Genetic diversity and population structure of Colletia paradoxa (Rhamnaceae) a medicinal species threatened with extinction in Brazil

Abstract

In order to obtain a better knowledge about the endangered species Colletia paradoxa (Rhamnaceae), which appears in fragmented populations, a study was carried out with six populations from different physiographic regions of Rio Grande do Sul and Santa Catarina states, Brazil. The objective of this study is to investigate the real conditions of genetic diversity in populations, through the use of inter simple sequence repeat (ISSR) molecular marker, and to evaluate the distribution of genetic diversity among and within populations, in order to plan conservation and management strategies. Five selected primers produced 112 DNA fragments in 46 samples from individuals that were evaluated. The result of the analyses showed 100% polymorphism. Nei’s genetic diversity index (H) was 0.3083. Shannon’s information index (I) was 0.4880. Bayesian inference of clustering performed by Structure revealed the most likely K = 4 to C. paradoxa. The analysis of molecular variance among all populations showed that the greatest genetic diversity occurs within the populations (82%), while among them there is less differentiation (18%), although in some populations good levels of genetic migration occur (Nm = 1.0465) indicating that genetic exchanges among populations of C. paradoxa are still occurring.