10.5061/DRYAD.S6F76
Jaeger, Collin P.
Northern Illinois University
Duvall, Melvin R.
Northern Illinois University
Swanson, Bradley J.
Central Michigan University
Phillips, Christopher A.
University of Illinois at Urbana Champaign
Dreslik, Michael J.
Northern Illinois University
Baker, Sarah J.
University of Illinois at Urbana Champaign
King, Richard B.
Northern Illinois University
Data from: Microsatellite and major histocompatibility complex variation
in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus)
Dryad
dataset
2017
2017-04-08T00:00:00Z
2017-04-08T00:00:00Z
en
https://doi.org/10.1002/ece3.2159
22166334 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Genetic diversity is fundamental to maintaining the long-term viability of
populations, yet reduced genetic variation is often associated with small,
isolated populations. To examine the relationship between demography and
genetic variation, variation at hypervariable loci (e.g., microsatellite
DNA loci) is often measured. However, these loci are selectively neutral
(or near neutral) and may not accurately reflect genomewide variation.
Variation at functional trait loci, such as the major histocompatibility
complex (MHC), can provide a better assessment of adaptive genetic
variation in fragmented populations. We compared patterns of
microsatellite and MHC variation across three Eastern Massasauga
(Sistrurus catenatus) populations representing a gradient of demographic
histories to assess the relative roles of natural selection and genetic
drift. Using 454 deep amplicon sequencing, we identified 24 putatively
functional MHC IIB exon 2 alleles belonging to a minimum of six loci.
Analysis of synonymous and nonsynonymous substitution rates provided
evidence of historical positive selection at the nucleotide level, and
Tajima's D provided support for balancing selection in each
population. As predicted, estimates of microsatellite allelic richness,
observed, heterozygosity, and expected heterozygosity varied among
populations in a pattern qualitatively consistent with demographic history
and abundance. While MHC allelic richness at the population and individual
levels revealed similar trends, MHC nucleotide diversity was unexpectedly
high in the smallest population. Overall, these results suggest that
genetic variation in the Eastern Massasauga populations in Illinois has
been shaped by multiple evolutionary mechanisms. Thus, conservation
efforts should consider both neutral and functional genetic variation when
managing captive and wild Eastern Massasauga populations.
DataArchive