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Interspecific hybridization contributes to high genetic diversity and apparent effective population size in an endemic population of mottled ducks (Anas fulvigula maculosa)

Conservation Genetics

By:
, , , , ,
DOI: 10.1007/s10592-013-0557-9

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Abstract

Under drift-mutation equilibrium, genetic diversity is expected to be correlated with effective population size (Ne). Changes in population size and gene flow are two important processes that can cause populations to deviate from this expected relationship. In this study, we used DNA sequences from six independent loci to examine the influence of these processes on standing genetic diversity in endemic mottled ducks (Anas fulvigula) and geographically widespread mallards (A. platyrhynchos), two species known to hybridize. Mottled ducks have an estimated census size that is about two orders-of-magnitude smaller than that of mallards, yet these two species have similar levels of genetic diversity, especially at nuclear DNA. Coalescent analyses suggest that a population expansion in the mallard at least partly explains this discrepancy, but the mottled duck harbors higher genetic diversity and apparent N e than expected for its census size even after accounting for a population decline. Incorporating gene flow into the model, however, reduced the estimated Ne of mottled ducks to 33 % of the equilibrium Ne and yielded an estimated Ne consistent with census size. We also examined the utility of these loci to distinguish among mallards, mottled ducks, and their hybrids. Most putatively pure individuals were correctly assigned to species, but the power for detecting hybrids was low. Although hybridization with mallards potentially poses a conservation threat to mottled ducks by creating a risk of extinction by hybridization, introgression of mallard alleles has helped maintain high genetic diversity in mottled ducks and might be important for the adaptability and survival of this species.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Interspecific hybridization contributes to high genetic diversity and apparent effective population size in an endemic population of mottled ducks (Anas fulvigula maculosa)
Series title:
Conservation Genetics
DOI:
10.1007/s10592-013-0557-9
Volume
15
Issue:
3
Year Published:
2014
Language:
English
Publisher:
Springer
Contributing office(s):
Alaska Science Center
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
509
Last page:
520
Number of Pages:
12