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Fitzpatrick SW, Mittan-Moreau C, Miller M, Judson JM. Genetic rescue remains underused for aiding recovery of federally listed vertebrates in the United States. J Hered 2023; 114:354-366. [PMID: 36975379 PMCID: PMC10287150 DOI: 10.1093/jhered/esad002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 02/13/2023] [Indexed: 03/29/2023] Open
Abstract
Restoring gene flow among fragmented populations is discussed as a potentially powerful management strategy that could reduce inbreeding depression and cause genetic rescue. Yet, examples of assisted migration for genetic rescue remain sparse in conservation, prompting several outspoken calls for its increased use in genetic management of fragmented populations. We set out to evaluate the extent to which this strategy is underused and to determine how many imperiled species would realistically stand to benefit from genetic rescue, focusing on federally threatened or endangered vertebrate species in the United States. We developed a "genetic rescue suitability index (GR index)" based on concerns about small population problems relative to risks associated with outbreeding depression and surveyed the literature for 222 species. We found that two-thirds of these species were good candidates for consideration of assisted migration for the purpose of genetic rescue according to our suitability index. Good candidate species spanned all taxonomic groups and geographic regions, though species with more missing data tended to score lower on the suitability index. While we do not recommend a prescriptive interpretation of our GR index, we used it here to establish that assisted migration for genetic rescue is an underused strategy. For example, we found in total, "genetic rescue" was only mentioned in 11 recovery plans and has only been implemented in 3 of the species we surveyed. A potential way forward for implementation of this strategy is incorporating genetic rescue as a priority in USFWS recovery documentation. In general, our results suggest that although not appropriate for all imperiled species, many more species stand to benefit from a conservation strategy of assisted migration for genetic rescue than those for which it has previously been considered or implemented.
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Affiliation(s)
- Sarah W Fitzpatrick
- W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI, United States
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, United States
| | - Cinnamon Mittan-Moreau
- W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI, United States
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, United States
| | - Madison Miller
- Savannah River Ecology Lab, University of Georgia, Aiken, SC, United States
- Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV, United States
| | - Jessica M Judson
- W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI, United States
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, United States
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Li C, Xiao H, Zhang X, Lin H, Elmer KR, Zhao J. Deep genome-wide divergences among species in White Cloud Mountain minnow Tanichthys albonubes (Cypriniformes: Tanichthyidae) complex: Conservation and species management implications. Mol Phylogenet Evol 2023; 182:107734. [PMID: 36804428 DOI: 10.1016/j.ympev.2023.107734] [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: 09/08/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023]
Abstract
Identifying cryptic species is important for the assessments of biodiversity. Further, untangling mechanisms underlying the origins of cryptic species can facilitate our understanding of evolutionary processes. Advancements in genomic approaches for non-model systems have offered unprecedented opportunities to investigate these areas. The White Cloud Mountain minnow (Tanichthys albonubes) is a popular freshwater pet fish worldwide but its wild populations in China are critically endangered. Recent research based on a few molecular markers suggested that this species in fact comprised seven cryptic species, of which six were previously unknown. Here, we tested six of these cryptic species and quantified genomic interspecific divergences between species in the T. albonubes complex by analyzing genome-wide restriction site-associated DNA sequencing (RADseq) data generated from 189 individuals sampled from seven populations (including an outgroup congeneric species, T. micagemmae). We found that six cryptic species previously suggested were well supported by RADseq data. The genetic diversity of each species in the T. albonubes complex was low compared with T. micagemmae and the contemporary effective population sizes (Ne) of each cryptic species were small. Phylogenetic analysis showed seven clades with high support values confirmed with Neighbor-Net trees. The pairwise divergences between species in T. albonubes complex were deep and the highly differentiated loci were evenly distributed across the genome. We proposed that the divergence level of T. albonubes complex is at a late stage of cryptic speciation and lacking gene flow. Our findings provide new insights into cryptic speciation and have important implications for conservation and species management of T. albonubes complex.
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Affiliation(s)
- Chao Li
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China; Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Han Xiao
- Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
| | - Xiuxia Zhang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Hungdu Lin
- The Affiliated School of National Tainan First Senior High School, Tainan, Taiwan
| | - Kathryn R Elmer
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jun Zhao
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China.
