Chloroplast DNA variation of Tilia cordata Mill. (Tiliaceae)

The distribution of haplotypic diversity of 17 Tilia cordata Mill. populations was investigated by PCR–RFLP markers of the chloroplast genomes. A high number of haplotypes (14) and high total genetic diversity (hT = 0.881) were detected. The distribution of the chloroplast DNA haplotypes revealed low geographic structure of the genetic diversity; the coefficient of differentiation between populations, Gst = 0.552, was lower than the mean value reported for maternally inherited markers in Angiosperm tree species. The value of population subdivision for ordered alleles, asmeasured by Nst, was significantly higher than the value of population subdivision for unordered alleles (Nst = 0.662, Gst = 0.552), thus indicating the presence of a phylogeographic structure. The relatively low genetic differentiation among T. cordata populations may be explained mainly as a consequence of human impact on this species.