| The double-striped cockroach Blattella bisignata is endemic to Asia, and this species is widely distributed in the wild. B. bisignata has the advantage of migration comparing with other cockroaches because it has ability of short-time flying. The Asia area is the epicenter for cockroaches and one of the biodiversity hot spots. To date, there has been few study focused on the phylogeography of the cockroach in this area.In this study, we screened 11 single-copy anonymous nuclear markers for B. bisignata from a genomic library. After sequencing 30 individuals, a total number of 151 variable sites or SNPs were recognized in 4157 bp sequenced markers. The most polymorphic loci is AL12, while the least is AL57. These loci can amplify in other two Blattella species(B. germanica and B. lituricollis), and cross-species amplification success reduced with the increasing genetic distance in other cockroaches.To preliminarily study whether the complex terrains in southern China and the Quaternary glaciation events affect the current distribution of B. bisignata, we chose 3 anonymous nuclear loci and COI as molecular markers in the study of its population structure. In total,106 individuals collected from 11 sampling sites in southern China were used. The results based on these 4 markers showed the Guangxi and Xishuangbanna populations had higher genetic diversity than other populations, which indicated this area may be the origin of B. bisignata or the refugia during Quaternary glaciation. Two main clades were discovered in Maximum parsimony (MP), Neighbor-joining (NJ) trees and median-joining (MJ) network phylogenetic analyses based on these markers. The boundary of these two clades was the Yunnan-Guizhou Plateau. We didn’t detect any population explosion in the species history. We can’t clearly reveal how climate, terrain and other factors impact the population structure of B. bisignata, which deserves further study in the near future. |
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