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Feng L, Du FK. Landscape Genomics in Tree Conservation Under a Changing Environment. FRONTIERS IN PLANT SCIENCE 2022; 13:822217. [PMID: 35283901 PMCID: PMC8908315 DOI: 10.3389/fpls.2022.822217] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/10/2022] [Indexed: 05/11/2023]
Abstract
Understanding the genetic basis of how species respond to changing environments is essential to the conservation of species. However, the molecular mechanisms of adaptation remain largely unknown for long-lived tree species which always have large population sizes, long generation time, and extensive gene flow. Recent advances in landscape genomics can reveal the signals of adaptive selection linking genetic variations and landscape characteristics and therefore have created novel insights into tree conservation strategies. In this review article, we first summarized the methods of landscape genomics used in tree conservation and elucidated the advantages and disadvantages of these methods. We then highlighted the newly developed method "Risk of Non-adaptedness," which can predict the genetic offset or genomic vulnerability of species via allele frequency change under multiple scenarios of climate change. Finally, we provided prospects concerning how our introduced approaches of landscape genomics can assist policymaking and improve the existing conservation strategies for tree species under the ongoing global changes.
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Affiliation(s)
- Li Feng
- School of Pharmacy, Xi’an Jiaotong University, Xi’an, China
| | - Fang K. Du
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
- *Correspondence: Fang K. Du,
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Bemmels JB, Mikkelsen EK, Haddrath O, Colbourne RM, Robertson HA, Weir JT. Demographic decline and lineage-specific adaptations characterize New Zealand kiwi. Proc Biol Sci 2021; 288:20212362. [PMID: 34905706 PMCID: PMC8670953 DOI: 10.1098/rspb.2021.2362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/19/2021] [Indexed: 12/24/2022] Open
Abstract
Small and fragmented populations may become rapidly differentiated due to genetic drift, making it difficult to distinguish whether neutral genetic structure is a signature of recent demographic events, or of long-term evolutionary processes that could have allowed populations to adaptively diverge. We sequenced 52 whole genomes to examine Holocene demographic history and patterns of adaptation in kiwi (Apteryx), and recovered 11 strongly differentiated genetic clusters corresponding to previously recognized lineages. Demographic models suggest that all 11 lineages experienced dramatic population crashes relative to early- or mid-Holocene levels. Small population size is associated with low genetic diversity and elevated genetic differentiation (FST), suggesting that population declines have strengthened genetic structure and led to the loss of genetic diversity. However, population size is not correlated with inbreeding rates. Eight lineages show signatures of lineage-specific selective sweeps (284 sweeps total) that are unlikely to have been caused by demographic stochasticity. Overall, these results suggest that despite strong genetic drift associated with recent bottlenecks, most kiwi lineages possess unique adaptations and should be recognized as separate adaptive units in conservation contexts. Our work highlights how whole-genome datasets can address longstanding uncertainty about the evolutionary and conservation significance of small and fragmented populations of threatened species.
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Affiliation(s)
- Jordan B. Bemmels
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada ON M1C 1A4
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada ON M5S 3B2
| | - Else K. Mikkelsen
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada ON M1C 1A4
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada ON M5S 3B2
| | - Oliver Haddrath
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada ON M5S 3B2
- Department of Natural History, Royal Ontario Museum, Toronto, Canada ON M5S 2C6
| | | | | | - Jason T. Weir
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada ON M1C 1A4
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada ON M5S 3B2
- Department of Natural History, Royal Ontario Museum, Toronto, Canada ON M5S 2C6
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New developments in the field of genomic technologies and their relevance to conservation management. CONSERV GENET 2021. [DOI: 10.1007/s10592-021-01415-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AbstractRecent technological advances in the field of genomics offer conservation managers and practitioners new tools to explore for conservation applications. Many of these tools are well developed and used by other life science fields, while others are still in development. Considering these technological possibilities, choosing the right tool(s) from the toolbox is crucial and can pose a challenging task. With this in mind, we strive to inspire, inform and illuminate managers and practitioners on how conservation efforts can benefit from the current genomic and biotechnological revolution. With inspirational case studies we show how new technologies can help resolve some of the main conservation challenges, while also informing how implementable the different technologies are. We here focus specifically on small population management, highlight the potential for genetic rescue, and discuss the opportunities in the field of gene editing to help with adaptation to changing environments. In addition, we delineate potential applications of gene drives for controlling invasive species. We illuminate that the genomic toolbox offers added benefit to conservation efforts, but also comes with limitations for the use of these novel emerging techniques.
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Genomic Approaches for Conservation Management in Australia under Climate Change. Life (Basel) 2021; 11:life11070653. [PMID: 34357024 PMCID: PMC8304512 DOI: 10.3390/life11070653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 12/28/2022] Open
Abstract
Conservation genetics has informed threatened species management for several decades. With the advent of advanced DNA sequencing technologies in recent years, it is now possible to monitor and manage threatened populations with even greater precision. Climate change presents a number of threats and challenges, but new genomics data and analytical approaches provide opportunities to identify critical evolutionary processes of relevance to genetic management under climate change. Here, we discuss the applications of such approaches for threatened species management in Australia in the context of climate change, identifying methods of facilitating viability and resilience in the face of extreme environmental stress. Using genomic approaches, conservation management practices such as translocation, targeted gene flow, and gene-editing can now be performed with the express intention of facilitating adaptation to current and projected climate change scenarios in vulnerable species, thus reducing extinction risk and ensuring the protection of our unique biodiversity for future generations. We discuss the current barriers to implementing conservation genomic projects and the efforts being made to overcome them, including communication between researchers and managers to improve the relevance and applicability of genomic studies. We present novel approaches for facilitating adaptive capacity and accelerating natural selection in species to encourage resilience in the face of climate change.
