi, 830046 Xinjiang China
| | - Mahmut Halik
- College of Life Sciences and Technology, Xinjiang University, Urumqi, 830046 Xinjiang China
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28
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Schrider DR. Background Selection Does Not Mimic the Patterns of Genetic Diversity Produced by Selective Sweeps. Genetics 2020; 216:499-519. [PMID: 32847814 PMCID: PMC7536861 DOI: 10.1534/genetics.120.303469] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 08/04/2020] [Indexed: 12/28/2022] Open
Abstract
It is increasingly evident that natural selection plays a prominent role in shaping patterns of diversity across the genome. The most commonly studied modes of natural selection are positive selection and negative selection, which refer to directional selection for and against derived mutations, respectively. Positive selection can result in hitchhiking events, in which a beneficial allele rapidly replaces all others in the population, creating a valley of diversity around the selected site along with characteristic skews in allele frequencies and linkage disequilibrium among linked neutral polymorphisms. Similarly, negative selection reduces variation not only at selected sites but also at linked sites, a phenomenon called background selection (BGS). Thus, discriminating between these two forces may be difficult, and one might expect efforts to detect hitchhiking to produce an excess of false positives in regions affected by BGS. Here, we examine the similarity between BGS and hitchhiking models via simulation. First, we show that BGS may somewhat resemble hitchhiking in simplistic scenarios in which a region constrained by negative selection is flanked by large stretches of unconstrained sites, echoing previous results. However, this scenario does not mirror the actual spatial arrangement of selected sites across the genome. By performing forward simulations under more realistic scenarios of BGS, modeling the locations of protein-coding and conserved noncoding DNA in real genomes, we show that the spatial patterns of variation produced by BGS rarely mimic those of hitchhiking events. Indeed, BGS is not substantially more likely than neutrality to produce false signatures of hitchhiking. This holds for simulations modeled after both humans and Drosophila, and for several different demographic histories. These results demonstrate that appropriately designed scans for hitchhiking need not consider BGS's impact on false-positive rates. However, we do find evidence that BGS increases the false-negative rate for hitchhiking, an observation that demands further investigation.
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Affiliation(s)
- Daniel R Schrider
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27514
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Genome-Wide Association Study Reveals Novel Candidate Genes Associated with Productivity and Disease Resistance to Moniliophthora spp. in Cacao ( Theobroma cacao L.). G3-GENES GENOMES GENETICS 2020; 10:1713-1725. [PMID: 32169867 PMCID: PMC7202020 DOI: 10.1534/g3.120.401153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cacao (Theobroma cacao L.), the source of chocolate, is one of the most important commodity products worldwide that helps improve the economic livelihood of farmers. Diseases like frosty pod rot caused by Moniliophthora roreri and witches’ broom caused by Moniliophthora perniciosa limit the cacao productivity, this can be solved by using resistant varieties. In the current study, we sequenced 229 cacao accessions using genotyping-by-sequencing to examine the genetic diversity and population structure employing 9,003 and 8,131 single nucleotide polymorphisms recovered by mapping against two cacao genomes (Criollo B97-61/B2 v2 and Matina 1-6 v1.1). In the phenotypic evaluation, three promising accessions for productivity and 10 with good tolerance to the frosty pod rot and witches’ broom diseases were found. A genome-wide association study was performed on 102 accessions, discovering two genes associated with productivity and seven to disease resistance. The results enriched the knowledge of the genetic regions associated with important cacao traits that can have significant implications for conservation and breeding strategies like marker-assisted selection.
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30
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Johri P, Charlesworth B, Jensen JD. Toward an Evolutionarily Appropriate Null Model: Jointly Inferring Demography and Purifying Selection. Genetics 2020; 215:173-192. [PMID: 32152045 PMCID: PMC7198275 DOI: 10.1534/genetics.119.303002] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/05/2020] [Indexed: 01/27/2023] Open
Abstract
The question of the relative evolutionary roles of adaptive and nonadaptive processes has been a central debate in population genetics for nearly a century. While advances have been made in the theoretical development of the underlying models, and statistical methods for estimating their parameters from large-scale genomic data, a framework for an appropriate null model remains elusive. A model incorporating evolutionary processes known to be in constant operation, genetic drift (as modulated by the demographic history of the population) and purifying selection, is lacking. Without such a null model, the role of adaptive processes in shaping within- and between-population variation may not be accurately assessed. Here, we investigate how population size changes and the strength of purifying selection affect patterns of variation at "neutral" sites near functional genomic components. We propose a novel statistical framework for jointly inferring the contribution of the relevant selective and demographic parameters. By means of extensive performance analyses, we quantify the utility of the approach, identify the most important statistics for parameter estimation, and compare the results with existing methods. Finally, we reanalyze genome-wide population-level data from a Zambian population of Drosophila melanogaster, and find that it has experienced a much slower rate of population growth than was inferred when the effects of purifying selection were neglected. Our approach represents an appropriate null model, against which the effects of positive selection can be assessed.
