Inferring male population structure of Myotis lucifugus using Y-chromosome markers

Abstract

The little brown bat (Myotis lucifugus) is a vagile species occupying a large distributional throughout most of North America. Myotis lucifugus separate into female maternity colonies to rear their young, and males appear to be solitary during the summer. In the fall males and females congregate for mating at hibernacula, after which they hibernate for the winter. In many mammalian species males are the primary dispersers causing gene flow between populations. Y chromosome markers can be used to characterize male specific population dynamics. White-nose syndrome (WNS) is a fungal infection that disturbs hibernating bats, and is distributed through physical contact between bats. Y chromosome sequences that show high conservation allow for cross species amplification. The 7th intron of the DBY gene and the 1st intron of the SMCY gene show conserved primer binding sites allowing for amplification in species without a characterized Y chromosome. SMCY1 locus was split into the SMCY1a and SMCY1b loci due to its length for better sequencing product. After optimization of the sequencing reaction 111 individuals were sequenced at these three loci. Aligned sequences showed eight haplotypes and nine variable sites across both the DBY7 and SMCY1b loci. An analysis of molecular variance (AMOVA) for the DBY7 and SMCY1b loci showed no statistically significant level of genetic structuring of Y chromosome haplotypes. A low transition transversion ratio was found for both loci, which suggests mutation bias. Low variability in intron sequences can be combined with variable microsatellites to better characterize male population structure.