Long-distance gene dispersal inferred from spatial genetic structure in Handeliodendron bodinieri, an endangered tree from karst forest in southwest China

Abstract

Handeliodendron bodinieri is an endangered tree endemic to the karst forest in southwest China, which is characterized by its high species richness and endemism but severely destroyed by recent human activities. We explored the genetic diversity and spatial genetic structure in H. bodinieri using 18 nuclear microsatellite loci. Genetic diversity within populations was found to be moderate (average HE = 0.489), whereas population differentiation was low (FST = 0.047). However, a general and significant heterozygote excess was found for all analyzed populations, with a mean FIS of −0.291. Spatial autocorrelation analysis indicated moderate spatial genetic structure (Sp = 0.018–0.029) in this species. Indirect estimates revealed long distance gene dispersal, with the values of σg ranging from 786 m to 1400 m, suggesting effective genetic connectivity among populations in the study area. These results suggest that the karst landscape is not a barrier of gene flow at regional scale for H. bodinieri.