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Affiliation(s)
- Parul Johri
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287
| | - Brian Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - Jeffrey D Jensen
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287
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31
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Feng C, Yi H, Yang L, Kang M. The genetic basis of hybrid male sterility in sympatric Primulina species. BMC Evol Biol 2020; 20:49. [PMID: 32349663 PMCID: PMC7191819 DOI: 10.1186/s12862-020-01617-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 04/21/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Sympatric sister species provide an opportunity to investigate the genetic mechanisms and evolutionary forces that maintain species boundaries. The persistence of morphologically and genetically distinct populations in sympatry can only occur if some degree of reproductive isolation exists. A pair of sympatric sister species of Primulina (P. depressa and P. danxiaensis) was used to explore the genetic architecture of hybrid male sterility. RESULTS We mapped one major- and seven minor-effect quantitative trait loci (QTLs) that underlie pollen fertility rate (PFR). These loci jointly explained 55.4% of the phenotypic variation in the F2 population. A Bateson-Dobzhansky-Muller (BDM) model involving three loci was observed in this system. We found genotypic correlations between hybrid male sterility and flower morphology, consistent with the weak but significant phenotypic correlations between PFR and floral traits. CONCLUSIONS Hybrid male sterility in Primulina is controlled by a polygenic genetic basis with a complex pattern. The genetic incompatibility involves a three-locus BDM model. Hybrid male sterility is genetically correlated with floral morphology and divergence hitchhiking may occur between them.
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Affiliation(s)
- Chen Feng
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650 China
| | - Huiqin Yi
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Lihua Yang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650 China
| | - Ming Kang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650 China
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32
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Koropoulis A, Alachiotis N, Pavlidis P. Detecting Positive Selection in Populations Using Genetic Data. Methods Mol Biol 2020; 2090:87-123. [PMID: 31975165 DOI: 10.1007/978-1-0716-0199-0_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
High-throughput genomic sequencing allows to disentangle the evolutionary forces acting in populations. Among evolutionary forces, positive selection has received a lot of attention because it is related to the adaptation of populations in their environments, both biotic and abiotic. Positive selection, also known as Darwinian selection, occurs when an allele is favored by natural selection. The frequency of the favored allele increases in the population and, due to genetic hitchhiking, neighboring linked variation diminishes, creating so-called selective sweeps. Such a process leaves traces in genomes that can be detected in a future time point. Detecting traces of positive selection in genomes is achieved by searching for signatures introduced by selective sweeps, such as regions of reduced variation, a specific shift of the site frequency spectrum, and particular linkage disequilibrium (LD) patterns in the region. A variety of approaches can be used for detecting selective sweeps, ranging from simple implementations that compute summary statistics to more advanced statistical approaches, e.g., Bayesian approaches, maximum-likelihood-based methods, and machine learning methods. In this chapter, we discuss selective sweep detection methodologies on the basis of their capacity to analyze whole genomes or just subgenomic regions, and on the specific polymorphism patterns they exploit as selective sweep signatures. We also summarize the results of comparisons among five open-source software releases (SweeD, SweepFinder, SweepFinder2, OmegaPlus, and RAiSD) regarding sensitivity, specificity, and execution times. Furthermore, we test and discuss machine learning methods and present a thorough performance analysis. In equilibrium neutral models or mild bottlenecks, most methods are able to detect selective sweeps accurately. Methods and tools that rely on linkage disequilibrium (LD) rather than single SNPs exhibit higher true positive rates than the site frequency spectrum (SFS)-based methods under the model of a single sweep or recurrent hitchhiking. However, their false positive rate is elevated when a misspecified demographic model is used to build the distribution of the statistic under the null hypothesis. Both LD and SFS-based approaches suffer from decreased accuracy on localizing the true target of selection in bottleneck scenarios. Furthermore, we present an extensive analysis of the effects of gene flow on selective sweep detection, a problem that has been understudied in selective sweep literature.
