1
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Paijmans AJ, Berthelsen AL, Nagel R, Christaller F, Kröcker N, Forcada J, Hoffman JI. Little evidence of inbreeding depression for birth mass, survival and growth in Antarctic fur seal pups. Sci Rep 2024; 14:12610. [PMID: 38824161 PMCID: PMC11144264 DOI: 10.1038/s41598-024-62290-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 05/15/2024] [Indexed: 06/03/2024] Open
Abstract
Inbreeding depression, the loss of offspring fitness due to consanguineous mating, is generally detrimental for individual performance and population viability. We investigated inbreeding effects in a declining population of Antarctic fur seals (Arctocephalus gazella) at Bird Island, South Georgia. Here, localised warming has reduced the availability of the seal's staple diet, Antarctic krill, leading to a temporal increase in the strength of selection against inbred offspring, which are increasingly failing to recruit into the adult breeding population. However, it remains unclear whether selection operates before or after nutritional independence at weaning. We therefore used microsatellite data from 885 pups and their mothers, and SNP array data from 98 mother-offspring pairs, to quantify the effects of individual and maternal inbreeding on three important neonatal fitness traits: birth mass, survival and growth. We did not find any clear or consistent effects of offspring or maternal inbreeding on any of these traits. This suggests that selection filters inbred individuals out of the population as juveniles during the time window between weaning and recruitment. Our study brings into focus a poorly understood life-history stage and emphasises the importance of understanding the ecology and threats facing juvenile pinnipeds.
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Affiliation(s)
- A J Paijmans
- Department of Evolutionary Population Genetics, Bielefeld University, 33615, Bielefeld, Germany.
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany.
| | - A L Berthelsen
- Department of Evolutionary Population Genetics, Bielefeld University, 33615, Bielefeld, Germany
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany
| | - R Nagel
- Department of Evolutionary Population Genetics, Bielefeld University, 33615, Bielefeld, Germany
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany
- Centre for Biological Diversity, University of St. Andrews, St Andrews, KY16 9TH, UK
| | - F Christaller
- Department of Evolutionary Population Genetics, Bielefeld University, 33615, Bielefeld, Germany
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany
| | - N Kröcker
- Department of Evolutionary Population Genetics, Bielefeld University, 33615, Bielefeld, Germany
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany
| | - J Forcada
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 OET, UK
| | - J I Hoffman
- Department of Evolutionary Population Genetics, Bielefeld University, 33615, Bielefeld, Germany
- Department of Animal Behaviour, Bielefeld University, 33501, Bielefeld, Germany
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 OET, UK
- Joint Institute for Individualisation in a Changing Environment (JICE), Bielefeld University and University of Münster, Bielefeld, Germany
- Center for Biotechnology (CeBiTec), Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
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Forcada J, Hoffman JI, Gimenez O, Staniland IJ, Bucktrout P, Wood AG. Ninety years of change, from commercial extinction to recovery, range expansion and decline for Antarctic fur seals at South Georgia. GLOBAL CHANGE BIOLOGY 2023; 29:6867-6887. [PMID: 37839801 DOI: 10.1111/gcb.16947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 10/17/2023]
Abstract
With environmental change, understanding how species recover from overharvesting and maintain viable populations is central to ecosystem restoration. Here, we reconstruct 90 years of recovery trajectory of the Antarctic fur seal at South Georgia (S.W. Atlantic), a key indicator species in the krill-based food webs of the Southern Ocean. After being harvested to commercial extinction by 1907, this population rebounded and now constitutes the most abundant otariid in the World. However, its status remains uncertain due to insufficient and conflicting data, and anthropogenic pressures affecting Antarctic krill, an essential staple for millions of fur seals and other predators. Using integrated population models, we estimated simultaneously the long-term abundance for Bird Island, northwest South Georgia, epicentre of recovery of the species after sealing, and population adjustments for survey counts with spatiotemporal applicability. Applied to the latest comprehensive survey data, we estimated the population at South Georgia in 2007-2009 as 3,510,283 fur seals [95% CI: 3,140,548-3,919,604] (ca. 98% of global population), after 40 years of maximum growth and range expansion owing to an abundant krill supply. At Bird Island, after 50 years of exponential growth followed by 25 years of slow stable growth, the population collapsed in 2009 and has thereafter declined by -7.2% [-5.2, -9.1] per annum, to levels of the 1970s. For the instrumental record, this trajectory correlates with a time-varying relationship between coupled climate and sea surface temperature cycles associated with low regional krill availability, although the effects of increasing krill extraction by commercial fishing and natural competitors remain uncertain. Since 2015, fur seal longevity and recruitment have dropped, sexual maturation has retarded, and population growth is expected to remain mostly negative and highly variable. Our analysis documents the rise and fall of a key Southern Ocean predator over a century of profound environmental and ecosystem change.
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Affiliation(s)
- Jaume Forcada
- British Antarctic Survey, Natural Environment Research Council, UKRI, Cambridge, UK
| | - Joseph I Hoffman
- British Antarctic Survey, Natural Environment Research Council, UKRI, Cambridge, UK
- Department of Animal Behavior, University of Bielefeld, Bielefeld, Germany
| | - Olivier Gimenez
- CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
| | | | - Pete Bucktrout
- British Antarctic Survey, Natural Environment Research Council, UKRI, Cambridge, UK
| | - Andrew G Wood
- British Antarctic Survey, Natural Environment Research Council, UKRI, Cambridge, UK
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3
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Lopes F, Oliveira LR, Beux Y, Kessler A, Cárdenas-Alayza S, Majluf P, Páez-Rosas D, Chaves J, Crespo E, Brownell RL, Baylis AMM, Sepúlveda M, Franco-Trecu V, Loch C, Robertson BC, Peart CR, Wolf JBW, Bonatto SL. Genomic evidence for homoploid hybrid speciation in a marine mammal apex predator. SCIENCE ADVANCES 2023; 9:eadf6601. [PMID: 37134171 PMCID: PMC10156116 DOI: 10.1126/sciadv.adf6601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Hybridization is widespread and constitutes an important source of genetic variability and evolution. In animals, its role in generating novel and independent lineages (hybrid speciation) has been strongly debated, with only a few cases supported by genomic data. The South American fur seal (SAfs) Arctocephalus australis is a marine apex predator of Pacific and Atlantic waters, with a disjunct set of populations in Peru and Northern Chile [Peruvian fur seal (Pfs)] with controversial taxonomic status. We demonstrate, using complete genome and reduced representation sequencing, that the Pfs is a genetically distinct species with an admixed genome that originated from hybridization between the SAfs and the Galapagos fur seal (Arctocephalus galapagoensis) ~400,000 years ago. Our results strongly support the origin of Pfs by homoploid hybrid speciation over alternative introgression scenarios. This study highlights the role of hybridization in promoting species-level biodiversity in large vertebrates.
