Low Genetic Diversity and Moderate Inbreeding Risk of an Insular Endemic Pit Viper (Gloydius shedaoensis): Implication for Conservation
Gloydius shedaoensis is an insular endemic and vulnerable pit viper that is restricted to Snake Island, a very small islet in the Bohai Sea of northeastern China. In this study, we used the mitochondrial ND4 gene and eight microsatellite loci to evaluate the genetic structure and amount of genetic diversity in the species. In total, 63 individuals were sampled along eight line transects throughout the range of Snake Island. We found that this vulnerable species presented a remarkably low genetic diversity and moderate inbreeding. No evident genetic or phylogenetic structures were detected within the species, and only two neighboring subpopulations, S-pop1 and S-pop2, showed slight differentiations from others, suggesting the species can be considered as a single unit for future conservation effort. A high level of gene flow was found among subpopulations, and the analyses of relationships between values of individual relatedness and their spatial distributions further showed that closely related individuals tended to scatter throughout the entire island, suggesting widespread dispersals of the insular pit vipers.Abstract
The full view of Snake Island and the location of each sampled individual (black dots). Numbers show the sampling subpopulations (S-pop) and their corresponding locations. Two subpopulations S-pop2 and S-pop8 were sampled at the valley and the foot of mountain, respectively, and all other six subpopulations were sampled along hill ridges. The subpopulations S-pop7 and S-pop8 are not visible in the full view of Snake Island.
Median-joining network for five ND4 haplotypes in pit vipers on Snake Island. Distributions of each haplotype in sampled subpopulations are shown in numbers. The area of the circle is proportional to the haplotype frequency. The short lines in the network represent mutational steps.
The posterior probability Ln P(K) (mean and standard deviation) for each K (1–6) of pit vipers on Snake Island, based on 10 independent runs using STRUCTURE.
Spatial distributions of the top 15 most closely related relatives (grey dots) of each target subpopulation of pit vipers on Snake Island (A-H, highlighted by the black line). Both males and females were used for the analyses.
Correlation analyses between individual relatedness (r-values) and their corresponding geographic distances based on 53 individuals of pit vipers on Snake Island. Values of correlation coefficient (r) and significance level (P) are shown.
Contributor Notes