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Affiliation(s)
- Angelos Koropoulis
- Institute of Computer Science, Foundation for Research and Technology Hellas, Heraklion, Greece
- Computer Science Department, University of Crete, Crete, Heraklion, Greece
| | - Nikolaos Alachiotis
- Institute of Computer Science, Foundation for Research and Technology Hellas, Heraklion, Greece
| | - Pavlos Pavlidis
- Institute of Computer Science, Foundation for Research and Technology Hellas, Heraklion, Greece.
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33
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Matthey‐Doret R, Whitlock MC. Background selection andFST: Consequences for detecting local adaptation. Mol Ecol 2019; 28:3902-3914. [DOI: 10.1111/mec.15197] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 06/19/2019] [Accepted: 07/03/2019] [Indexed: 01/03/2023]
Affiliation(s)
- Remi Matthey‐Doret
- Department of Zoology and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
| | - Michael C. Whitlock
- Department of Zoology and Biodiversity Research Centre University of British Columbia Vancouver BC Canada
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34
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Cutter AD, Morran LT, Phillips PC. Males, Outcrossing, and Sexual Selection in Caenorhabditis Nematodes. Genetics 2019; 213:27-57. [PMID: 31488593 PMCID: PMC6727802 DOI: 10.1534/genetics.119.300244] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022] Open
Abstract
Males of Caenorhabditis elegans provide a crucial practical tool in the laboratory, but, as the rarer and more finicky sex, have not enjoyed the same depth of research attention as hermaphrodites. Males, however, have attracted the attention of evolutionary biologists who are exploiting the C. elegans system to test longstanding hypotheses about sexual selection, sexual conflict, transitions in reproductive mode, and genome evolution, as well as to make new discoveries about Caenorhabditis organismal biology. Here, we review the evolutionary concepts and data informed by study of males of C. elegans and other Caenorhabditis We give special attention to the important role of sperm cells as a mediator of inter-male competition and male-female conflict that has led to drastic trait divergence across species, despite exceptional phenotypic conservation in many other morphological features. We discuss the evolutionary forces important in the origins of reproductive mode transitions from males being common (gonochorism: females and males) to rare (androdioecy: hermaphrodites and males) and the factors that modulate male frequency in extant androdioecious populations, including the potential influence of selective interference, host-pathogen coevolution, and mutation accumulation. Further, we summarize the consequences of males being common vs rare for adaptation and for trait divergence, trait degradation, and trait dimorphism between the sexes, as well as for molecular evolution of the genome, at both micro-evolutionary and macro-evolutionary timescales. We conclude that C. elegans male biology remains underexploited and that future studies leveraging its extensive experimental resources are poised to discover novel biology and to inform profound questions about animal function and evolution.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario M5S3B2, Canada
| | - Levi T Morran
- Department of Biology, Emory University, Atlanta, Georgia 30322, and
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403
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35
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Li C, Li M, Li X, Ni W, Xu Y, Yao R, Wei B, Zhang M, Li H, Zhao Y, Liu L, Ullah Y, Jiang Y, Hu S. Whole-Genome Resequencing Reveals Loci Associated With Thoracic Vertebrae Number in Sheep. Front Genet 2019; 10:674. [PMID: 31379930 PMCID: PMC6657399 DOI: 10.3389/fgene.2019.00674] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/27/2019] [Indexed: 12/31/2022] Open
Abstract
The number of vertebrae, especially thoracic vertebrae, is an important economic trait that may influence carcass length and meat production in animals. However, the genetic basis of vertebrae number in sheep is still poorly understood. To detect the candidate genes, 400 increased number of thoracic vertebrae (T14L6) and 200 normal (T13L6) Kazakh sheep were collected. We generated and sequenced 60 pools of genomic DNA (each pool prepared by mixing genomic DNA from 10 sheep with the same thoracic traits), with an average depth of coverage of 25.65×. We identified a total of 42,075,402 SNPs and 11 putatively selected genomic regions, including the VRTN gene and the HoxA gene family that regulate vertebral development. The most prominent areas of selective elimination were located in a region of chromosome 7, including VRTN, which regulates spinal development and morphology. Further investigation indicated that the expression level of the VRTN gene during fetal development was significantly higher in sheep with more thoracic vertebrae than in those with a normal number of thoracic vertebrae. A genome-wide comparison between sheep with increased and normal numbers of thoracic vertebrae showed that the VRTN gene is the major selection locus for the number of thoracic vertebrae in sheep and has the potential to be utilized in sheep breeding in the future.
