5个大鳞副泥鳅家系的遗传结构分析

Genetic Structure Analysis of Five Families of Paramisgurnus dabryanus

利用20个微卫星标记对5个大鳞副泥鳅（Paramisgurnus dabryanus）家系的遗传结构进行分析,探究家系遗传多样性及其亲缘关系的远近,为进一步遗传选育提供技术参数。结果显示,20个微卫星标记在5个家系中共检测到等位基因数53个,平均等位基因数2.65个,各位点的等位基因数2-4个;5个家系平均观测杂合度（Ho）0.3117-0.5542,平均期望杂合度（He）0.3261-0.4371,平均多态信息含量（PIC）0.3459-0.4538,平均固定系数（Fis）-0.0472（〈0）,遗传分化系数（Fst）0.2703;UPGMA聚类分析显示,AB2013F-7和AB2013F-81亲缘关系最远。研究表明,5个家系间遗传分化较大,具备较大的选育空间。

The pedigree method is one of the main methods for genetic breeding of fish because it reduces inbreed- ing and maintains gene diversity. An understanding of the genetic structure of Paramisgurnus dabryanus guides the breeding of this species. 20 microsatellite markers were used to investigate the genetic diversities and kinship of five Paramisgurnus dabryanus families （ AB2013F-7, AB2013F-81, AB2013F-27, AB2013F-74, AB2013F-77 ） and the results provided technical parameters for selective breeding. The pectoral fins of 142 individuals from the five fami- lies were sampled and preserved with 95% ethanol. Genomic DNA was extracted from the pectoral fins using the phenol-chloroform extraction technique. PCR was performed in 20 μL solution （2×Mix 10 μL,H20 7μL, DNA 1 μL） and the PCR products were analyzed using Popgene 32 software. A total of 53 alleles were detected in the five families of P. dabryanus in 20 simple sequence repeats （SSRs）. The mean number of alleles was 2.65 with the number of alleles per locus ranging from two to four. The average observed heterozygosity （Ho ）, average expec- ted heterozygosity （He ） and average polymorphic information content （PIC） for the five families ranged, respec- tively, from 0. 3117 to 0. 5542 and 0. 3261 to 0. 4371,0. 3459 to 0. 4538. The average fixed coefficient （Fa） was -0.0472 （ 〈 0） and the genetic differentiation coefficient （ Fst ） was 0. 2703. Cluster analysis using the unweighted pair group method with arithmetic mean （UPGMA） showed the kinship of families AB2013F-7 and AB2013F-81 is the most distant. The results of this study indicate genetic differentiation among the five P. dabryanus families is sufficient for good breeding potential.