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Affiliation(s)
- Fernando Lopes
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
- Laboratório de Ecologia de Mamíferos, Universidade do Vale do Rio dos Sinos, São Leopoldo, Brazil
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Larissa R Oliveira
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
- Grupo de Estudos de Mamíferos Aquáticos do Rio Grande do Sul (GEMARS), Torres, Brazil
| | - Yago Beux
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
| | - Amanda Kessler
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
| | - Susana Cárdenas-Alayza
- Centro para la Sostenibilidad Ambiental, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Patricia Majluf
- Centro para la Sostenibilidad Ambiental, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Diego Páez-Rosas
- Colegio de Ciencias Biológicas y Ambientales, COCIBA, Universidad San Francisco de Quito, Quito, Ecuador
- Dirección del Parque Nacional Galápagos, Oficina Técnica San Cristobal, Islas Galápagos, Ecuador
| | - Jaime Chaves
- Colegio de Ciencias Biológicas y Ambientales, COCIBA, Universidad San Francisco de Quito, Quito, Ecuador
- Galapagos Science Center, Puerto Baquerizo Moreno, Ecuador
- Department of Biology, San Francisco State University, 1800 Holloway Ave, San Francisco, CA, USA
| | - Enrique Crespo
- Laboratório de Mamíferos Marinos, CESIMAR - CCT CENPAT, CONICET, Puerto Madryn, Argentina
| | - Robert L Brownell
- Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, CA, USA
| | | | - Maritza Sepúlveda
- Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Valentina Franco-Trecu
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | | | - Claire R Peart
- Division of Evolutionary Biology, LMU Munich, München, Germany
| | - Jochen B W Wolf
- Division of Evolutionary Biology, LMU Munich, München, Germany
| | - Sandro L Bonatto
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
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4
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Intronic primers reveal unexpectedly high major histocompatibility complex diversity in Antarctic fur seals. Sci Rep 2022; 12:17933. [PMID: 36289307 PMCID: PMC9606363 DOI: 10.1038/s41598-022-21658-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/29/2022] [Indexed: 01/20/2023] Open
Abstract
The major histocompatibility complex (MHC) is a group of genes comprising one of the most important components of the vertebrate immune system. Consequently, there has been much interest in characterising MHC variation and its relationship with fitness in a variety of species. Due to the exceptional polymorphism of MHC genes, careful PCR primer design is crucial for capturing all of the allelic variation present in a given species. We therefore developed intronic primers to amplify the full-length 267 bp protein-coding sequence of the MHC class II DQB exon 2 in the Antarctic fur seal. We then characterised patterns of MHC variation among mother-offspring pairs from two breeding colonies and detected 19 alleles among 771 clone sequences from 56 individuals. The distribution of alleles within and among individuals was consistent with a single-copy, classical DQB locus showing Mendelian inheritance. Amino acid similarity at the MHC was significantly associated with genome-wide relatedness, but no relationship was found between MHC heterozygosity and genome-wide heterozygosity. Finally, allelic diversity was several times higher than reported by a previous study based on partial exon sequences. This difference appears to be related to allele-specific amplification bias, implying that primer design can strongly impact the inference of MHC diversity.
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Malan A, von der Heyden S, Herron S, Arnould JPY, Kirkwood R, Matthee CA. Palaeoclimatic changes resulted in range expansion and subsequent divergence in brown fur seals, Arctocephalus pusillus. Biol Lett 2022; 18:20220285. [PMID: 36043305 PMCID: PMC9428522 DOI: 10.1098/rsbl.2022.0285] [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: 06/23/2022] [Accepted: 08/11/2022] [Indexed: 11/12/2022] Open
Abstract
Past climatic change as a driving force of marine diversification is still largely unclear, particularly for Southern Hemisphere species. Here, we present a case using the brown fur seal, Arctocephalus pusillus, assessing the geographical structure and demographic history using mitochondrial and nuclear data. Results show the two previously defined subspecies (one from Australia and the other from southern Africa) are phylogeographically distinct. Migration analyses based on nuclear data suggest the absence of migrants among the two genetically close assemblages. The demographic history of A. pusillus is characterized by a glacial population expansion (approx. 18 kya) in the southern African lineage, which coincides with time estimates of population expansion of prey species of seals. Approximate Bayesian calculations support an eastward dispersal event during the Last Glacial Maximum when sea levels were lower, followed by a postglacial divergence event, approximately 13 kya. The demographic history of the brown fur seal in the Southern Oceans provides support that recent palaeoclimatic changes could have facilitated expansions in some marine species and that postglacial sea-level rise may have acted as a dispersal barrier for species mostly confined to continental shelves.
