Assessment of intra and interregional genetic variation in the Eastern Red-backed Salamander, Plethodon cinereus, via analysis of novel microsatellite markers.

Alexander C Cameron,Robert B Page,Jeffry J Anderson

doi:10.1371/journal.pone.0186866

Alexander C Cameron, Robert B Page + Show 1 more

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https://doi.org/10.1371/journal.pone.0186866

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Abstract

The red-backed salamander (Plethodon cinereus) has long-served as a model system in ecology, evolution, and behavior, and studies surveying molecular variation in this species have become increasingly common over the past decade. However, difficulties are commonly encountered when extending microsatellite markers to populations that are unstudied from a genetic perspective due to high levels of genetic differentiation across this species’ range. To ameliorate this issue, we used 454 pyrosequencing to identify hundreds of microsatellite loci. We then screened 40 of our top candidate loci in populations in Virginia, Pennsylvania, and Ohio—including an isolated island population ~ 4.5 km off the shore of Lake Erie (South Bass Island). We identified 25 loci that are polymorphic in a well-studied region of Virginia and 11 of these loci were polymorphic in populations located in the genetically unstudied regions of Ohio and Pennsylvania. Use of these loci to examine patterns of variation within populations revealed that South Bass Island has low diversity in comparison to other sites. However, neither South Bass Island nor isolated populations around Cleveland are inbred. Assessment of variation between populations revealed three well defined genetic clusters corresponding to Virginia, mainland Ohio/Pennsylvania, and South Bass Island. Comparisons of our results to those of others working in various parts of the range are consistent with the idea that differentiation is lower in regions that were once glaciated. However, these comparisons also suggest that well differentiated isolated populations in the formerly glaciated portion of the range are not uncommon. This work provides novel genetic resources that will facilitate population genetic studies in a part of the red-backed salamander’s range that has not previously been studied in this manner. Moreover, this work refines our understanding of how neutral variation is distributed in this ecologically important organism.

Highlights

Since the latter half of the 20th century, the Eastern Red-backed Salamander (Plethodon cinereus; from here out ‘red-backed salamander’) has been the subject of hundreds of ecological, evolutionary, and behavioral studies [1,2]
The results of BLASTn searches of NCBI’s nr/nt database using 454 fragments containing molecularly pursued PALs as queries are given in S1 Table
Of the 40 PALs selected for molecular screening in Washington and Lee University (WLU), we identified a set of 27 loci that exhibited a high rate of successful amplification (Table 2)

Summary

Introduction

Since the latter half of the 20th century, the Eastern Red-backed Salamander (Plethodon cinereus; from here out ‘red-backed salamander’) has been the subject of hundreds of ecological, evolutionary, and behavioral studies [1,2]. In addition to being highly abundant, red-backed salamanders act as a topdown regulator within the detrital food web [5,6,7] These attributes exemplify why the redbacked salamander has served as an excellent model for examining a wide variety of interesting topics including: territoriality [8,9], the dynamics of complex social systems [10,11], phenotypic variation [12,13], fine-scale population differentiation [14,15], and the effects of anthropogenic modifications of the landscape on gene flow [16,17]. While synthesis across studies based on modern molecular techniques [14,17,21,22] is generally consistent with the findings of Highton and Webster ([24]; see discussion), most of the red-backed salamander’s range has not been investigated via contemporary approaches to population genetics

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