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Fitzpatrick SW, Bradburd GS, Kremer CT, Salerno PE, Angeloni LM, Funk WC. Genomic and Fitness Consequences of Genetic Rescue in Wild Populations. Curr Biol 2020; 30:517-522.e5. [PMID: 31902732 DOI: 10.1016/j.cub.2019.11.062] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/11/2019] [Accepted: 11/20/2019] [Indexed: 10/25/2022]
Abstract
Gene flow is an enigmatic evolutionary force because it can limit adaptation but may also rescue small populations from inbreeding depression [1-3]. Several iconic examples of genetic rescue-increased population growth caused by gene flow [4, 5]-have reversed population declines [6, 7]. However, concerns about outbreeding depression and maladaptive gene flow limit the use of human-mediated gene flow in conservation [8, 9]. Rescue effects of immigration through demographic and/or genetic mechanisms have received theoretical and empirical support, but studies that monitor initial and long-term effects of gene flow on individuals and populations in the wild are lacking. Here, we used individual-based mark-recapture, multigenerational pedigrees, and genomics to test the demographic and evolutionary consequences of manipulating gene flow in two isolated, wild Trinidadian guppy populations. Recipient and source populations originated from environments with different predation, flow, and resource regimes [10]. We documented 10-fold increases in population size following gene flow and found that, on average, hybrids lived longer and reproduced more than residents and immigrants. Despite overall genomic homogenization, alleles potentially associated with local adaptation were not entirely swamped by gene flow. Our results suggest that genetic rescue was caused not just by increasing individual genetic diversity, rather new genomic variation from immigrants combined with alleles from the recipient population resulted in highly fit hybrids and subsequent increases in population size. Contrary to the classic view of maladaptive gene flow, our study reveals conditions under which immigration can produce long-term fitness benefits in small populations without entirely swamping adaptive variation.
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Affiliation(s)
- Sarah W Fitzpatrick
- W.K. Kellogg Biological Station, Michigan State University, 3700 E. Gull Lake Drive, Hickory Corners, MI 49060, USA; Department of Integrative Biology, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA; Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA.
| | - Gideon S Bradburd
- Department of Integrative Biology, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA; Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Colin T Kremer
- W.K. Kellogg Biological Station, Michigan State University, 3700 E. Gull Lake Drive, Hickory Corners, MI 49060, USA
| | - Patricia E Salerno
- Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA; Universidad Regional Amazónica Ikiam, Km 7 Vía Muyuna, Tena, Napo, Ecuador
| | - Lisa M Angeloni
- Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA; Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523, USA
| | - W Chris Funk
- Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA; Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523, USA
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Bell DA, Robinson ZL, Funk WC, Fitzpatrick SW, Allendorf FW, Tallmon DA, Whiteley AR. The Exciting Potential and Remaining Uncertainties of Genetic Rescue. Trends Ecol Evol 2019; 34:1070-1079. [PMID: 31296345 DOI: 10.1016/j.tree.2019.06.006] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 02/03/2023]
Abstract
Restoring gene flow into small, isolated populations can alleviate genetic load and decrease extinction risk (i.e., genetic rescue), yet gene flow is rarely augmented as a conservation strategy. Due to this discrepancy between opportunity and action, a recent call was made for widespread genetic rescue attempts. However, several aspects of augmenting gene flow are poorly understood, including the magnitude and duration of beneficial effects and when deleterious effects are likely to occur. We discuss the remaining uncertainties of genetic rescue in order to promote and direct future research and to hasten progress toward implementing this potentially powerful conservation strategy on a broader scale.
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Affiliation(s)
- Donovan A Bell
- Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA.
| | - Zachary L Robinson
- Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
| | - W Chris Funk
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA
| | - Sarah W Fitzpatrick
- W.K. Kellogg Biological Station, Department of Integrative Biology, Michigan State University, Hickory Corners, MI, USA; Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI, USA
| | - Fred W Allendorf
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - David A Tallmon
- Biology and Marine Biology Program, University of Alaska Southeast, Juneau, AK, USA
| | - Andrew R Whiteley
- Wildlife Biology Program, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, MT, USA
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