Patterns of genetic variability in central and peripheral populations of Dipteryx alata (Fabaceae) in the Brazilian Cerrado
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2015
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Resumo
This study tested whether genetic parameters in
Dipteryx alata populations, estimated from genomic and
chloroplastidial microsatellite markers, were distributed
according to a central-peripheral model, inferring which
factors drive this spatial distribution of genetic variability
within populations. For each of the 23 populations sampled
throughout the species’ range, the mean number of alleles
per locus, expected heterozygosity and intrapopulation
fixation indices were calculated using a rarefaction
approach based on 54 alleles from 8 nuclear microsatellites.
Explanatory variables were grouped into three subsets:
the ecological suitability estimated by combining
different techniques of ecological niche modeling, variables
expressing human occupation, and a historical variable
represented by the first eigenvector from the pairwise
FST matrix based on cpDNA microsatellites. Each response variable was modeled using first (linear) and second
(quadratic) order trend surface analysis (TSA). Multiple
regressions were then used to evaluate the relative effects
of the explanatory variables, based on AIC multi-model
selection. In general, the genetic parameters did not follow
a classical central-periphery model. Ecological suitability
had a significance influence in all genetic parameters, so
more suitable regions have higher genetic diversity and
low endogamy. There was also a relationship between
fixation indices and human impacts. The high genetic
diversity in the southwestern region of Cerrado suggested
that recent range expansion (after the Last Glacial Maximum)
may also influenced the observed intrapopulation
genetic patterns. Thus, complex combinations of both
historical and ecological drivers, as well as contemporary
human occupation, seem to drive current genetic composition
within D. alata populations throughout its geographic
range.
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Conservation, Microsatellite, Niche model, Tropical tree
Citação
SOARES, Thannya N. et al. Patterns of genetic variability in central and peripheral populations of Dipteryx alata (Fabaceae) in the Brazilian Cerrado. Plant Systematics and Evolution, Heidelberg , v. 301, p. 1315-1324, 2015.