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Cavill EL, Morales HE, Sun X, Westbury MV, van Oosterhout C, Accouche W, Zora A, Schulze MJ, Shah N, Adam P, Brooke MDL, Sweet P, Gopalakrishnan S, Gilbert MTP. When birds of a feather flock together: Severe genomic erosion and the implications for genetic rescue in an endangered island passerine. Evol Appl 2024; 17:e13739. [PMID: 38948538 PMCID: PMC11212007 DOI: 10.1111/eva.13739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 05/22/2024] [Accepted: 06/04/2024] [Indexed: 07/02/2024] Open
Abstract
The Seychelles magpie-robin's (SMR) five island populations exhibit some of the lowest recorded levels of genetic diversity among endangered birds, and high levels of inbreeding. These populations collapsed during the 20th century, and the species was listed as Critically Endangered in the IUCN Red List in 1994. An assisted translocation-for-recovery program initiated in the 1990s increased the number of mature individuals, resulting in its downlisting to Endangered in 2005. Here, we explore the temporal genomic erosion of the SMR based on a dataset of 201 re-sequenced whole genomes that span the past ~150 years. Our sample set includes individuals that predate the bottleneck by up to 100 years, as well as individuals from contemporary populations established during the species recovery program. Despite the SMR's recent demographic recovery, our data reveal a marked increase in both the genetic load and realized load in the extant populations when compared to the historical samples. Conservation management may have reduced the intensity of selection by increasing juvenile survival and relaxing intraspecific competition between individuals, resulting in the accumulation of loss-of-function mutations (i.e. severely deleterious variants) in the rapidly recovering population. In addition, we found a 3-fold decrease in genetic diversity between temporal samples. While the low genetic diversity in modern populations may limit the species' adaptability to future environmental changes, future conservation efforts (including IUCN assessments) may also need to assess the threats posed by their high genetic load. Our computer simulations highlight the value of translocations for genetic rescue and show how this could halt genomic erosion in threatened species such as the SMR.
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Affiliation(s)
- Emily L. Cavill
- The Globe Institute, University of CopenhagenCopenhagenDenmark
| | | | - Xin Sun
- The Globe Institute, University of CopenhagenCopenhagenDenmark
| | | | - Cock van Oosterhout
- School of Environmental SciencesUniversity of East Anglia, Norwich Research ParkNorwichUK
| | | | - Anna Zora
- Fregate Island Sanctuary LtdVictoriaSeychelles
| | | | | | | | | | - Paul Sweet
- American Museum of Natural HistoryNew YorkUSA
| | | | - M. Thomas P. Gilbert
- The Globe Institute, University of CopenhagenCopenhagenDenmark
- University Museum, Norwegian University of Science and TechnologyTrondheimNorway
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Atağ G, Kaptan D, Yüncü E, Başak Vural K, Mereu P, Pirastru M, Barbato M, Leoni GG, Güler MN, Er T, Eker E, Yazıcı TD, Kılıç MS, Altınışık NE, Çelik EA, Morell Miranda P, Dehasque M, Floridia V, Götherström A, Bilgin CC, Togan İ, Günther T, Özer F, Hadjisterkotis E, Somel M. Population Genomic History of the Endangered Anatolian and Cyprian Mouflons in Relation to Worldwide Wild, Feral, and Domestic Sheep Lineages. Genome Biol Evol 2024; 16:evae090. [PMID: 38670119 PMCID: PMC11109821 DOI: 10.1093/gbe/evae090] [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: 01/15/2024] [Revised: 04/09/2024] [Accepted: 04/22/2024] [Indexed: 04/28/2024] Open
Abstract
Once widespread in their homelands, the Anatolian mouflon (Ovis gmelini anatolica) and the Cyprian mouflon (Ovis gmelini ophion) were driven to near extinction during the 20th century and are currently listed as endangered populations by the International Union for Conservation of Nature. While the exact origins of these lineages remain unclear, they have been suggested to be close relatives of domestic sheep or remnants of proto-domestic sheep. Here, we study whole genome sequences of n = 5 Anatolian mouflons and n = 10 Cyprian mouflons in terms of population history and diversity, comparing them with eight other extant sheep lineages. We find reciprocal genetic affinity between Anatolian and Cyprian mouflons and domestic sheep, higher than all other studied wild sheep genomes, including the Iranian mouflon (O. gmelini). Studying diversity indices, we detect a considerable load of short runs of homozygosity blocks (<2 Mb) in both Anatolian and Cyprian mouflons, reflecting small effective population size (Ne). Meanwhile, Ne and mutation load estimates are lower in Cyprian compared with Anatolian mouflons, suggesting the purging of recessive deleterious variants in Cyprian sheep under a small long-term Ne, possibly attributable to founder effects, island isolation, introgression from domestic lineages, or differences in their bottleneck dynamics. Expanding our analyses to worldwide wild and feral Ovis genomes, we observe varying viability metrics among different lineages and a limited consistency between viability metrics and International Union for Conservation of Nature conservation status. Factors such as recent inbreeding, introgression, and unique population dynamics may have contributed to the observed disparities.
