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.

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.

Using multiple analytical methods to improve phylogenetic hypotheses in Minaria (Apocynaceae).

Metastelmatinae is a neotropical subtribe of Asclepiadoideae (Apocynaceae), comprising 13 genera and around 260 species whose phylogenetic relationships are often unresolved or incongruent between plastid and nuclear datasets. The genus Minaria is one of the first lineages to emerge in the Metastelmatinae and is highly supported based on plastid markers. It comprises 21 species, most of which are endemic to small areas with open vegetation in the Espinhaço Range, Brazil. In the work presented here, we use plastid (rps16, trnH-psbA, trnS-trnG, and trnD-trnT) and nuclear (ITS and ETS) datasets to investigate the relationships within Minaria. We show that the three methods mostly used in phylogenetic studies, namely, maximum parsimony, maximum likelihood, and Bayesian Inference, have different performances and that a pluralistic analytical approach combining results from them can increase tree resolution and clade confidence, providing valuable phylogenetic information.