Genetic differentiation in Aspidosperma polyneuron (Apocynaceae) over a short geographic distance as assessed by AFLP markers

Abstract

ABSTRACT. Studies on intraspecific variation can contribute to the development of conservation strategies by identifying units of conservation for threatened species. Aspidosperma polyneuron is a tropical tree of seasonal semideciduous forests that is currently endangered and protected because it has been heavily logged for lumber, although it was once common in Brazil and neighboring countries. We investigated genetic structure in two samples of A. polyneuron collected from steep hillsides and from flat areas of a natural forest fragment in northern Paraná State, Brazil. Seven AFLP primer combinations yielded 200 markers, with a polymorphic rate of 88.5% for samples from the flat area and 99% for samples from the high declivity area. Total genetic diversity (H T ) was 0.387, while the genetic diversity Genetic differentiation in Aspidosperma polyneuron within the populations (H S ) was 0.307 and 0.372, for samples from the flat and the high declivity areas, respectively. Genetic differentiation between samples was high, with a mean F ST of 0.265 and a genetic distance of 0.148, indicative of a high degree of genetic structure over a short distance. Principal coordinate analysis separated the samples into three groups of individuals; the first group included individuals from the high declivity area, the second group consisted of individuals only from the flat area, and the third group had individuals from both areas. Bayesian analysis also showed K = 3 clusters. The unexpected high level of intraspecific variation of A. polyneuron in this small forest fragment should be taken into account when evaluating the genetic impact of forest degradation on this species in other semideciduous forest fragments.

Genetic diversity and fragmentation of Aspidosperma quebracho-blanco (Apocynaceae) natural habitats, conservation issues in Chaco forest and savanna biomes

“…& Zucc. showed the occurrence of values below 40% both in the number of amplified sequences and in the polymorphisms found by primers (Damasceno et al, 2011;Ferreira-Ramos et al, 2011;Zimback et al, 2011). In addition to this problem, which involves increased spending and time to obtain the results, DNA extraction from Aspidosperma leaves may be compromised due to the presence of a wide variety of alkaloids (Schumutz, 1960;Molinari & Crochemore, 2001;Sahu et al, 2012), and polysaccharides (Freitas, 2008), which are responsible for possibly inhibiting Taq DNA polymerase in the PCR (Demeke & Adams, 1992;Fang et al, 1992).…”

Genetic Structure and Diversity of Brazilian Tree Species from Forest Fragments and Riparian Woods

“…The species of late successional stages, considered here, represent the first or second generation postfragmentation and thus are believed to reflect the immediate consequences of the fragmentation process. Interestingly, one of the secondary species studied, Aspidosperma polyneuron, was found in a continuous distribution, in a plateau followed by a high declivity , and the other, Maythenus aquifolium, was found in fragments separated by up to 30 km (Sayhun et al, 2010); however, the F ST values observed in the two situations were similarly high, suggesting that part of the genetic differences found between the populations of these species also linked to adaptive characteristics (Sayun et al 2010;Damasceno et al, 2011).…”