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Affiliation(s)
- A. Malan
- Department Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - S. von der Heyden
- Department Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - S. Herron
- Department Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - J. P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - R. Kirkwood
- South Australian Research and Development Institute, Aquatic Sciences, West Beach, South Australia 5024, Australia
- Research Department, Phillip Island Nature Parks, Cowes, Victoria 3922, Australia
| | - C. A. Matthee
- Department Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa
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6
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Pearman WS, Urban L, Alexander A. Commonly used Hardy-Weinberg equilibrium filtering schemes impact population structure inferences using RADseq data. Mol Ecol Resour 2022; 22:2599-2613. [PMID: 35593534 PMCID: PMC9541430 DOI: 10.1111/1755-0998.13646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 05/13/2022] [Indexed: 11/29/2022]
Abstract
Reduced representation sequencing (RRS) is a widely used method to assay the diversity of genetic loci across the genome of an organism. The dominant class of RRS approaches assay loci associated with restriction sites within the genome (restriction site associated DNA sequencing, or RADseq). RADseq is frequently applied to non‐model organisms since it enables population genetic studies without relying on well‐characterized reference genomes. However, RADseq requires the use of many bioinformatic filters to ensure the quality of genotyping calls. These filters can have direct impacts on population genetic inference, and therefore require careful consideration. One widely used filtering approach is the removal of loci that do not conform to expectations of Hardy–Weinberg equilibrium (HWE). Despite being widely used, we show that this filtering approach is rarely described in sufficient detail to enable replication. Furthermore, through analyses of in silico and empirical data sets we show that some of the most widely used HWE filtering approaches dramatically impact inference of population structure. In particular, the removal of loci exhibiting departures from HWE after pooling across samples significantly reduces the degree of inferred population structure within a data set (despite this approach being widely used). Based on these results, we provide recommendations for best practice regarding the implementation of HWE filtering for RADseq data sets.
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Affiliation(s)
- William S Pearman
- Department of Marine Science, University of Otago, Dunedin, New Zealand.,Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Lara Urban
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Alana Alexander
- Department of Anatomy, University of Otago, Dunedin, New Zealand
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7
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Demographic Reconstruction of Antarctic Fur Seals Supports the Krill Surplus Hypothesis. Genes (Basel) 2022; 13:genes13030541. [PMID: 35328094 PMCID: PMC8954904 DOI: 10.3390/genes13030541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/10/2022] [Indexed: 11/16/2022] Open
Abstract
Much debate surrounds the importance of top-down and bottom-up effects in the Southern Ocean, where the harvesting of over two million whales in the mid twentieth century is thought to have produced a massive surplus of Antarctic krill. This excess of krill may have allowed populations of other predators, such as seals and penguins, to increase, a top-down hypothesis known as the ‘krill surplus hypothesis’. However, a lack of pre-whaling population baselines has made it challenging to investigate historical changes in the abundance of the major krill predators in relation to whaling. Therefore, we used reduced representation sequencing and a coalescent-based maximum composite likelihood approach to reconstruct the recent demographic history of the Antarctic fur seal, a pinniped that was hunted to the brink of extinction by 18th and 19th century sealers. In line with the known history of this species, we found support for a demographic model that included a substantial reduction in population size around the time period of sealing. Furthermore, maximum likelihood estimates from this model suggest that the recovered, post-sealing population at South Georgia may have been around two times larger than the pre-sealing population. Our findings lend support to the krill surplus hypothesis and illustrate the potential of genomic approaches to shed light on long-standing questions in population biology.
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Noh HJ, Turner-Maier J, Schulberg SA, Fitzgerald ML, Johnson J, Allen KN, Hückstädt LA, Batten AJ, Alfoldi J, Costa DP, Karlsson EK, Zapol WM, Buys ES, Lindblad-Toh K, Hindle AG. The Antarctic Weddell seal genome reveals evidence of selection on cardiovascular phenotype and lipid handling. Commun Biol 2022; 5:140. [PMID: 35177770 PMCID: PMC8854659 DOI: 10.1038/s42003-022-03089-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/31/2022] [Indexed: 12/24/2022] Open
Abstract
AbstractThe Weddell seal (Leptonychotes weddellii) thrives in its extreme Antarctic environment. We generated the Weddell seal genome assembly and a high-quality annotation to investigate genome-wide evolutionary pressures that underlie its phenotype and to study genes implicated in hypoxia tolerance and a lipid-based metabolism. Genome-wide analyses included gene family expansion/contraction, positive selection, and diverged sequence (acceleration) compared to other placental mammals, identifying selection in coding and non-coding sequence in five pathways that may shape cardiovascular phenotype. Lipid metabolism as well as hypoxia genes contained more accelerated regions in the Weddell seal compared to genomic background. Top-significant genes were SUMO2 and EP300; both regulate hypoxia inducible factor signaling. Liver expression of four genes with the strongest acceleration signals differ between Weddell seals and a terrestrial mammal, sheep. We also report a high-density lipoprotein-like particle in Weddell seal serum not present in other mammals, including the shallow-diving harbor seal.