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Affiliation(s)
- Cunyuan Li
- College of Life Sciences, Shihezi University, Shihezi, China.,College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Ming Li
- College of Animal Science and Technology, Northwest A&F University, Xianyang, China
| | - Xiaoyue Li
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Wei Ni
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Yueren Xu
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Rui Yao
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Bin Wei
- College of Animal Science and Technology, Northwest A&F University, Xianyang, China
| | - Mengdan Zhang
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Huixiang Li
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Yue Zhao
- College of Animal Science and Technology, Northwest A&F University, Xianyang, China
| | - Li Liu
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Yaseen Ullah
- College of Life Sciences, Shihezi University, Shihezi, China
| | - Yu Jiang
- College of Animal Science and Technology, Northwest A&F University, Xianyang, China
| | - Shengwei Hu
- College of Life Sciences, Shihezi University, Shihezi, China
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36
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Booker TR, Keightley PD. Understanding the Factors That Shape Patterns of Nucleotide Diversity in the House Mouse Genome. Mol Biol Evol 2019; 35:2971-2988. [PMID: 30295866 PMCID: PMC6278861 DOI: 10.1093/molbev/msy188] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A major goal of population genetics has been to determine the extent by which selection at linked sites influences patterns of neutral nucleotide diversity in the genome. Multiple lines of evidence suggest that diversity is influenced by both positive and negative selection. For example, in many species there are troughs in diversity surrounding functional genomic elements, consistent with the action of either background selection (BGS) or selective sweeps. In this study, we investigated the causes of the diversity troughs that are observed in the wild house mouse genome. Using the unfolded site frequency spectrum, we estimated the strength and frequencies of deleterious and advantageous mutations occurring in different functional elements in the genome. We then used these estimates to parameterize forward-in-time simulations of chromosomes, using realistic distributions of functional elements and recombination rate variation in order to determine whether selection at linked sites can explain the observed patterns of nucleotide diversity. The simulations suggest that BGS alone cannot explain the dips in diversity around either exons or conserved noncoding elements. A combination of BGS and selective sweeps produces deeper dips in diversity than BGS alone, but the inferred parameters of selection cannot fully explain the patterns observed in the genome. Our results provide evidence of sweeps shaping patterns of nucleotide diversity across the mouse genome and also suggest that infrequent, strongly advantageous mutations play an important role in this. The limitations of using the unfolded site frequency spectrum for inferring the frequency and effects of advantageous mutations are discussed.
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Affiliation(s)
- Tom R Booker
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom.,Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Peter D Keightley
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
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37
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Larson WA, Dann TH, Limborg MT, McKinney GJ, Seeb JE, Seeb LW. Parallel signatures of selection at genomic islands of divergence and the major histocompatibility complex in ecotypes of sockeye salmon across Alaska. Mol Ecol 2019; 28:2254-2271. [DOI: 10.1111/mec.15082] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 02/21/2019] [Accepted: 03/20/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Wesley A. Larson
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
| | - Tyler H. Dann
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
- Gene Conservation Laboratory Alaska Department of Fish and Game Anchorage Alaska
| | - Morten T. Limborg
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
| | - Garrett J. McKinney
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
| | - James E. Seeb
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
| | - Lisa W. Seeb
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
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38
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The Effects on Neutral Variability of Recurrent Selective Sweeps and Background Selection. Genetics 2019; 212:287-303. [PMID: 30923166 DOI: 10.1534/genetics.119.301951] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/19/2019] [Indexed: 12/11/2022] Open
Abstract
Levels of variability and rates of adaptive evolution may be affected by hitchhiking, the effect of selection on evolution at linked sites. Hitchhiking can be caused either by "selective sweeps" or by background selection, involving the spread of new favorable alleles or the elimination of deleterious mutations, respectively. Recent analyses of population genomic data have fitted models where both these processes act simultaneously, to infer the parameters of selection. Here, we investigate the consequences of relaxing a key assumption of some of these studies, that the time occupied by a selective sweep is negligible compared with the neutral coalescent time. We derive a new expression for the expected level of neutral variability in the presence of recurrent selective sweeps and background selection. We also derive approximate integral expressions for the effects of recurrent selective sweeps. The accuracy of the theoretical predictions was tested against multilocus simulations, with selection, recombination, and mutation parameters that are realistic for Drosophila melanogaster In the presence of crossing over, there is approximate agreement between the theoretical and simulation results. We show that the observed relationships between the rate of crossing over, and the level of synonymous site diversity and rate of adaptive evolution in Drosophila are probably mainly caused by background selection, whereas selective sweeps and population size changes are needed to produce the observed distortions of the site frequency spectrum.
