Genetic Diversity and Population Structure of as Revealed by Mitochondrial DNA Sequences.

Soil macrofauna, such as , are an important component of ecosystems. However, systematic studies of the genetic diversity, population genetic structure, and the potential factors affecting the genetic differentiation of are lacking. We performed a population genetic study of 166 individuals from the mountains to the south of the Yangtze River, north of the Yangtze River in Nanjing city, and near Tianjin city, in order to investigate the correlations between geographical distance and genetic diversity. A total of 1182 bp of and gene sequences of mitochondrial DNA, and 700 bp of the 18S rRNA gene sequence were analyzed. There were two haplotypes and one variable site in the 18S rRNA gene, and 28 haplotypes and 78 variable sites in the and genes. In this study, the 18S rRNA gene was used for species identification, and mtDNA (concatenated sequences with and ) was used for population genetic analysis. Structure cluster analysis indicated that the genetic structures of the different populations of tended to be consistent at small geographical scales. Phylogenetic trees revealed that the haplotypes were clearly divided into three branches: the area south of the Yangtze River, the area to the north of the Yangtze River in Nanjing, and the area in Tianjin. Large geographical barriers and long geographical distance significantly blocked gene flow between populations of . Our results provide a basic theoretical basis for subsequent studies of millipede taxonomy and population genetic evolution.