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Yuan Y, Seim I, Hoelzel AR, Zhang Y, Zhang P, Kang H, Wang D, Fan G, Wang K, Li S. Reply to Gaudry et al.: Cross-validation is necessary for the identification of pseudogenes. Proc Natl Acad Sci U S A 2022; 119:e2120427119. [PMID: 35101989 PMCID: PMC8833181 DOI: 10.1073/pnas.2120427119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Yuan Yuan
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - A Rus Hoelzel
- Department of Biosciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Yaolei Zhang
- BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- BGI-Shenzhen, Shenzhen 518083, China
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby 2800, Denmark
| | - Peijun Zhang
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Hui Kang
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Ding Wang
- Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Guangyi Fan
- BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- BGI-Shenzhen, Shenzhen 518083, China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China
| | - Kun Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China;
| | - Songhai Li
- Marine Mammal and Marine Bioacoustics Laboratory, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China;
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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10
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Foster Y, Dutoit L, Grosser S, Dussex N, Foster BJ, Dodds KG, Brauning R, Van Stijn T, Robertson F, McEwan JC, Jacobs JME, Robertson BC. Genomic signatures of inbreeding in a critically endangered parrot, the kākāpō. G3 (BETHESDA, MD.) 2021; 11:jkab307. [PMID: 34542587 PMCID: PMC8527487 DOI: 10.1093/g3journal/jkab307] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/23/2021] [Indexed: 02/06/2023]
Abstract
Events of inbreeding are inevitable in critically endangered species. Reduced population sizes and unique life-history traits can increase the severity of inbreeding, leading to declines in fitness and increased risk of extinction. Here, we investigate levels of inbreeding in a critically endangered flightless parrot, the kākāpō (Strigops habroptilus), wherein a highly inbred island population and one individual from the mainland of New Zealand founded the entire extant population. Genotyping-by-sequencing (GBS), and a genotype calling approach using a chromosome-level genome assembly, identified a filtered set of 12,241 single-nucleotide polymorphisms (SNPs) among 161 kākāpō, which together encompass the total genetic potential of the extant population. Multiple molecular-based estimates of inbreeding were compared, including genome-wide estimates of heterozygosity (FH), the diagonal elements of a genomic-relatedness matrix (FGRM), and runs of homozygosity (RoH, FRoH). In addition, we compared levels of inbreeding in chicks from a recent breeding season to examine if inbreeding is associated with offspring survival. The density of SNPs generated with GBS was sufficient to identify chromosomes that were largely homozygous with RoH distributed in similar patterns to other inbred species. Measures of inbreeding were largely correlated and differed significantly between descendants of the two founding populations. However, neither inbreeding nor ancestry was found to be associated with reduced survivorship in chicks, owing to unexpected mortality in chicks exhibiting low levels of inbreeding. Our study highlights important considerations for estimating inbreeding in critically endangered species, such as the impacts of small population sizes and admixture between diverse lineages.
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Affiliation(s)
- Yasmin Foster
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
| | - Ludovic Dutoit
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
| | - Stefanie Grosser
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
| | - Nicolas Dussex
- Centre for Palaeogenetics, SE-106 91 Stockholm, Sweden
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden
- Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Brodie J Foster
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
| | - Ken G Dodds
- AgResearch Invermay Agricultural Centre, Mosgiel 9053, New Zealand
| | - Rudiger Brauning
- AgResearch Invermay Agricultural Centre, Mosgiel 9053, New Zealand
| | - Tracey Van Stijn
- AgResearch Invermay Agricultural Centre, Mosgiel 9053, New Zealand
| | - Fiona Robertson
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
| | - John C McEwan
- AgResearch Invermay Agricultural Centre, Mosgiel 9053, New Zealand
| | | | - Bruce C Robertson
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
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11
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Peart CR, Williams C, Pophaly SD, Neely BA, Gulland FMD, Adams DJ, Ng BL, Cheng W, Goebel ME, Fedrigo O, Haase B, Mountcastle J, Fungtammasan A, Formenti G, Collins J, Wood J, Sims Y, Torrance J, Tracey A, Howe K, Rhie A, Hoffman JI, Johnson J, Jarvis ED, Breen M, Wolf JBW. Hi-C scaffolded short- and long-read genome assemblies of the California sea lion are broadly consistent for syntenic inference across 45 million years of evolution. Mol Ecol Resour 2021; 21:2455-2470. [PMID: 34097816 PMCID: PMC9732816 DOI: 10.1111/1755-0998.13443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/06/2021] [Accepted: 05/26/2021] [Indexed: 12/13/2022]
Abstract
With the advent of chromatin-interaction maps, chromosome-level genome assemblies have become a reality for a wide range of organisms. Scaffolding quality is, however, difficult to judge. To explore this gap, we generated multiple chromosome-scale genome assemblies of an emerging wild animal model for carcinogenesis, the California sea lion (Zalophus californianus). Short-read assemblies were scaffolded with two independent chromatin interaction mapping data sets (Hi-C and Chicago), and long-read assemblies with three data types (Hi-C, optical maps and 10X linked reads) following the "Vertebrate Genomes Project (VGP)" pipeline. In both approaches, 18 major scaffolds recovered the karyotype (2n = 36), with scaffold N50s of 138 and 147 Mb, respectively. Synteny relationships at the chromosome level with other pinniped genomes (2n = 32-36), ferret (2n = 34), red panda (2n = 36) and domestic dog (2n = 78) were consistent across approaches and recovered known fissions and fusions. Comparative chromosome painting and multicolour chromosome tiling with a panel of 264 genome-integrated single-locus canine bacterial artificial chromosome probes provided independent evaluation of genome organization. Broad-scale discrepancies between the approaches were observed within chromosomes, most commonly in translocations centred around centromeres and telomeres, which were better resolved in the VGP assembly. Genomic and cytological approaches agreed on near-perfect synteny of the X chromosome, and in combination allowed detailed investigation of autosomal rearrangements between dog and sea lion. This study presents high-quality genomes of an emerging cancer model and highlights that even highly fragmented short-read assemblies scaffolded with Hi-C can yield reliable chromosome-level scaffolds suitable for comparative genomic analyses.