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39
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Low genetic variation is associated with low mutation rate in the giant duckweed. Nat Commun 2019; 10:1243. [PMID: 30886148 PMCID: PMC6423293 DOI: 10.1038/s41467-019-09235-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 02/27/2019] [Indexed: 12/30/2022] Open
Abstract
Mutation rate and effective population size (Ne) jointly determine intraspecific genetic diversity, but the role of mutation rate is often ignored. Here we investigate genetic diversity, spontaneous mutation rate and Ne in the giant duckweed (Spirodela polyrhiza). Despite its large census population size, whole-genome sequencing of 68 globally sampled individuals reveals extremely low intraspecific genetic diversity. Assessed under natural conditions, the genome-wide spontaneous mutation rate is at least seven times lower than estimates made for other multicellular eukaryotes, whereas Ne is large. These results demonstrate that low genetic diversity can be associated with large-Ne species, where selection can reduce mutation rates to very low levels. This study also highlights that accurate estimates of mutation rate can help to explain seemingly unexpected patterns of genome-wide variation. While the role of effective population size (Ne) in explaining variation in genetic diversity has received much attention, the role of spontaneous mutation rate is largely ignored. Here, Xu et al. show that giant duckweed has a high Ne yet low genetic diversity, likely due to its low mutation rate.
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40
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How Linked Selection Shapes the Diversity Landscape in Ficedula Flycatchers. Genetics 2019; 212:277-285. [PMID: 30872320 PMCID: PMC6499528 DOI: 10.1534/genetics.119.301991] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/07/2019] [Indexed: 12/19/2022] Open
Abstract
There is an increasing awareness that selection affecting linked neutral sites strongly influences on how diversity is distributed across the genome. In particular, linked selection is likely involved in the formation of heterogenous landscapes of genetic diversity, including genomic regions with locally reduced effective population sizes that manifest as dips in diversity, and "islands" of differentiation between closely related populations or species. Linked selection can be in the form of background selection or selective sweeps, and a long-standing quest in population genetics has been to unveil the relative importance of these processes. Here, we analyzed the theoretically expected reduction of diversity caused by linked selection in the collared flycatcher (Ficedula albicollis) genome and compared this with population genomic data on the distribution of diversity across the flycatcher genome. By incorporating data on recombination rate variation and the density of target sites for selection (including both protein-coding genes and conserved noncoding elements), we found that background selection can explain most of the observed baseline variation in genetic diversity. However, positive selection was necessary to explain the pronounced local diversity dips in the collared flycatcher genome. We confirmed our analytical findings by comprehensive simulations. Therefore, our study demonstrates that even though both background selection and selective sweeps contribute to the heterogeneous diversity landscape seen in this avian system, they play different roles in shaping it.
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41
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Abstract
For almost 20 years, many inference methods have been developed to detect selective sweeps and localize the targets of directional selection in the genome. These methods are based on population genetic models that describe the effect of a beneficial allele (e.g., a new mutation) on linked neutral variation (driven by directional selection from a single copy to fixation). Here, I discuss these models, ranging from selective sweeps in a panmictic population of constant size to evolutionary traffic when simultaneous sweeps at multiple loci interfere, and emphasize the important role of demography and population structure in data analysis. In the past 10 years, soft sweeps that may arise after an environmental change from directional selection on standing variation have become a focus of population genetic research. In contrast to selective sweeps, they are caused by beneficial alleles that were neutrally segregating in a population before the environmental change or were present at a mutation-selection balance in appreciable frequency.
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42
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Jensen JD, Payseur BA, Stephan W, Aquadro CF, Lynch M, Charlesworth D, Charlesworth B. The importance of the Neutral Theory in 1968 and 50 years on: A response to Kern and Hahn 2018. Evolution 2019; 73:111-114. [PMID: 30460993 PMCID: PMC6496948 DOI: 10.1111/evo.13650] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 11/09/2018] [Indexed: 01/31/2023]
Abstract
A recent article reassessing the Neutral Theory of Molecular Evolution claims that it is no longer as important as is widely believed. The authors argue that "the neutral theory was supported by unreliable theoretical and empirical evidence from the beginning, and that in light of modern, genome-scale data, we can firmly reject its universality." Claiming that "the neutral theory has been overwhelmingly rejected," they propose instead that natural selection is the major force shaping both between-species divergence and within-species variation. Although this is probably a minority view, it is important to evaluate such claims carefully in the context of current knowledge, as inaccuracies can sometimes morph into an accepted narrative for those not familiar with the underlying science. We here critically examine and ultimately reject Kern and Hahn's arguments and assessment, and instead propose that it is now abundantly clear that the foundational ideas presented five decades ago by Kimura and Ohta are indeed correct.
