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1.
Mol Ecol Resour ; 22(7): 2546-2558, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35510790

RESUMO

Researchers have long debated which estimator of relatedness best captures the degree of relationship between two individuals. In the genomics era, this debate continues, with relatedness estimates being sensitive to the methods used to generate markers, marker quality, and levels of diversity in sampled individuals. Here, we compare six commonly used genome-based relatedness estimators (kinship genetic distance [KGD], Wang maximum likelihood [TrioML], Queller and Goodnight [Rxy ], Kinship INference for Genome-wide association studies [KING-robust), and pairwise relatedness [RAB ], allele-sharing coancestry [AS]) across five species bred in captivity-including three birds and two mammals-with varying degrees of reliable pedigree data, using reduced-representation and whole genome resequencing data. Genome-based relatedness estimates varied widely across estimators, sequencing methods, and species, yet the most consistent results for known first order relationships were found using Rxy , RAB , and AS. However, AS was found to be less consistently correlated with known pedigree relatedness than either Rxy or RAB . Our combined results indicate there is not a single genome-based estimator that is ideal across different species and data types. To determine the most appropriate genome-based relatedness estimator for each new data set, we recommend assessing the relative: (1) correlation of candidate estimators with known relationships in the pedigree and (2) precision of candidate estimators with known first-order relationships. These recommendations are broadly applicable to conservation breeding programmes, particularly where genome-based estimates of relatedness can complement and complete poorly pedigreed populations. Given a growing interest in the application of wild pedigrees, our results are also applicable to in situ wildlife management.


Assuntos
Cruzamento , Estudo de Associação Genômica Ampla , Alelos , Animais , Animais Selvagens , Humanos , Mamíferos , Modelos Genéticos , Linhagem
2.
Mol Ecol ; 31(1): 41-54, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34553796

RESUMO

Over the past 50 years conservation genetics has developed a substantive toolbox to inform species management. One of the most long-standing tools available to manage genetics-the pedigree-has been widely used to characterize diversity and maximize evolutionary potential in threatened populations. Now, with the ability to use high throughput sequencing to estimate relatedness, inbreeding, and genome-wide functional diversity, some have asked whether it is warranted for conservation biologists to continue collecting and collating pedigrees for species management. In this perspective, we argue that pedigrees remain a relevant tool, and when combined with genomic data, create an invaluable resource for conservation genomic management. Genomic data can address pedigree pitfalls (e.g., founder relatedness, missing data, uncertainty), and in return robust pedigrees allow for more nuanced research design, including well-informed sampling strategies and quantitative analyses (e.g., heritability, linkage) to better inform genomic inquiry. We further contend that building and maintaining pedigrees provides an opportunity to strengthen trusted relationships among conservation researchers, practitioners, Indigenous Peoples, and Local Communities.


Assuntos
Genética Populacional , Genômica , Conservação dos Recursos Naturais , Genoma , Endogamia , Linhagem
3.
Ecol Evol ; 11(22): 15800-15814, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34824791

RESUMO

Comparisons of microsatellites and single-nucleotide polymorphisms (SNPs) have found that SNPs outperform microsatellites in population genetic analyses, questioning the continued utility of microsatellites in population and landscape genetics. Yet, highly polymorphic markers may be of value in species that have reduced genetic variation. This study repeated previous analyses that used microsatellites with SNPs developed from ddRAD sequencing in the black-capped vireo source-sink system. SNPs provided greater resolution of genetic diversity, population differentiation, and migrant detection but could not reconstruct parentage relationships due to insufficient heterozygosities. The biological inferences made by both sets of markers were similar: asymmetrical gene flow from source sites to the remaining sink sites. With the landscape genetic analyses, we found different results between the two molecular markers, but associations of the top environmental features (riparian, open habitat, agriculture, and human development) with dispersal estimates were shared between marker types. Despite the higher precision of SNPs, we find that microsatellites effectively uncover population processes and patterns and are superior for parentage analyses in this species with reduced genetic diversity. This study illustrates the continued applicability and relevance of microsatellites in population genetic research.

4.
Ecol Evol ; 9(9): 5063-5078, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31110662

RESUMO

A critical decision in landscape genetic studies is whether to use individuals or populations as the sampling unit. This decision affects the time and cost of sampling and may affect ecological inference. We analyzed 334 Columbia spotted frogs at 8 microsatellite loci across 40 sites in northern Idaho to determine how inferences from landscape genetic analyses would vary with sampling design. At all sites, we compared a proportion available sampling scheme (PASS), in which all samples were used, to resampled datasets of 2-11 individuals. Additionally, we compared a population sampling scheme (PSS) to an individual sampling scheme (ISS) at 18 sites with sufficient sample size. We applied an information theoretic approach with both restricted maximum likelihood and maximum likelihood estimation to evaluate competing landscape resistance hypotheses. We found that PSS supported low-density forest when restricted maximum likelihood was used, but a combination model of most variables when maximum likelihood was used. We also saw variations when AIC was used compared to BIC. ISS supported this model as well as additional models when testing hypotheses of land cover types that create the greatest resistance to gene flow for Columbia spotted frogs. Increased sampling density and study extent, seen by comparing PSS to PASS, showed a change in model support. As number of individuals increased, model support converged at 7-9 individuals for ISS to PSS. ISS may be useful to increase study extent and sampling density, but may lack power to provide strong support for the correct model with microsatellite datasets. Our results highlight the importance of additional research on sampling design effects on landscape genetics inference.

5.
Ecol Evol ; 9(1): 463-470, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30680128

RESUMO

Habitat fragmentation can produce metapopulations or source-sink systems in which dispersal in crucial for population maintenance. Our objective was to investigate connectivity among black-capped vireo (Vireo atricapilla) populations in tandem with a demographic study (Biological Conservation, 2016, 203, 108-118) to elucidate if central Texas populations act as a source-sink system. We genotyped 343 individuals at 12 microsatellite loci to elucidate the movement ecology of the black-capped vireo in central Texas surrounding Fort Hood; the largest and most stable breeding population of black-capped vireos inhabit Fort Hood. To gain insight into gene flow among populations, we analyzed genetic differentiation, migration rates, number of migrants, and parentage. We found statistically significant, but low levels of genetic differentiation among several populations, suggesting some limited restriction to gene flow. Across approaches to estimate migration, we found consistent evidence for asymmetrical movement from Fort Hood to the other central Texas sites consistent with source-sink dynamics. Our results are complementary to black-capped vireo demographic studies done in tandem showing that portions of Fort Hood are acting as a source population to smaller central Texas populations.

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