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Affiliation(s)
- Claire R. Peart
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Munchen, Germany
| | - Christina Williams
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Saurabh D. Pophaly
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Munchen, Germany,Max Planck institute for Plant Breeding Research, Cologne, Germany
| | - Benjamin A. Neely
- National Institute of Standards and Technology, NIST Charleston, Charleston, South Carolina, USA
| | - Frances M. D. Gulland
- Karen Dryer Wildlife Health Center, University of California Davis, Davis, California, USA
| | - David J. Adams
- Cytometry Core Facility, Wellcome Sanger Institute, Cambridge, UK
| | - Bee Ling Ng
- Cytometry Core Facility, Wellcome Sanger Institute, Cambridge, UK
| | - William Cheng
- Cytometry Core Facility, Wellcome Sanger Institute, Cambridge, UK
| | - Michael E. Goebel
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, California, USA
| | - Olivier Fedrigo
- Vertebrate Genome Lab, The Rockefeller University, New York City, New York, USA
| | - Bettina Haase
- Vertebrate Genome Lab, The Rockefeller University, New York City, New York, USA
| | | | | | - Giulio Formenti
- Vertebrate Genome Lab, The Rockefeller University, New York City, New York, USA,Laboratory of Neurogenetics of Language, The Rockefeller University, New York City, New York, USA
| | - Joanna Collins
- Tree of Life Programme, Wellcome Sanger Institute, Cambridge, UK
| | - Jonathan Wood
- Tree of Life Programme, Wellcome Sanger Institute, Cambridge, UK
| | - Ying Sims
- Tree of Life Programme, Wellcome Sanger Institute, Cambridge, UK
| | - James Torrance
- Tree of Life Programme, Wellcome Sanger Institute, Cambridge, UK
| | - Alan Tracey
- Tree of Life Programme, Wellcome Sanger Institute, Cambridge, UK
| | - Kerstin Howe
- Tree of Life Programme, Wellcome Sanger Institute, Cambridge, UK
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA
| | - Joseph I. Hoffman
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany,British Antarctic Survey, Cambridge, UK
| | - Jeremy Johnson
- Broad Institute of Harvard and Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA
| | - Erich D. Jarvis
- Vertebrate Genome Lab, The Rockefeller University, New York City, New York, USA,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Matthew Breen
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, USA
| | - Jochen B. W. Wolf
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Munchen, Germany
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12
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Christiansen H, Heindler FM, Hellemans B, Jossart Q, Pasotti F, Robert H, Verheye M, Danis B, Kochzius M, Leliaert F, Moreau C, Patel T, Van de Putte AP, Vanreusel A, Volckaert FAM, Schön I. Facilitating population genomics of non-model organisms through optimized experimental design for reduced representation sequencing. BMC Genomics 2021; 22:625. [PMID: 34418978 PMCID: PMC8380342 DOI: 10.1186/s12864-021-07917-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/26/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Genome-wide data are invaluable to characterize differentiation and adaptation of natural populations. Reduced representation sequencing (RRS) subsamples a genome repeatedly across many individuals. However, RRS requires careful optimization and fine-tuning to deliver high marker density while being cost-efficient. The number of genomic fragments created through restriction enzyme digestion and the sequencing library setup must match to achieve sufficient sequencing coverage per locus. Here, we present a workflow based on published information and computational and experimental procedures to investigate and streamline the applicability of RRS. RESULTS In an iterative process genome size estimates, restriction enzymes and size selection windows were tested and scaled in six classes of Antarctic animals (Ostracoda, Malacostraca, Bivalvia, Asteroidea, Actinopterygii, Aves). Achieving high marker density would be expensive in amphipods, the malacostracan target taxon, due to the large genome size. We propose alternative approaches such as mitogenome or target capture sequencing for this group. Pilot libraries were sequenced for all other target taxa. Ostracods, bivalves, sea stars, and fish showed overall good coverage and marker numbers for downstream population genomic analyses. In contrast, the bird test library produced low coverage and few polymorphic loci, likely due to degraded DNA. CONCLUSIONS Prior testing and optimization are important to identify which groups are amenable for RRS and where alternative methods may currently offer better cost-benefit ratios. The steps outlined here are easy to follow for other non-model taxa with little genomic resources, thus stimulating efficient resource use for the many pressing research questions in molecular ecology.
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Affiliation(s)
- Henrik Christiansen
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium.
| | - Franz M Heindler
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Bart Hellemans
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Quentin Jossart
- Marine Biology Group, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | | | - Henri Robert
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Marie Verheye
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Bruno Danis
- Marine Biology Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Marc Kochzius
- Marine Biology Group, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Frederik Leliaert
- Marine Biology Research Group, Ghent University, Ghent, Belgium.,Meise Botanic Garden, Meise, Belgium
| | - Camille Moreau
- Marine Biology Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium.,Université de Bourgogne Franche-Comté (UBFC) UMR CNRS 6282 Biogéosciences, Dijon, France
| | - Tasnim Patel
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Anton P Van de Putte
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium.,OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Marine Biology Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Ann Vanreusel
- Marine Biology Research Group, Ghent University, Ghent, Belgium
| | - Filip A M Volckaert
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Isa Schön
- OD Nature, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
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13
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Lopes F, Oliveira LR, Kessler A, Beux Y, Crespo E, Cárdenas-Alayza S, Majluf P, Sepúlveda M, Brownell RL, Franco-Trecu V, Páez-Rosas D, Chaves J, Loch C, Robertson BC, Acevedo-Whitehouse K, Elorriaga-Verplancken FR, Kirkman SP, Peart CR, Wolf JBW, Bonatto SL. Phylogenomic Discordance in the Eared Seals is best explained by Incomplete Lineage Sorting following Explosive Radiation in the Southern Hemisphere. Syst Biol 2020; 70:786-802. [PMID: 33367817 DOI: 10.1093/sysbio/syaa099] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance because of strong gene-tree species tree discordance. Divergence times estimates in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here, we used high-coverage genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus. Our data support a relatively recent trans-hemispheric dispersal at the base of a southern clade, which rapidly diversified into six major lineages between 3 and 2.5 Ma. Otaria diverged first, followed by Phocarctos and then four major lineages within Arctocephalus. However, we found Zalophus to be nonmonophyletic, with California (Zalophus californianus) and Steller sea lions (Eumetopias jubatus) grouping closer than the Galapagos sea lion (Zalophus wollebaeki) with evidence for introgression between the two genera. Overall, the high degree of genealogical discordance was best explained by incomplete lineage sorting resulting from quasi-simultaneous speciation within the southern clade with introgresssion playing a subordinate role in explaining the incongruence among and within prior phylogenetic studies of the family. [Hybridization; ILS; phylogenomics; Pleistocene; Pliocene; monophyly.].
