Quantitative genetics in conservation biology

Most of the major genetic concerns in conservation biology, including inbreeding depression, loss of evolutionary potential, genetic adaptation to captivity and outbreeding depression, involve quantitative genetics. Small population size leads to inbreeding and loss of genetic diversity and so increases extinction risk. Captive populations of endangered species are managed to maximize the retention of genetic diversity by minimizing kinship, with subsidiary efforts to minimize inbreeding. There is growing evidence that genetic adaptation to captivity is a major issue in the genetic management of captive populations of endangered species as it reduces reproductive fitness when captive populations are reintroduced into the wild. This problem is not currently addressed, but it can be alleviated by deliberately fragmenting captive populations, with occasional exchange of immigrants to avoid excessive inbreeding. The extent and importance of outbreeding depression is a matter of controversy. Currently, an extremely cautious approach is taken to mixing populations. However, this cannot continue if fragmented populations are to be adequately managed to minimize extinctions. Most genetic management recommendations for endangered species arise directly, or indirectly, from quantitative genetic considerations.

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Genetic Management of Fragmented Animal and Plant Populations

10.1093/oso/9780198783398.001.0001 ◽

2017 ◽

Cited By ~ 103

Author(s):

Richard Frankham ◽

Jonathan D. Ballou ◽

Katherine Ralls ◽

Mark Eldridge ◽

Michele R. Dudash ◽

...

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Biological Diversity ◽

Extinction Risk ◽

Outbreeding Depression ◽

Genetic Rescue ◽

Isolated Populations ◽

Genetic Management ◽

Plant Populations ◽

Loss Of Genetic Diversity

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable consequences for many species. Many small isolated populations are going extinct unnecessarily. In many cases, such populations can be genetically rescued by gene flow into them from another population within the species, but this is very rarely done. This novel and authoritative book addresses the issues involved in genetic management of fragmented animal and plant populations, including inbreeding depression, loss of genetic diversity and elevated extinction risk in small isolated populations, augmentation of gene flow, genetic rescue, causes of outbreeding depression and predicting its occurrence, desirability and implementation of genetic translocations to cope with climate change, and defining and diagnosing species for conservation purposes.

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Diploid male production correlates with genetic diversity in the parasitoid wasp Venturia canescens: a genetic approach with new microsatellite markers

10.1101/054866 ◽

2016 ◽

Author(s):

Marie Collet ◽

Chloé Vayssade ◽

Alexandra Auguste ◽

Laurence Mouton ◽

Emmanuel Desouhant ◽

...

Keyword(s):

Genetic Diversity ◽

Sex Determination ◽

Extinction Risk ◽

Habitat Type ◽

Parasitoid Wasp ◽

Habitat Destruction ◽

Diploid Male ◽

Diploid Males ◽

Venturia Canescens ◽

Captive Populations

AbstractSex determination is ruled by haplodiploidy in Hymenoptera, with haploid males arising from unfertilized eggs and diploid females from fertilized eggs. However, diploid males with null fitness are produced under Complementary Sex Determination (CSD), whenindividuals are homozygous for this locus. Diploid males are expected to be more frequent in genetically eroded populations (such as islands and captive populations), as genetic diversity at the csd locus should be low. However, only a few studies have focused on the relation between population size, genetic diversity and the proportion of diploid males in the field. Here, we developed new microsatellites markers in order to assess and compare genetic diversity and diploid male proportion in populations from three distinct habitat types (mainland, island or captive), in the parasitoid wasp Venturia canescens. Eroded genetic diversity and higher diploid male proportion were found in island and captive populations, and habitat type had large effect on genetic diversity. Therefore, diploid male proportion reflects the decreasing genetic diversity in small and isolated populations. Thus, Hymenopteran populations can be at high extinction risk due to habitat destruction or fragmentation.