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Affiliation(s)
- Gözde Atağ
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Damla Kaptan
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Eren Yüncü
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Kıvılcım Başak Vural
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Paolo Mereu
- Department of Biochemical Sciences, University of Sassari, Sassari, Italy
| | - Monica Pirastru
- Department of Biochemical Sciences, University of Sassari, Sassari, Italy
| | - Mario Barbato
- Department of Veterinary Sciences, University of Messina, Messina, Italy
| | | | - Merve Nur Güler
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | - Tuğçe Er
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Elifnaz Eker
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Tunca Deniz Yazıcı
- Graduate School for Evolution, Ecology and Systematics, Ludwig Maximillian University of Munich, Munich, Germany
| | - Muhammed Sıddık Kılıç
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | | | - Ecem Ayşe Çelik
- Department of Settlement Archeology, Middle East Technical University, Ankara, Turkey
| | - Pedro Morell Miranda
- Human Evolution, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | - Marianne Dehasque
- Human Evolution, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | - Viviana Floridia
- Department of Veterinary Sciences, University of Messina, Messina, Italy
| | - Anders Götherström
- Department of Archaeology and Classical Studies, Stockholm University, Stockholm, Sweden
- Centre for Palaeogenetics, Stockholm University, Stockholm, Sweden
| | - Cemal Can Bilgin
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - İnci Togan
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
| | - Torsten Günther
- Human Evolution, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | - Füsun Özer
- Department of Anthropology, Hacettepe University, Ankara, Turkey
| | - Eleftherios Hadjisterkotis
- Agricultural Research Institute, Ministry of Agriculture, Rural Development and Environment, Nicosia, Cyprus
| | - Mehmet Somel
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey
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Hogg CJ. Translating genomic advances into biodiversity conservation. Nat Rev Genet 2024; 25:362-373. [PMID: 38012268 DOI: 10.1038/s41576-023-00671-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2023] [Indexed: 11/29/2023]
Abstract
A key action of the new Global Biodiversity Framework is the maintenance of genetic diversity in all species to safeguard their adaptive potential. To achieve this goal, a translational mindset, which aims to convert results of basic research into direct practical benefits, needs to be applied to biodiversity conservation. Despite much discussion on the value of genomics to conservation, a disconnect between those generating genomic resources and those applying it to biodiversity management remains. As global efforts to generate reference genomes for non-model species increase, investment into practical biodiversity applications is critically important. Applications such as understanding population and multispecies diversity and longitudinal monitoring need support alongside education for policymakers on integrating the data into evidence-based decisions. Without such investment, the opportunity to revolutionize global biodiversity conservation using genomics will not be fully realized.
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Affiliation(s)
- Carolyn J Hogg
- School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW, Australia.
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Lawson DJ, Howard-McCombe J, Beaumont M, Senn H. How admixed captive breeding populations could be rescued using local ancestry information. Mol Ecol 2024:e17349. [PMID: 38634332 DOI: 10.1111/mec.17349] [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: 09/14/2023] [Revised: 12/21/2023] [Accepted: 02/26/2024] [Indexed: 04/19/2024]
Abstract
This paper asks the question: can genomic information be used to recover a species that is already on the pathway to extinction due to genetic swamping from a related and more numerous population? We show that a breeding strategy in a captive breeding program can use whole genome sequencing to identify and remove segments of DNA introgressed through hybridisation. The proposed policy uses a generalized measure of kinship or heterozygosity accounting for local ancestry, that is, whether a specific genetic location was inherited from the target of conservation. We then show that optimizing these measures would minimize undesired ancestry while also controlling kinship and/or heterozygosity, in a simulated breeding population. The process is applied to real data representing the hybridized Scottish wildcat breeding population, with the result that it should be possible to breed out domestic cat ancestry. The ability to reverse introgression is a powerful tool brought about through the combination of sequencing with computational advances in ancestry estimation. Since it works best when applied early in the process, important decisions need to be made about which genetically distinct populations should benefit from it and which should be left to reform into a single population.
