基于线粒体ATP6基因全序列分析中国绵羊痒螨(兔亚种)的遗传多样性

为进一步了解我国绵羊痒螨(兔亚种)种群的遗传变异情况和分类情况,采用PCR技术扩增绵羊痒螨(兔亚种)虫株的线粒体ATP6基因全序列,并分析所得序列,旨在探讨中国华北、华东、华中、西北、西南地区绵羊痒螨(兔亚种)种群的遗传多样性和种群结构。本研究成功获得88条序列,长度均为672 bp,包含41个单倍型,表现出较高的遗传多样性(π=0.014 94)和单倍型多样性(Hd=0.925 81),且以种群内部的遗传变异为主(97.92%)。进一步分析发现,5个种群间遗传分化程度较弱(F_st=0.020 81),基因交流频繁(Nm=11.763 5),中性检验值(Tajima’s D=0.937 98,Fu’s Fs=0.522 06)为不显著的正值,结合错配分布曲线呈现多峰,表明我国绵羊痒螨(兔亚种)种群在进化过程中比较稳定,无种群扩张事件。从单倍型网络图和NJ树可知,中国绵羊痒螨(兔亚种)没有形成基于兔品种、温度带或地理分布的遗传结构。中国绵羊痒螨(兔亚种)种群遗传多样性高,但种群间无明显分化,未形成基于兔品种、温度带或地理分布的遗传结构。

Genetic diversity analysis of Psoroptes ovis var. cuniculi by full-length of mitochondrial ATP6 gene in China

To explore the genetic variation and genetic taxonomy of Psoroptes ovis var. cuniculi in China, the complete sequence of mitochondrial ATP6 gene of P. ovis var. cuniculi isolated from 5 geographical regions (Huabei, Huadong, Huazhong, Xibei, and Xinan) were amplified by PCR sequencing techniques, and evaluated the genetic diversity and population structure of P. ovis var. cuniculi population. Eighty-eight sequences of mitochondrial ATP6 were obtained which were 672 bp, including 41 haplotypes. The whole population of P.ovis var. cuniculi in China showed high genetic diversity (π=0.014 94) and haplotype diversity (Hd=0.925 81), and the genetic variation within the population held the dominant positon(97.92%). The genetic differentiation index among the five populations was low (F_st=0.02081), and there was no obvious differentiation and frequent gene exchange (Nm=11.763 5). In P. ovis var. cuniculi population, the average values of Tajima’s D and Fu’s Fs were positive (Tajima’s D=0.937 98, Fu’s Fs=0.522 06) and there was no significant differentiation(P>0.05). The mismatch distribution curve showed multiple peaks, indicating that the population of P. ovis var. cuniculi was relatively stable in the evolutionary process and had no population expansion events. From NJ phylogenetic tree and haplotype network map, it can be seen that there was no genetic structure based on rabbit breed, temperature zone or geographical distribution. The results revealed that there was high level of genetic diversity, little population genetic differentiation, but population structure has not formed according to rabbit breed, temperature zone or geographical distribution.