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Affiliation(s)
- Fernando Lopes
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900 Porto Alegre, RS, Brazil.,Laboratório de Ecologia de Mamíferos, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS, Brazil
| | - Larissa R Oliveira
- Laboratório de Ecologia de Mamíferos, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS, Brazil.,GEMARS, Grupo de Estudos de Mamíferos Aquáticos do Rio Grande do Sul, 95560-000 Torres, RS, Brazil
| | - Amanda Kessler
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900 Porto Alegre, RS, Brazil
| | - Yago Beux
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900 Porto Alegre, RS, Brazil
| | - Enrique Crespo
- Centro Nacional Patagónico - CENPAT, CONICET, Puerto Madryn, Argentina
| | - Susana Cárdenas-Alayza
- Centro para la Sostenibilidad Ambiental, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Patricia Majluf
- Centro para la Sostenibilidad Ambiental, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Maritza Sepúlveda
- Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Robert L Brownell
- Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration, NOAA, La Jolla, USA
| | - Valentina Franco-Trecu
- Departamento de Ecología y Evolución, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Diego Páez-Rosas
- Colegio de Ciencias Biológicas y Ambientales, COCIBA, Universidad San Francisco de Quito, Quito, Ecuador
| | - Jaime Chaves
- Colegio de Ciencias Biológicas y Ambientales, COCIBA, Universidad San Francisco de Quito, Quito, Ecuador.,Department of Biology, San Francisco State University, 1800 Holloway Ave, San Francisco, CA, USA
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | | | - Karina Acevedo-Whitehouse
- Unit for Basic and Applied Microbiology, School of Natural Sciences, Universidad Autónoma de Querétaro, Querétaro, Mexico
| | | | - Stephen P Kirkman
- Department of Environmental Affairs, Oceans and Coasts, Cape Town, South Africa
| | - Claire R Peart
- Department Biologie II, Division of Evolutionary Biology, Ludwig-Maximilians-Universität München, Münich, Germany
| | - Jochen B W Wolf
- Department Biologie II, Division of Evolutionary Biology, Ludwig-Maximilians-Universität München, Münich, Germany
| | - Sandro L Bonatto
- Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, 90619-900 Porto Alegre, RS, Brazil
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14
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An 85K SNP Array Uncovers Inbreeding and Cryptic Relatedness in an Antarctic Fur Seal Breeding Colony. G3-GENES GENOMES GENETICS 2020; 10:2787-2799. [PMID: 32540866 PMCID: PMC7407454 DOI: 10.1534/g3.120.401268] [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: 12/14/2022]
Abstract
High density single nucleotide polymorphism (SNP) arrays allow large numbers of individuals to be rapidly and cost-effectively genotyped at large numbers of genetic markers. However, despite being widely used in studies of humans and domesticated plants and animals, SNP arrays are lacking for most wild organisms. We developed a custom 85K Affymetrix Axiom array for an intensively studied pinniped, the Antarctic fur seal (Arctocephalus gazella). SNPs were discovered from a combination of genomic and transcriptomic resources and filtered according to strict criteria. Out of a total of 85,359 SNPs tiled on the array, 75,601 (88.6%) successfully converted and were polymorphic in 270 animals from a breeding colony at Bird Island in South Georgia. Evidence was found for inbreeding, with three genomic inbreeding coefficients being strongly intercorrelated and the proportion of the genome in runs of homozygosity being non-zero in all individuals. Furthermore, analysis of genomic relatedness coefficients identified previously unknown first-degree relatives and multiple second-degree relatives among a sample of ostensibly unrelated individuals. Such “cryptic relatedness” within fur seal breeding colonies may increase the likelihood of consanguineous matings and could therefore have implications for understanding fitness variation and mate choice. Finally, we demonstrate the cross-amplification potential of the array in three related pinniped species. Overall, our SNP array will facilitate future studies of Antarctic fur seals and has the potential to serve as a more general resource for the wider pinniped research community.
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15
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Determinants of genetic variation across eco-evolutionary scales in pinnipeds. Nat Ecol Evol 2020; 4:1095-1104. [PMID: 32514167 DOI: 10.1038/s41559-020-1215-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 04/28/2020] [Indexed: 11/09/2022]
Abstract
The effective size of a population (Ne), which determines its level of neutral variability, is a key evolutionary parameter. Ne can substantially depart from census sizes of present-day breeding populations (NC) as a result of past demographic changes, variation in life-history traits and selection at linked sites. Using genome-wide data we estimated the long-term coalescent Ne for 17 pinniped species represented by 36 population samples (total n = 458 individuals). Ne estimates ranged from 8,936 to 91,178, were highly consistent within (sub)species and showed a strong positive correlation with NC ([Formula: see text] = 0.59; P = 0.0002). Ne/NC ratios were low (mean, 0.31; median, 0.13) and co-varied strongly with demographic history and, to a lesser degree, with species' ecological and life-history variables such as breeding habitat. Residual variation in Ne/NC, after controlling for past demographic fluctuations, contained information about recent population size changes during the Anthropocene. Specifically, species of conservation concern typically had positive residuals indicative of a smaller contemporary NC than would be expected from their long-term Ne. This study highlights the value of comparative population genomic analyses for gauging the evolutionary processes governing genetic variation in natural populations, and provides a framework for identifying populations deserving closer conservation attention.