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Affiliation(s)
- Daniel J Lawson
- Institute of Statistical Sciences, School of Mathematics, University of Bristol, Bristol, UK
| | - Jo Howard-McCombe
- RZSS WildGenes Laboratory, Conservation Department, Royal Zoological Society of Scotland, Edinburgh, UK
| | - Mark Beaumont
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Helen Senn
- RZSS WildGenes Laboratory, Conservation Department, Royal Zoological Society of Scotland, Edinburgh, UK
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Smeds L, Huson LSA, Ellegren H. Structural genomic variation in the inbred Scandinavian wolf population contributes to the realized genetic load but is positively affected by immigration. Evol Appl 2024; 17:e13652. [PMID: 38333557 PMCID: PMC10848878 DOI: 10.1111/eva.13652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/08/2024] [Accepted: 01/16/2024] [Indexed: 02/10/2024] Open
Abstract
When populations decrease in size and may become isolated, genomic erosion by loss of diversity from genetic drift and accumulation of deleterious mutations is likely an inevitable consequence. In such cases, immigration (genetic rescue) is necessary to restore levels of genetic diversity and counteract inbreeding depression. Recent work in conservation genomics has studied these processes focusing on the genetic diversity of single nucleotide polymorphisms. In contrast, our knowledge about structural genomic variation (insertions, deletions, duplications and inversions) in endangered species is limited. We analysed whole-genome, short-read sequences from 212 wolves from the inbred Scandinavian population and from neighbouring populations in Finland and Russia, and detected >35,000 structural variants (SVs) after stringent quality and genotype frequency filtering; >26,000 high-confidence variants remained after manual curation. The majority of variants were shorter than 1 kb, with a distinct peak in the length distribution of deletions at 190 bp, corresponding to insertion events of SINE/tRNA-Lys elements. The site frequency spectrum of SVs in protein-coding regions was significantly shifted towards rare alleles compared to putatively neutral variants, consistent with purifying selection. The realized genetic load of SVs in protein-coding regions increased with inbreeding levels in the Scandinavian population, but immigration provided a genetic rescue effect by lowering the load and reintroducing ancestral alleles at loci fixed for derived SVs. Our study shows that structural variation comprises a common type of in part deleterious mutations in endangered species and that establishing gene flow is necessary to mitigate the negative consequences of loss of diversity.
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Affiliation(s)
- Linnéa Smeds
- Department of Ecology and Genetics, Evolutionary BiologyUppsala UniversityUppsalaSweden
| | - Lars S. A. Huson
- Department of Ecology and Genetics, Evolutionary BiologyUppsala UniversityUppsalaSweden
| | - Hans Ellegren
- Department of Ecology and Genetics, Evolutionary BiologyUppsala UniversityUppsalaSweden
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De León LF, Silva B, Avilés-Rodríguez KJ, Buitrago-Rosas D. Harnessing the omics revolution to address the global biodiversity crisis. Curr Opin Biotechnol 2023; 80:102901. [PMID: 36773576 DOI: 10.1016/j.copbio.2023.102901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/10/2023] [Accepted: 01/18/2023] [Indexed: 02/12/2023]
Abstract
Human disturbances are altering global biodiversity in unprecedented ways. We identify three fundamental challenges underpinning our understanding of global biodiversity (namely discovery, loss, and preservation), and discuss how the omics revolution (e.g. genomics, transcriptomics, proteomics, metabolomics, and meta-omics) can help address these challenges. We also discuss how omics tools can illuminate the major drivers of biodiversity loss, including invasive species, pollution, urbanization, overexploitation, and climate change, with a special focus on highly diverse tropical environments. Although omics tools are transforming the traditional toolkit of biodiversity research, their application to addressing the current biodiversity crisis remains limited and may not suffice to offset current rates of biodiversity loss. Despite technical and logistical challenges, omics tools need to be fully integrated into global biodiversity research, and better strategies are needed to improve their translation into biodiversity policy and practice. It is also important to recognize that although the omics revolution can be considered the biologist's dream, socioeconomic disparity limits their application in biodiversity research.
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Affiliation(s)
- Luis F De León
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA.
| | - Bruna Silva
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Kevin J Avilés-Rodríguez
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA; Department of Biology, Fordham University, Bronx, NY, USA
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