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Affiliation(s)
| | - Bret A. Payseur
- Laboratory of Genetics, University of Wisconsin-Madison,
Madison, Wisconsin
| | - Wolfgang Stephan
- Leibniz-Institute for Evolution and Biodiversity Science,
Berlin, Germany
| | - Charles F. Aquadro
- Department of Molecular Biology & Genetics, Cornell
University, Ithaca, New York
| | - Michael Lynch
- Center for Mechanisms of Evolution, Arizona State
University, Tempe, Arizona
| | - Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological
Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Brian Charlesworth
- Institute of Evolutionary Biology, School of Biological
Sciences, University of Edinburgh, Edinburgh, United Kingdom
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43
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Pouyet F, Aeschbacher S, Thiéry A, Excoffier L. Background selection and biased gene conversion affect more than 95% of the human genome and bias demographic inferences. eLife 2018; 7:e36317. [PMID: 30125248 PMCID: PMC6177262 DOI: 10.7554/elife.36317] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 08/17/2018] [Indexed: 12/15/2022] Open
Abstract
Disentangling the effect on genomic diversity of natural selection from that of demography is notoriously difficult, but necessary to properly reconstruct the history of species. Here, we use high-quality human genomic data to show that purifying selection at linked sites (i.e. background selection, BGS) and GC-biased gene conversion (gBGC) together affect as much as 95% of the variants of our genome. We find that the magnitude and relative importance of BGS and gBGC are largely determined by variation in recombination rate and base composition. Importantly, synonymous sites and non-transcribed regions are also affected, albeit to different degrees. Their use for demographic inference can lead to strong biases. However, by conditioning on genomic regions with recombination rates above 1.5 cM/Mb and mutation types (C↔G, A↔T), we identify a set of SNPs that is mostly unaffected by BGS or gBGC, and that avoids these biases in the reconstruction of human history.
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Affiliation(s)
- Fanny Pouyet
- Computational and Molecular Population Genetics, Institute of Ecology and EvolutionUniversity of BernBernSwitzerland
- Swiss Institute of BioinformaticsLausanneSwitzerland
| | - Simon Aeschbacher
- Computational and Molecular Population Genetics, Institute of Ecology and EvolutionUniversity of BernBernSwitzerland
- Swiss Institute of BioinformaticsLausanneSwitzerland
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| | - Alexandre Thiéry
- Computational and Molecular Population Genetics, Institute of Ecology and EvolutionUniversity of BernBernSwitzerland
- Swiss Institute of BioinformaticsLausanneSwitzerland
| | - Laurent Excoffier
- Computational and Molecular Population Genetics, Institute of Ecology and EvolutionUniversity of BernBernSwitzerland
- Swiss Institute of BioinformaticsLausanneSwitzerland
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44
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Alachiotis N, Pavlidis P. RAiSD detects positive selection based on multiple signatures of a selective sweep and SNP vectors. Commun Biol 2018; 1:79. [PMID: 30271960 PMCID: PMC6123745 DOI: 10.1038/s42003-018-0085-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 06/05/2018] [Indexed: 12/16/2022] Open
Abstract
Selective sweeps leave distinct signatures locally in genomes, enabling the detection of loci that have undergone recent positive selection. Multiple signatures of a selective sweep are known, yet each neutrality test only identifies a single signature. We present RAiSD (Raised Accuracy in Sweep Detection), an open-source software that implements a novel, to our knowledge, and parameter-free detection mechanism that relies on multiple signatures of a selective sweep via the enumeration of SNP vectors. RAiSD achieves higher sensitivity and accuracy than the current state of the art, while the computational complexity is greatly reduced, allowing up to 1000 times faster processing than widely used tools, and negligible memory requirements. Nikolaos Alachiotis and Pavlos Pavlidis present RAiSD, a computational method for identifying multiple signatures of selective sweeps using single nucleotide polymorphism vectors. They show that RAiSD has higher sensitivity and accuracy with reduced computational complexity than current methods.
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Affiliation(s)
- Nikolaos Alachiotis
- Institute of Computer Science, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece.
| | - Pavlos Pavlidis
- Institute of Computer Science, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece.