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Reducing the Extinction Risk of Populations Threatened by Infectious Diseases

Diversity ◽

10.3390/d13020063 ◽

2021 ◽

Vol 13 (2) ◽

pp. 63

Author(s):

Gael L. Glassock ◽

Catherine E. Grueber ◽

Katherine Belov ◽

Carolyn J. Hogg

Keyword(s):

Gene Flow ◽

Infectious Diseases ◽

Extinction Risk ◽

Population Decline ◽

Outbreeding Depression ◽

Tasmanian Devil ◽

Adaptive Potential ◽

Genetic Management ◽

Animal Populations ◽

Devil Facial Tumour Disease

Extinction risk is increasing for a range of species due to a variety of threats, including disease. Emerging infectious diseases can cause severe declines in wild animal populations, increasing population fragmentation and reducing gene flow. Small, isolated, host populations may lose adaptive potential and become more susceptible to extinction due to other threats. Management of the genetic consequences of disease-induced population decline is often necessary. Whilst disease threats need to be addressed, they can be difficult to mitigate. Actions implemented to conserve the Tasmanian devil (Sarcophilus harrisii), which has suffered decline to the deadly devil facial tumour disease (DFTD), exemplify how genetic management can be used to reduce extinction risk in populations threatened by disease. Supplementation is an emerging conservation technique that may benefit populations threatened by disease by enabling gene flow and conserving their adaptive potential through genetic restoration. Other candidate species may benefit from genetic management via supplementation but concerns regarding outbreeding depression may prevent widespread incorporation of this technique into wildlife disease management. However, existing knowledge can be used to identify populations that would benefit from supplementation where risk of outbreeding depression is low. For populations threatened by disease and, in situations where disease eradication is not an option, wildlife managers should consider genetic management to buffer the host species against inbreeding and loss of genetic diversity.

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Integrating Genomic Data Sets for Knowledge Discovery: An Informed Approach to Management of Captive Endangered Species

International Journal of Genomics ◽

10.1155/2016/2374610 ◽

2016 ◽

Vol 2016 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Kristopher J. L. Irizarry ◽

Doug Bryant ◽

Jordan Kalish ◽

Curtis Eng ◽

Peggy L. Schmidt ◽

...

Keyword(s):

Genetic Diversity ◽

Endangered Species ◽

Sequence Data ◽

Genomic Data ◽

Cost Effective ◽

Model Organisms ◽

Data Sets ◽

Captive Populations ◽

Species Survival ◽

Population Genetic Variation

Many endangered captive populations exhibit reduced genetic diversity resulting in health issues that impact reproductive fitness and quality of life. Numerous cost effective genomic sequencing and genotyping technologies provide unparalleled opportunity for incorporating genomics knowledge in management of endangered species. Genomic data, such as sequence data, transcriptome data, and genotyping data, provide critical information about a captive population that, when leveraged correctly, can be utilized to maximize population genetic variation while simultaneously reducing unintended introduction or propagation of undesirable phenotypes. Current approaches aimed at managing endangered captive populations utilize species survival plans (SSPs) that rely upon mean kinship estimates to maximize genetic diversity while simultaneously avoiding artificial selection in the breeding program. However, as genomic resources increase for each endangered species, the potential knowledge available for management also increases. Unlike model organisms in which considerable scientific resources are used to experimentally validate genotype-phenotype relationships, endangered species typically lack the necessary sample sizes and economic resources required for such studies. Even so, in the absence of experimentally verified genetic discoveries, genomics data still provides value. In fact, bioinformatics and comparative genomics approaches offer mechanisms for translating these raw genomics data sets into integrated knowledge that enable an informed approach to endangered species management.

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Genetic Diversity and Population Structure of Two Endangered Neotropical Parrots Inform In Situ and Ex Situ Conservation Strategies

Diversity ◽

10.3390/d13080386 ◽

2021 ◽

Vol 13 (8) ◽

pp. 386

Author(s):

Carlos I. Campos ◽

Melinda A. Martinez ◽

Daniel Acosta ◽

Jose A. Diaz-Luque ◽

Igor Berkunsky ◽

...

