Population genetic structure and disease in montane boreal toads: More heterozygous individuals are more likely to be infected with amphibian chytrid

Conservation Genetics
By: , and 

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Abstract

Amphibians are more threatened than any other vertebrate group, with 41 % of species classified as threatened. The causes of most declines are not well understood, though many declines have been linked to disease. Additionally, amphibians are physiologically constrained to moist habitats and considered poor dispersers; thus, they may suffer genetic consequences of population isolation. To understand threats to the persistence of boreal toads (Bufo boreas) in Glacier National Park, USA, we genotyped 551 individuals at 11 microsatellite loci and used Bayesian clustering methods to describe population genetic structure and identify barriers to gene flow. We found evidence of two primary genetic groups that differed substantially in elevation and two secondary groups within the high elevation group. There was also evidence of further substructure within the southern high elevation group, suggesting mountain ridges are barriers to gene flow at local scales. Overall, genetic variation was high, but allelic richness declined with increasing elevation, reflecting greater isolation or smaller effective population sizes of high altitude populations. We tested for Batrachochytrium dendrobatidis (Bd), the fungal pathogen which causes chytridiomycosis, and we found that 35 of 199 toads were positive for Bd. Unexpectedly, more heterozygous individuals were more likely to be infected. This suggests that dispersal facilitates the spread of disease because heterozygosity may be highest where dispersal and gene flow are greatest.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Population genetic structure and disease in montane boreal toads: More heterozygous individuals are more likely to be infected with amphibian chytrid
Series title Conservation Genetics
DOI 10.1007/s10592-015-0704-6
Volume 16
Issue 4
Year Published 2015
Language English
Publisher Kluwer Academic Publishers
Publisher location Dordrecht
Contributing office(s) Northern Rocky Mountain Science Center
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Conservation Genetics
First page 833
Last page 844
Country United States
State Montana
Online Only (Y/N) N
Additional Online Files (Y/N) N