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16
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Mynhardt S, Bennett NC, Bloomer P. New insights from RADseq data on differentiation in the Hottentot golden mole species complex from South Africa. Mol Phylogenet Evol 2019; 143:106667. [PMID: 31676418 DOI: 10.1016/j.ympev.2019.106667] [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: 03/15/2019] [Revised: 10/28/2019] [Accepted: 10/28/2019] [Indexed: 10/25/2022]
Abstract
Golden moles (Family Chrysochloridae) are small subterranean mammals, endemic to sub-Saharan Africa, and many of the 21 species are listed as threatened on the IUCN Red List. Most species have highly restricted ranges; however two species, the Hottentot golden mole (Amblysomus hottentotus) and the Cape golden mole (Chrysochloris asiatica) have relatively wide ranges. We recently uncovered cryptic diversity within A. hottentotus, through a phylogeographic analysis of this taxon using two mitochondrial gene regions and a nuclear intron. To further investigate this cryptic diversity, we generated nuclear SNP data from across the genome of A. hottentotus, by means of double-digest restriction-site associated DNA sequencing (ddRADSeq), and mapped reads to the Cape golden mole genome. We conducted a phylogenetic analysis and investigated population differentiation. Our results support the distinctiveness of A. h. meesteri. Furthermore, we provide evidence from nuclear SNPs in support of our previous finding that Central coastal samples represent a unique cryptic lineage that is highly divergent from A. h. pondoliae farther south. Although mtDNA suggests that Umtata may represent a unique lineage sister to A. h. longiceps, mito-nuclear discordance from our RADseq data indicate that these samples may instead be closer to A. h. pondoliae, and therefore may not represent a distinct lineage. We stress the importance of recognizing that understudied populations, such as that of Umtata, may represent populations or ESUs under threat and in need of conservation attention. We present a high-quality filtered SNP dataset, comprising thousands of SNPs, which may serve as a useful resource for future golden mole studies. We have thus added to the growing body of research demonstrating the power and utility of RADseq to investigate population differentiation.
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Affiliation(s)
- Samantha Mynhardt
- Molecular Ecology and Evolution Programme, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
| | - Nigel C Bennett
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
| | - Paulette Bloomer
- Molecular Ecology and Evolution Programme, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
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17
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Exploring the Phylogeography of Ancient Platycladus orientalis in China by Specific-Locus Amplified Fragment Sequencing. Int J Mol Sci 2019; 20:ijms20163871. [PMID: 31398898 PMCID: PMC6719015 DOI: 10.3390/ijms20163871] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
Platycladus orientalis (i.e., Chinese thuja) is famous for its lifespan spanning hundreds, and even thousands, of years. Most ancient P. orientalis populations are widely distributed in China, with accessible historical records, making them valuable genetic resources. In this study, the distribution pattern of ancient P. orientalis in China was analyzed based on 13 bioclimatic factors. Additionally, a specific-locus amplified fragment (SLAF) sequencing method was applied to detect single nucleotide polymorphisms (SNPs) in the genomes of 100 accessions from 13 populations. The resulting data revealed that the suitable areas for the distribution of ancient P. orientalis populations were accurately predicted with four main climatic factors. A total of 81,722 SNPs were identified from 461,867 SLAFs for 100 individuals, with an average sequencing depth of 10.11-fold and a Q30 value of 82.75%. The pair-wise genetic distance and genetic differentiation of 13 populations indicated that the BT-T population exhibited the largest divergence from the other populations. A neighbor-joining phylogenetic tree suggested the relationship between many individuals was inconsistent with the geographical location, possibly indicative of a history of transplantation and cultivation. All individuals were clustered into nine genotypes according to a structural analysis and the relationships between individuals were clarified in phylogenetic trees. This study highlights the importance of the de novo genome sequencing of ancient P. orientalis and may provide the basis for the conservation of P. orientalis genetic resources, the identification of supergene families, and the evaluation of related genetic resources.
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18
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Litzke V, Ottensmann M, Forcada J, Heitzmann L, Ivan Hoffman J. Heterozygosity at neutral and immune loci is not associated with neonatal mortality due to microbial infection in Antarctic fur seals. Ecol Evol 2019; 9:7985-7996. [PMID: 31380066 PMCID: PMC6662382 DOI: 10.1002/ece3.5317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/02/2019] [Accepted: 05/08/2019] [Indexed: 11/08/2022] Open
Abstract
Numerous studies have reported correlations between the heterozygosity of genetic markers and fitness. These heterozygosity-fitness correlations (HFCs) play a central role in evolutionary and conservation biology, yet their mechanistic basis remains open to debate. For example, fitness associations have been widely reported at both neutral and functional loci, yet few studies have directly compared the two, making it difficult to gauge the relative contributions of genome-wide inbreeding and specific functional genes to fitness. Here, we compared the effects of neutral and immune gene heterozygosity on death from bacterial infection in Antarctic fur seal (Arctocephalus gazella) pups. We specifically developed a panel of 13 microsatellites from expressed immune genes and genotyped these together with 48 neutral loci in 234 individuals, comprising 39 pups that were classified at necropsy as having most likely died of bacterial infection together with a five times larger matched sample of healthy surviving pups. Identity disequilibrium quantified from the neutral markers was positive and significant, indicative of variance in inbreeding within the study population. However, multilocus heterozygosity did not differ significantly between healthy and infected pups at either class of marker, and little evidence was found for fitness associations at individual loci. These results support a previous study of Antarctic fur seals that found no effects of heterozygosity at nine neutral microsatellites on neonatal survival and thereby help to refine our understanding of how HFCs vary across the life cycle. Given that nonsignificant HFCs are underreported in the literature, we also hope that our study will contribute toward a more balanced understanding of the wider importance of this phenomenon.
