Reconstructing geo-spatial and temporal patterns of Anadenanthera colubrina genetic diversity: coupling phylogeographical and species distribution modelling analyses

ZERDA, H.; PRADO, D.E.; BARRANDEGUY, M.E.; SAVINO, C.; GARCIA M.V.; DUSSET, F.; MOGNI, V. Y.

Foz de Iguazú

Congreso; 2018 International Congress of genetics; 2018

Sociedad Brasilera de Genética - Sociedad Argentina de Genética

The effects of Quaternary climatic fluctuations on the historical dynamics of Seasonally Dry Tropical Forests (SDTFs) was evaluated by means of phylogeographical analysis and species distribution modelling of Anadenanthera colubrina var. cebil, the most paradigmatic tree species of these forests. Two non-coding regions of plastid DNA (intron trnL and intergenic spacer trnF- trnL) were sequenced in 41 individuals from 19 South American locations. Two groups were defined with both Neighbour-joining tree and median-joining network analyses. These analyses showed Misiones and Sub-Andean Piedmont groups. Misiones group had higher number of haplotypes than Sub-Andean Piedmont group despite shorter geographical distance among individuals from Misiones. The divergence time estimated between haplotypes date in the Upper Pleistocene (93%) and Holocene (7%). Paleodistribution models suggested that species distribution showed an Amazonian expansion in the Last Glacial Maximum (22 kyr BP) and a contraction in the Holocene (6 kyr BP). However, present distribution showed an expansion and colonization southward in concordance with the species current distribution. These patterns could be explained by seasonality climatic variables. The phylogeographical groups showed concordance with the floristic units described for SDTFs. The low genetic diversity in Sub-Andean Piedmont suggests a recent southward expansion of the range of the species after the Holocene, supporting the hypothesis of the southward expansion of SDTFs. The spatial and temporal patterns of divergence in A. colubrina var. cebil could be associated with possible historical changes in the distribution instead of the geographical distances between the current distribution patches of the SDTFs.