Abstract:
We examined chloroplast trnL intron sequence variation within Isoetes hypsophila, a Chinese endemic alpine
quillwort species. Sequence data were obtained from 46 individuals in six populations throughout the natural
distribution of the species. Sequences appeared to have neutral evolution (Tajima’s criterion D ¼ 1:66453,
0:1 > P > 0:05; Fu and Li’s test D ¼ 1:92897, 0:1 > P > 0:05; F ¼ 2:17823, 0:1 > P > 0:05). Eleven
haplotypes were identified in I. hypsophila. A relatively high level of haplotype diversity (h ¼ 0:817) and a low
level of nucleotide diversity (p ¼ 0:0045) were detected in I. hypsophila. Indirect estimates of gene flow based on
cpDNA variation revealed significant genetic differentiation between the ZD1 population in Yunnan Province
and the populations from Sichuan Province. High genetic differentiation between Yunnan and Sichuan
populations was consistently indicated by both hierarchical analyses of molecular variance (AMOVA;
GST ¼ 0:5011) and the structure of a neighbor-joining tree. From nested clade analysis, restricted gene flow
with isolation by distance was inferred to be responsible for the current spatial genetic structure of I. hypsophila.
