Population genetic structure and disease in montan

Authors: Brett R Addis Winsor H Lowe Blake R Hossack Fred W Allendorf

Publish Date: 2015/02/13

Volume: 16, Issue: 4, Pages: 833-844

PDF Link

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 greatestWe thank Tom Brekke Kris Crandell Sara Dykeman Nate Muhn Paul Scarr and numerous field technicians who collected samples between 2008 and 2011 Sally Painter and Steve Amish provided assistance with lab work and genotyping Marty Kardos provided assistance with randomization tests and Eric Fuchs provided statistical advice This manuscript was improved with comments from Mike Schwartz This research was performed under University of Montana IACUC permit 02209WLDBS051209 Partial funding was provided by the Jerry O’Neal student fellowship and the US Geological Survey Amphibian Research and Monitoring Initiative ARMI This manuscript is ARMI product number 499 Use of trade product or firm names does not imply endorsement by the US Government

Keywords: