基于线粒体Cytb基因序列的山瑞鳖保种群体遗传多样性分析

Genetic diversity analysis of Palea steindachneri conservation populations based on mitochondrial Cytb gene sequence

为研究云南地区山瑞鳖(Palea steindachneri)保种群体遗传多样性和遗传结构。该研究基于线粒体细胞色素b(Cytb)基因,利用PCR扩增和测序技术,分析了2个云南地区山瑞鳖保种群体的单倍型分布情况、遗传距离、遗传结构和群体历史动态等,扩增得到F_(3)代群体和F_(4)代群体共45个个体的线粒体Cytb基因序列。用DNAStar和MEGA软件剪切校对后序列长度为1000bp,碱基A、T、C和G的平均含量分别为31.28%、27.19%、30.18%和11.35%。在两个群体中共检测到9种单倍型,其中F_(3)代群体有7种单倍型,F_(4)代群体有3种单倍型,单倍型间没有明显的谱系结构,亲缘关系较近。两个群体内遗传背景单一,个体间平均遗传距离较小,随着保种代数的增加群体的遗传多样性水平也在逐渐降低,近交现象明显。中性检验和核苷酸歧点分布图显示,F_(3)代群体和F_(4)代群体历史上可能经历过扩张。研究结果表明,该保种群体的群体内遗传多样性较低,在今后的保种过程中应采取不同的保种策略,避免近亲繁殖。

To study the genetic diversity and genetic structure of Palea steindachneri conserved populations in Yunnan.In this study,we analyzed the haplotype distribution,genetic distance,genetic structure and population history dynamics of two populations of Palea steindachneri conserved in Yunnan,based on the mitochondrial cytochrome b(Cytb)gene,using PCR amplification and sequencing techniques,and amplified the mitochondrial Cytb gene sequences of 45 individuals from the F_(3) and F_(4) generation populations.The sequence length was 1000 bp after cut and aligned with DNAStar and MEGA software,and the average contents of bases A,T,C and G were 31.28%,27.19%,30.18%and 11.35%,respectively.A total of nine haplotypes were detected in the two populations,including seven haplotypes in the F_(3) generation population and three haplotypes in the F_(4) generation population,with no obvious genealogical structure between haplotypes and close kinship.The genetic background within the two populations was single,and the average genetic distance between individuals was small.The genetic diversity level of the populations was gradually decreasing with the increase of the number of conserved generations,and the inbreeding phenomenon was obvious.The neutrality test and nucleotide manifold distribution maps indicated that the F_(3) and F_(4) populations may have undergone expansion historically.The results indicated that the conserved population had low intra-population genetic diversity,and different conservation strategies should be adopted to avoid inbreeding in the future conservation process.