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Affiliation(s)
- Vivienne Litzke
- Department of Animal BehaviourBielefeld UniversityBielefeldGermany
| | | | | | | | - Joseph Ivan Hoffman
- Department of Animal BehaviourBielefeld UniversityBielefeldGermany
- British Antarctic Survey, High CrossCambridgeUK
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19
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Grosser S, Sauer J, Paijmans AJ, Caspers BA, Forcada J, Wolf JBW, Hoffman JI. Fur seal microbiota are shaped by the social and physical environment, show mother–offspring similarities and are associated with host genetic quality. Mol Ecol 2019; 28:2406-2422. [DOI: 10.1111/mec.15070] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 02/26/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Stefanie Grosser
- Department of Animal Behaviour Bielefeld University Bielefeld Germany
- Division of Evolutionary Biology, Faculty of Biology LMU Munich Planegg‐Martinsried Germany
| | - Jan Sauer
- Department of Animal Behaviour Bielefeld University Bielefeld Germany
| | | | | | - Jaume Forcada
- British Antarctic Survey Natural Environment Research Council Cambridge UK
| | - Jochen B. W. Wolf
- Division of Evolutionary Biology, Faculty of Biology LMU Munich Planegg‐Martinsried Germany
- Department of Evolutionary Biology Uppsala University Uppsala Sweden
| | - Joseph I. Hoffman
- Department of Animal Behaviour Bielefeld University Bielefeld Germany
- British Antarctic Survey Natural Environment Research Council Cambridge UK
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20
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Experimental validation of in silico predicted RAD locus frequencies using genomic resources and short read data from a model marine mammal. BMC Genomics 2019; 20:72. [PMID: 30669975 PMCID: PMC6341687 DOI: 10.1186/s12864-019-5440-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 01/08/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Restriction site-associated DNA sequencing (RADseq) has revolutionized the study of wild organisms by allowing cost-effective genotyping of thousands of loci. However, for species lacking reference genomes, it can be challenging to select the restriction enzyme that offers the best balance between the number of obtained RAD loci and depth of coverage, which is crucial for a successful outcome. To address this issue, PredRAD was recently developed, which uses probabilistic models to predict restriction site frequencies from a transcriptome assembly or other sequence resource based on either GC content or mono-, di- or trinucleotide composition. This program generates predictions that are broadly consistent with estimates of the true number of restriction sites obtained through in silico digestion of available reference genome assemblies. However, in practice the actual number of loci obtained could potentially differ as incomplete enzymatic digestion or patchy sequence coverage across the genome might lead to some loci not being represented in a RAD dataset, while erroneous assembly could potentially inflate the number of loci. To investigate this, we used genome and transcriptome assemblies together with RADseq data from the Antarctic fur seal (Arctocephalus gazella) to compare PredRAD predictions with empirical estimates of the number of loci obtained via in silico digestion and from de novo assemblies. RESULTS PredRAD yielded consistently higher predicted numbers of restriction sites for the transcriptome assembly relative to the genome assembly. The trinucleotide and dinucleotide models also predicted higher frequencies than the mononucleotide or GC content models. Overall, the dinucleotide and trinucleotide models applied to the transcriptome and the genome assemblies respectively generated predictions that were closest to the number of restriction sites estimated by in silico digestion. Furthermore, the number of de novo assembled RAD loci mapping to restriction sites was similar to the expectation based on in silico digestion. CONCLUSIONS Our study reveals generally high concordance between PredRAD predictions and empirical estimates of the number of RAD loci. This further supports the utility of PredRAD, while also suggesting that it may be feasible to sequence and assemble the majority of RAD loci present in an organism's genome.
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21
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Hoffman JI, Bauer E, Paijmans AJ, Humble E, Beckmann LM, Kubetschek C, Christaller F, Kröcker N, Fuchs B, Moreras A, Shihlomule YD, Bester MN, Cleary AC, De Bruyn PJN, Forcada J, Goebel ME, Goldsworthy SD, Guinet C, Hoelzel AR, Lydersen C, Kovacs KM, Lowther A. A global cline in a colour polymorphism suggests a limited contribution of gene flow towards the recovery of a heavily exploited marine mammal. ROYAL SOCIETY OPEN SCIENCE 2018; 5:181227. [PMID: 30473858 PMCID: PMC6227926 DOI: 10.1098/rsos.181227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/18/2018] [Indexed: 06/09/2023]
Abstract
Evaluating how populations are connected by migration is important for understanding species resilience because gene flow can facilitate recovery from demographic declines. We therefore investigated the extent to which migration may have contributed to the global recovery of the Antarctic fur seal (Arctocephalus gazella), a circumpolar distributed marine mammal that was brought to the brink of extinction by the sealing industry in the eighteenth and nineteenth centuries. It is widely believed that animals emigrating from South Georgia, where a relict population escaped sealing, contributed to the re-establishment of formerly occupied breeding colonies across the geographical range of the species. To investigate this, we interrogated a genetic polymorphism (S291F) in the melanocortin 1 receptor gene, which is responsible for a cream-coloured phenotype that is relatively abundant at South Georgia and which appears to have recently spread to localities as far afield as Marion Island in the sub-Antarctic Indian Ocean. By sequencing a short region of this gene in 1492 pups from eight breeding colonies, we showed that S291F frequency rapidly declines with increasing geographical distance from South Georgia, consistent with locally restricted gene flow from South Georgia mainly to the South Shetland Islands and Bouvetøya. The S291F allele was not detected farther afield, suggesting that although emigrants from South Georgia may have been locally important, they are unlikely to have played a major role in the recovery of geographically more distant populations.
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Affiliation(s)
- J. I. Hoffman
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK
| | - E. Bauer
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - A. J. Paijmans
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - E. Humble
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - L. M. Beckmann
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - C. Kubetschek
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - F. Christaller
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - N. Kröcker
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - B. Fuchs
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - A. Moreras
- Department of Animal Behaviour, Bielefeld University, 33501 Bielefeld, Germany
| | - Y. D. Shihlomule
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - M. N. Bester
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - A. C. Cleary
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
| | - P. J. N. De Bruyn
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - J. Forcada
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK
| | - M. E. Goebel
- Antarctic Ecosystem Research Division, Southwest Fisheries Science Center, National Marine Fisheries, National Oceanographic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, CA 92037, USA
| | - S. D. Goldsworthy
- South Australian Research and Development Institute, 2 Hamra Avenue, West Beach, South Australia 5024, Australia
| | - C. Guinet
- Centre d'Etudes Biologiques de Chizé (CEBC), CNRS and Université de La Rochelle - UMR 7372, 79360 Villiers en Bois, France
| | - A. R. Hoelzel
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - C. Lydersen
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
| | - K. M. Kovacs
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
| | - A. Lowther
- Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway
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Luikart G, Kardos M, Hand BK, Rajora OP, Aitken SN, Hohenlohe PA. Population Genomics: Advancing Understanding of Nature. POPULATION GENOMICS 2018. [DOI: 10.1007/13836_2018_60] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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