Gene pool sharing and genetic bottleneck effects in subpopulations of Eschweilera ovata (Cambess.) Mart. ex Miers (Lecythidaceae) in the Atlantic Forest of southern Bahia, Brazil.

Alesandro S Santos,Cassio Van Den Berg,Polliana S Rodrigues,Fernanda Amato Gaiotto,Daniela B Borges,Roberto Tarazi,Caio V Vivas

doi:10.1590/1678-4685-gmb-2018-0140

Abstract

Forest loss and fragmentation are the main threats to the maintenance of the Atlantic Forest, an important global biodiversity hotspot. Because of the current critical level of deforestation, ecological corridors are needed to facilitate species dispersion and gene flow among fragments. This study was conducted to investigate the genetic variability and gene pool sharing of Eschweilera ovata in five forest remnants in southern Bahia, Brazil using nuclear simple sequence repeat (nSSR) and plastid simple sequence repeat (cpSSR) microsatellite markers. cpSSR marker analysis revealed the domains of four haplotypes, showing that 80% of the individuals had only four maternal origins, reflecting a founder effect and/or genetic bottleneck. The results of cpSSR and nSSR analyses indicated moderate genetic diversity, particularly in conservation units with full protection, which showed the best parameters of all areas evaluated. Another indication of the susceptibility of these populations to forest loss and fragmentation was the strong genetic bottleneck observed. In contrast, genetic structure analyses (FST and discriminant analysis of principal components) revealed gene pool sharing between the subpopulations, which may reflect the historical gene flow that occurred before forest fragmentation.

Highlights

The Atlantic Forest in the east of Brazil is an important center of endemism associated with high species richness of several taxa, tree species (Thomas et al, 1998; Myers et al, 2000; Martini et al, 2007; MurraySmith et al, 2008)
We developed 13 new nuclear primer pairs for E. ovata which had (i) an average of 5.6 alleles, (ii) HO of 0.214–1.000, (iii) HE of 0.198–0.878, and (iv) a fixation index (F) of -0.333–0.4763
The Ho values were always higher than the expected heterozygosity (Figure 3), which was reflected by the negative values of the inbreeding coefficient (Figure 4) and significant genetic bottleneck in the four subpopulations (Table 1)

Summary

Introduction

The Atlantic Forest in the east of Brazil is an important center of endemism associated with high species richness of several taxa, tree species (Thomas et al, 1998; Myers et al, 2000; Martini et al, 2007; MurraySmith et al, 2008). Despite its great importance for biodiversity conservation, this phytogeographical domain has been reduced to approximately 11–16% of its original area (Ribeiro et al, 2009). This anthropogenic forest reduction represents one of the main threats to the permanence of species in this environment by reducing resources and increas-. Enabling gene flow between fragments and corridors decreases the deleterious effects caused by isolation and the reduction of forest area that decrease populations and their genetic diversity, increasing the risk of local extinctions over time (Carvalho et al, 2015)

Methods

Results

Conclusion