Genetic diversity of Anadenanthera colubrina Vell. (Brenan) var cebil, a tree species from the South American subtropical forest as revealed by cpSSR markers

Abstract

Abstract Anadenanthera colubrina var cebil is a tree species native to the Upper Parana Atlantic Forest where human activities have severely impacted causing deep fragmentation. Microsatellites are not available in this species. Therefore, the first objective of this study was to generate chloroplast simple sequence repeats (cpSSR) by cross-species transfer. Understanding the evolutionary dynamics of subdivided populations is an important matter. In this way, a first approach to the characterization of the haplotypic diversity within and between populations as well as the genetic structure of native Argentinean populations were the main goals of this study. Twenty four individuals from two populations of the Misiones province were studied and four cpSSR loci were tested. Two of them exhibited polymorphic patterns leading to the identification of 11 cpDNA haplotypes with high mean genetic diversity (GD=0.73). The minimum spanning network defined three clear groups which can be assigned to at least three subpopulations. AMOVA indicated that the total variance showed the highest percentage of variation (48%) within subpopulations with a fixation index (FST) statistically significant (FST=0.520; p<0.05). Brown’s two loci component analysis indicated that substructure population is present. Jost’s differentiation global index (Dest) was 0.049 while Dest pairwise comparison reflected a certain level of genetic structure. The high diversity level detected in the adult trees of A. colubrina var cebil from the populations under study could be due to recent human influence. In this way, the reduction in population size caused a reduction in the number of trees leading to surviving trees showing the historical diversity of the populations analyzed.