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45
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Torres R, Szpiech ZA, Hernandez RD. Human demographic history has amplified the effects of background selection across the genome. PLoS Genet 2018; 14:e1007387. [PMID: 29912945 PMCID: PMC6056204 DOI: 10.1371/journal.pgen.1007387] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 07/23/2018] [Accepted: 04/30/2018] [Indexed: 01/22/2023] Open
Abstract
Natural populations often grow, shrink, and migrate over time. Such demographic processes can affect genome-wide levels of genetic diversity. Additionally, genetic variation in functional regions of the genome can be altered by natural selection, which drives adaptive mutations to higher frequencies or purges deleterious ones. Such selective processes affect not only the sites directly under selection but also nearby neutral variation through genetic linkage via processes referred to as genetic hitchhiking in the context of positive selection and background selection (BGS) in the context of purifying selection. While there is extensive literature examining the consequences of selection at linked sites at demographic equilibrium, less is known about how non-equilibrium demographic processes influence the effects of hitchhiking and BGS. Utilizing a global sample of human whole-genome sequences from the Thousand Genomes Project and extensive simulations, we investigate how non-equilibrium demographic processes magnify and dampen the consequences of selection at linked sites across the human genome. When binning the genome by inferred strength of BGS, we observe that, compared to Africans, non-African populations have experienced larger proportional decreases in neutral genetic diversity in strong BGS regions. We replicate these findings in admixed populations by showing that non-African ancestral components of the genome have also been affected more severely in these regions. We attribute these differences to the strong, sustained/recurrent population bottlenecks that non-Africans experienced as they migrated out of Africa and throughout the globe. Furthermore, we observe a strong correlation between FST and the inferred strength of BGS, suggesting a stronger rate of genetic drift. Forward simulations of human demographic history with a model of BGS support these observations. Our results show that non-equilibrium demography significantly alters the consequences of selection at linked sites and support the need for more work investigating the dynamic process of multiple evolutionary forces operating in concert.
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Affiliation(s)
- Raul Torres
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, CA, United States of America
| | - Zachary A. Szpiech
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, United States of America
| | - Ryan D. Hernandez
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, United States of America
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, United States of America
- Institute for Computational Health Sciences, University of California San Francisco, San Francisco, CA, United States of America
- Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA, United States of America
- * E-mail:
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46
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Campbell CR, Poelstra JW, Yoder AD. What is Speciation Genomics? The roles of ecology, gene flow, and genomic architecture in the formation of species. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly063] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - J W Poelstra
- Department of Biology, Duke University, Durham, NC, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC, USA
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47
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Hess K, Oliverio R, Nguyen P, Le D, Ellis J, Kdeiss B, Ord S, Chalkia D, Nikolaidis N. Concurrent action of purifying selection and gene conversion results in extreme conservation of the major stress-inducible Hsp70 genes in mammals. Sci Rep 2018; 8:5082. [PMID: 29572464 PMCID: PMC5865164 DOI: 10.1038/s41598-018-23508-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/14/2018] [Indexed: 12/28/2022] Open
Abstract
Several evolutionary mechanisms alter the fate of mutations and genes within populations based on their exhibited functional effects. To understand the underlying mechanisms involved in the evolution of the cellular stress response, a very conserved mechanism in the course of organismal evolution, we studied the patterns of natural genetic variation and functional consequences of polymorphisms of two stress-inducible Hsp70 genes. These genes, HSPA1A and HSPA1B, are major orchestrators of the cellular stress response and are associated with several human diseases. Our phylogenetic analyses revealed that the duplication of HSPA1A and HSPA1B originated in a lineage proceeding to placental mammals, and henceforth they remained in conserved synteny. Additionally, analyses of synonymous and non-synonymous changes suggest that purifying selection shaped the HSPA1 gene diversification, while gene conversion resulted in high sequence conservation within species. In the human HSPA1-cluster, the vast majority of mutations are synonymous and specific genic regions are devoid of mutations. Furthermore, functional characterization of several human polymorphisms revealed subtle differences in HSPA1A stability and intracellular localization. Collectively, the observable patterns of HSPA1A-1B variation describe an evolutionary pattern, in which purifying selection and gene conversion act simultaneously and conserve a major orchestrator of the cellular stress response.
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Affiliation(s)
- Kyle Hess
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA.,Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Ryan Oliverio
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Peter Nguyen
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Dat Le
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Jacqueline Ellis
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Brianna Kdeiss
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Sara Ord
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Dimitra Chalkia
- UCLA Center for Systems Biomedicine, Division of Digestive Diseases, School of Medicine, Los Angeles, CA, USA
| | - Nikolas Nikolaidis
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA.
