Caracterização da diversidade genética de Bothrops insularis baseada em sequências de microssatélites

Abstract

Bothrops insularis or the Golden lancehead is a critically endangered species endemic to Queimada Grande Island, São Paulo. Due to its vulnerability, five ex situ populations have been kept in four Research Institutes for breeding and conservation purposes. B. insularis has been studied based on natural history, evolution, ecology and venom content. However, genetic diversity approaches are still scarce, although this is a crucial parameter to the development and maintenance of conservation programs. Herein, we aimed to: (i) characterize and compare the genetic diversity of the ex situ population (housed at the Laboratório Especial de Ecologia e Evolução, Instituto Butantan) to representatives of the in situ population; and (ii) test the existence of genetic structure, and inter/intrapopulational genetic divergence. This study was carried out using twelve heterospecific microsatellite markers obtained from three species of Bothrops neuwiedi group. Our results recovered low to medium genetic diversity parameters, with the highest genetic variability detected in the ex situ population. Both populations showed low but significant values of pedigree (kinship) inbreeding coefficient, as expected for threatened species, and/or with restricted geographic distribution. Moreover, the negative values of mating systems inbreeding coefficient may be related to mechanisms that cause inbreeding avoidance in the populations. The interpopulational differences of allelic frequencies and the presence of private alleles could be related to genetic drift, demographic events, and/or absence of representatives from one region of the island. Despite these divergences, none of the population differentiation indices showed significant values and, therefore, there are no evidences of genetic differentiation between the ex situ and in situ population. Genetic distance and discriminant analysis of principal components (DAPC) approaches recovered five genetic clusters. However, these clusters do not recover any geographic relationship among representatives of the in situ population, and they are not totally explained due to consanguinity relationships as well. Based on the information herein presented, we conclude that further studies using genetic markers (new microssatelites, SNPs, for instance) are needed to achieve more information related to genetic diversity of Bothrops insularis, and to investigate its genetic structure.