Analysis Of Genetic Diversity Among Different Populations Of Nasonia Vitripennis Based On Mtdna COI Gene Sequences And Association Of Wolbachia Infection With Host Mtdna Diversity

As a cosmopolitan species and emerging model system for developmental and evolutionary biology studies, the phylogeography of Nasonia vitripennis has only been investigated in Europe and North America. To investigate the genetic differentiation and diversity among different populations of the Nasonia vitripennis in China, we analyzed COI sequences of mitochondrial DNA in6geographical populations and compared with North American and European populations. In this study we also investigated Wolbachia infection in Nasonia vitripennis populations and analyzed association between Wolbachia infection status and the diversity of host COI. The main results are as followings:1. Analysis of genetic diversity among different populations of Nasonia vitripennis based on COI gene sequence(1) In this study, partial sequences of the mitochondrial COI gene of Nasonia vitripennis, collected from6localities in China, were sequenced and analyzed their genetic differentiation and diversity. Sequence analysis of the619bp mtDNA-COI gene from48individuals resulted in63haplotypes and97variable sites, including30parsimony informative sites and67were singleton sites. The average content of A+T is72.3%and the average content of G+C is27.7%. The average percentage of A+T15times higher than that of G+C, which shows a strong A+T bias.(2) The phylogenetic tree constructed using neighbor-joining method showed that three groups were clustered corresponding to their geographic locations of China, Europe and North America. Mantel test also revealed significant correlation between genetic and geographical distance.(3) The mean haplotype diversity and nucleotide diversity of all Chinese populations were0.856and0.00919respectively, which was higher than in North America but lower than the Europe. Xinjiang population closed to European and North American populations, showed significantly higher level of than other Chinese populations.(4) The average gene flow (Nm) among the6populations was0.65and the overall Gst value was0.277. The results suggested that Chinese Nasonia vitripennis populations in China keep a high level of population genetic differentiation due to gene flow, especially in ZheJiang and WuHu populations. Molecular variance (AMOVA) analysis indicated that the total genetic variance was attributable to variations among populations (68.36%).(5) The Tajima’s D neutrality tests in North American and European populations were not significant (P>0.05), but was significant (P<0.05) in China, which implied that there might be a population expansion in Chinese Nasonia vitripennis populations recently.2. Association of Wolbachia infection with host mtDNA diversity in different pupulations of Nasonia vitripennisAll the individuals from Xinjiang, WuHu and ZheJiang populations were infected with Wolbachia, while the Wolbachia infection rate of HeiLongJiang, NanLing and BeiJing populations were62.5%,57.1%and71.4%respectively. Compared with uninfected individuals in HeiLongJiang, NanLing and BeiJing populations, the infected groups was significantly lower than the uninfected groups in diversity of COI sequences.