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48
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Ravinet M, Faria R, Butlin RK, Galindo J, Bierne N, Rafajlović M, Noor MAF, Mehlig B, Westram AM. Interpreting the genomic landscape of speciation: a road map for finding barriers to gene flow. J Evol Biol 2017; 30:1450-1477. [DOI: 10.1111/jeb.13047] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 12/14/2022]
Affiliation(s)
- M. Ravinet
- Centre for Ecological and Evolutionary Synthesis; University of Oslo; Oslo Norway
- National Institute of Genetics; Mishima Shizuoka Japan
| | - R. Faria
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos; InBIO, Laboratório Associado; Universidade do Porto; Vairão Portugal
- Department of Experimental and Health Sciences; IBE, Institute of Evolutionary Biology (CSIC-UPF); Pompeu Fabra University; Barcelona Spain
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
| | - R. K. Butlin
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
- Department of Marine Sciences; Centre for Marine Evolutionary Biology; University of Gothenburg; Gothenburg Sweden
| | - J. Galindo
- Department of Biochemistry, Genetics and Immunology; University of Vigo; Vigo Spain
| | - N. Bierne
- CNRS; Université Montpellier; ISEM; Station Marine Sète France
| | - M. Rafajlović
- Department of Physics; University of Gothenburg; Gothenburg Sweden
| | | | - B. Mehlig
- Department of Physics; University of Gothenburg; Gothenburg Sweden
| | - A. M. Westram
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
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49
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Burri R. Interpreting differentiation landscapes in the light of long-term linked selection. Evol Lett 2017. [DOI: 10.1002/evl3.14] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Reto Burri
- Department of Population Ecology; Friedrich Schiller University Jena; Dornburger Strasse 159 D-07743 Jena Germany
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50
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Vijay N, Weissensteiner M, Burri R, Kawakami T, Ellegren H, Wolf JBW. Genomewide patterns of variation in genetic diversity are shared among populations, species and higher-order taxa. Mol Ecol 2017; 26:4284-4295. [PMID: 28570015 DOI: 10.1111/mec.14195] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 05/10/2017] [Accepted: 05/17/2017] [Indexed: 12/15/2022]
Abstract
Genomewide screens of genetic variation within and between populations can reveal signatures of selection implicated in adaptation and speciation. Genomic regions with low genetic diversity and elevated differentiation reflective of locally reduced effective population sizes (Ne ) are candidates for barrier loci contributing to population divergence. Yet, such candidate genomic regions need not arise as a result of selection promoting adaptation or advancing reproductive isolation. Linked selection unrelated to lineage-specific adaptation or population divergence can generate comparable signatures. It is challenging to distinguish between these processes, particularly when diverging populations share ancestral genetic variation. In this study, we took a comparative approach using population assemblages from distant clades assessing genomic parallelism of variation in Ne . Utilizing population-level polymorphism data from 444 resequenced genomes of three avian clades spanning 50 million years of evolution, we tested whether population genetic summary statistics reflecting genomewide variation in Ne would covary among populations within clades, and importantly, also among clades where lineage sorting has been completed. All statistics including population-scaled recombination rate (ρ), nucleotide diversity (π) and measures of genetic differentiation between populations (FST , PBS, dxy ) were significantly correlated across all phylogenetic distances. Moreover, genomic regions with elevated levels of genetic differentiation were associated with inferred pericentromeric and subtelomeric regions. The phylogenetic stability of diversity landscapes and stable association with genomic features support a role of linked selection not necessarily associated with adaptation and speciation in shaping patterns of genomewide heterogeneity in genetic diversity.
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Affiliation(s)
- Nagarjun Vijay
- Department of Evolutionary Biology and SciLifeLab, Uppsala University, Uppsala, Sweden.,Lab of Molecular and Genomic Evolution, Department of Ecology and Evolutionary Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA
| | - Matthias Weissensteiner
- Department of Evolutionary Biology and SciLifeLab, Uppsala University, Uppsala, Sweden.,Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Reto Burri
- Department of Evolutionary Biology and SciLifeLab, Uppsala University, Uppsala, Sweden.,Department of Population Ecology, Friedrich Schiller University Jena, Jena, Germany
| | - Takeshi Kawakami
- Department of Evolutionary Biology and SciLifeLab, Uppsala University, Uppsala, Sweden.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Hans Ellegren
- Department of Evolutionary Biology and SciLifeLab, Uppsala University, Uppsala, Sweden
| | - Jochen B W Wolf
- Department of Evolutionary Biology and SciLifeLab, Uppsala University, Uppsala, Sweden.,Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
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