基于COⅠ基因序列的泥鳅、大鳞副泥鳅选育群体杂交子代遗传多样性分析

Genetic diversity analysis of hybrid offsprings of selective breeding population of Misgurnus anguillicaudatus and Paramisgurnus dabryanus based on COⅠ gene sequence

摘要:

为评估泥鳅、大鳞副泥鳅选育群体的遗传育种潜力,通过聚合酶链反应(PCR)扩增和一代测序技术,获得经两代群体选育的泥鳅自繁(M)、大鳞副泥鳅自繁(P)及其正交(MP)、反交(PM)等4个子代泥鳅种群的线粒体细胞色素氧化酶亚基Ⅰ基因COⅠ片段,并分析了其遗传多样性和群体结构。结果显示:(1)4种泥鳅的COⅠ基因片段碱基组成相似,均表现为A+T的含量(54.0%~56.2%)高于C+G的含量(43.8%~46.4%)；(2)4种泥鳅COⅠ基因片段的682个位点中,共检测到135个多态位点(占19.79%),其中128个为简约信息位点,7个为单碱基变异位点,变异均为转换或颠换,未发现碱基的插入与缺失；(3)M、P、MP、PM各定义15个单倍型,单倍型多态性均为1.000±0.024,核苷酸多态性分别为0.020 66±0.006 48、0.025 80±0.002 31、0.029 61±0.005 62和0.022 30±0.001 94,均具有高单倍型多样性和高核苷酸多态性；(4)M、P、MP、PM种内遗传距离分别为0~0.020、0~0.024、0~0.027和0~0.023,种间遗传距离为0.024~0.180,系统发育分析结果显示,MP与M亲缘关系更近,PM与P亲缘关系更近,体现出明显的偏母系遗传效应。研究结果表明,泥鳅、大鳞副泥鳅两个选育群体具有较高的遗传多样性,可分别经进一步群体选育后用于培育具有优势性状的杂交泥鳅新品种。

Abstract:

In order to evaluate the genetic and breeding potential of selective breeding population of Misgurnus anguillicaudatus and Paramisgurnus dabryanus,and provide theoretical and practical basis for the utilization of heterosis and breeding program,PCR amplification and first-generation sequencing technology were used to obtain the mitochondrial cytochrome c oxidase subunit Ⅰ(COⅠ) gene fragment sequences of four loach species,including self-propagated offsprings of M. anguillicaudatus(M),self-propagated offsprings of P.dabryanus(P),orthogonal offspring(MP) and anti-cross offspring(PM),and then the genetic diversity and evolution history of the four loach species were analyzed.The results showed as follows:(1)The base composition of COⅠ gene fragments in all of the four loaches species were similar,and the content of A+T(54.0%-56.2%) was higher than that of C+G(43.8%-46.4%).(2)A total of 135 polymorphic loci(19.79%) were detected in the 682 loci of COⅠ gene fragment of 4 loach species,including 128 simple information loci and 7 single base variation loci.The main variation included conversion and transposition,without base insertion or deletion.(3)Each of 15 haplotypes was defined in M,P,MP and PM, respectively.The four loach species had the same haplotype diversity of 1.000±0.024,while had different nucleotide polymorphisms as 0.020 66±0.006 48,0.025 80±0.002 31,0.029 61±0.005 362 and 0.022 30±0.001 94,respectively.All of them showed had high haplotype diversity and high nucleotide polymorphism.(4)The genetic distances were ranged from 0 to 0.020,0 to 0.024,0 to 0.027 and 0 to 0.023 within the population of M,P,MP and PM,respectively.The interspecific genetic distances were ranged from 0.024 to 0.180 among the four populations.The phylogenetic analysis showed that MP was closer to M,and PM was closer to P,showed obvious maternal effect.The results indicated that the selective breeding populations of M. anguillicaudatus and P. dabryanus had high nucleotide polymorphism and could be used as parents for further selective breeding,and then used for economic hybridization to breed new hybrid loach varieties with dominant characters.