Keyword(s):

Genetic Diversity ◽

Genetic Variation ◽

Management Strategies ◽

Ex Situ ◽

Conservation Strategies ◽

Genetic Management ◽

Captive Populations ◽

In Captivity ◽

In The Wild ◽

Genetic Signatures

A key aspect in the conservation of endangered populations is understanding patterns of genetic variation and structure, which can provide managers with critical information to support evidence-based status assessments and management strategies. This is especially important for species with small wild and larger captive populations, as found in many endangered parrots. We used genotypic data to assess genetic variation and structure in wild and captive populations of two endangered parrots, the blue-throated macaw, Ara glaucogularis, of Bolivia, and the thick-billed parrot, Rhynchopsitta pachyrhyncha, of Mexico. In the blue-throated macaw, we found evidence of weak genetic differentiation between wild northern and southern subpopulations, and between wild and captive populations. In the thick-billed parrot we found no signal of differentiation between the Madera and Tutuaca breeding colonies or between wild and captive populations. Similar levels of genetic diversity were detected in the wild and captive populations of both species, with private alleles detected in captivity in both, and in the wild in the thick-billed parrot. We found genetic signatures of a bottleneck in the northern blue-throated macaw subpopulation, but no such signal was identified in any other subpopulation of either species. Our results suggest both species could potentially benefit from reintroduction of genetic variation found in captivity, and emphasize the need for genetic management of captive populations.

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Introduction

A Practical Guide for Genetic Management of Fragmented Animal and Plant Populations ◽

10.1093/oso/9780198783411.003.0001 ◽

2019 ◽

pp. 1-12

Author(s):

Richard Frankham ◽

Jonathan D. Ballou ◽

Katherine Ralls ◽

Mark D. B. Eldridge ◽

Michele R. Dudash ◽

...

Keyword(s):

Climate Change ◽

Genetic Diversity ◽

Gene Flow ◽

Global Climate Change ◽

Global Climate ◽

Extinction Risk ◽

Genetic Erosion ◽

Isolated Populations ◽

Genetic Management ◽

Loss Of Genetic Diversity

Genetic management of fragmented populations is one of the major, largely unaddressed issues in biodiversity conservation. Many species across the planet have fragmented distributions with small isolated populations that are potentially suffering from inbreeding and loss of genetic diversity (genetic erosion), leading to elevated extinction risk. Fortunately, genetic deterioration can usually be remedied by gene flow from another population (crossing between populations within species), yet this is rarely done, in part because of fears that crossing may be harmful (but we can predict when this will occur). We address management of gene flow between previously isolated populations and genetic management under global climate change.

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Initial approach to the Conservation Genetics of the Guatemalan Beaded Lizard (Heloderma charlesbogerti): A route to genetic rescue

10.1101/2021.11.02.466675 ◽

2021 ◽

Author(s):

Sergio A Gonzalez-Mollinedo ◽

Thomas Schrei ◽

Brad Locke

Keyword(s):

Genetic Diversity ◽

Population Size ◽

Effective Population Size ◽

Extinction Risk ◽

Genetic Erosion ◽

Unknown Origin ◽

Single Individual ◽

Effective Population ◽

Genetic Management ◽

Low Genetic Diversity

In this study, samples from 33 Guatemalan Beaded Lizard (Heloderma charlesbogerti) were analyzed for genetic diversity. Twenty-three samples were obtained from wild individuals from two separate population areas, and 10 samples were obtained from captive individuals. Because the seasonally dry tropical forest habitat sampled for this study, is degraded and fragmented, it was hypothesized that beaded lizard populations were small and isolated and would be subject to genetic erosion and an elevated extinction risk. To test this hypothesis, eight microsatellite markers were employed to analyze 22 individual samples from the population of Cabanas, Zacapa, a single individual from the eastern-most population and 10 captive individuals of unknown origin. An average of three alleles per maker was reported for the Cabanas population, evidencing a low genetic diversity. In addition, a recent bottleneck event was detected and an effective population size of 19.6 was estimated. Demographic reconstruction using a Bayesian approach was inconclusive possibly due to a small dataset and shallow coalescence trees obtained with the generated data. No clear structuring pattern was detected for the Cabanas population and most samples from individuals in captivity were found to have similar alleles to the ones from Cabanas. Population designation is challenging without the genotyping of every wild population, but unique alleles were found in captive individuals of unknown origin that could suggest that different genotypes might exist within other, less studied, wild populations. Low genetic diversity, and a small effective population size represent a risk for the Cabanas population facing the threats of isolation, habitat loss and climate change. These findings suggest that genetic management of the Cabanas population might be utilized to avoid high rates of inbreeding and subsequent inbreeding depression.

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