Analysis on the genetic diversity and structure of Isoetes taiwanensis based on nuclear and chloroplast DNA sequences

We employed both nuclear and chloroplast DNA sequences to analyze the genetic diversity and structure of 20 individuals from two separate populations of Isoetes taiwanensis, with some suggestions for the conservation of this species also proposed. In the nuclear DNA data set, 18 haplotypes were discovered, with a haplotype diversity of 0.9842 and nucleotide diversity of 0.00215. In the chloroplast DNA data set, six haplotypes were detected, with a haplotype diversity of 0.6211 and nucleotide diversity of 0.00326. AMOVA results indicated that genetic variations within populations were larger than those among populations. Based on nucleotide DNA sequences, gene flow was 4.26 and G_st was 0.05543. Compared with other Isoetes species, the nucleotide diversity of I. taiwanensis was relatively low, possibly related to the ploidy level and narrow distribution. The genetic structure is likely related to strong gene flow and foundation effects. Both in situ and ex situ conservation is recommended.