“鲆优1号”牙鲆和亲本群体的表型及遗传性状变异分析

Analysis of phenotype and genetic variation of on“Flounder No.1”Paralichthys Olivaceus and their parental populations

牙鲆是我国及大西洋沿岸天然捕捞和养殖的主导品种，对其遗传资源保护及养殖新品种开发具有重要的意义。本文对人工培育的牙鲆养殖新品种“鲆优1号”（ZJ）、其父本韩国牙鲆群体（KS）、母本F0750家系（JX）的18个表型性状进行测量，利用SSPS程序进行方差分析和多重比较，发现体长／体宽，头长／眼径，头长／眼间距、眼径／眼间距，侧线鳞和尾鳍条6个性状与父本或母本具有显著性差异（p〈0．05），可做为鉴别“鲆优1号”的标志性表型性状。“鲆优1号”与母本无显著差异（p〉0．05）性状占50％。与父本无显著性差异（p〉0．05）性状占33．33％。筛选了24个多态性微卫星引物对KS、JX、ZJ和FJ的遗传多样性进行分析，总共扩增出143个等位基因。4个群体的平均等位基因数（Na）大于平均有效等位基因数（Nac），平均观测杂合度大于平均期望杂合度，多态信息含量（PIG）分析显示：KS〉JX〉FJ〉ZJ，说明人工选育导致了遗传杂合度的降低。24个微卫星位点在4个牙鲆群体中的遗传偏离指数（D）在-0．7597到0．1884之间，在KS、JX、ZJ和FJ群体中分别有10、16、11和17个位点显著（p〈O．05）或极显著（p〈0．01）偏离Hardy-Weinberg平衡。24个基因位点的遗传分化系数（R）在0．0767N0．2586之间，平均为0．1468，表明14．68％的变异来自种群间，85．32％的变异来自种群内。Nei’s遗传距离显著，KS和FJ遗传距离最近（0．2825），遗传相似系数最大（0．7539）；ZJ与JX遗传距离最大（0．4205），遗传相似系数最小（0．6567）。本文研究表明：“鲆优1号”具有明显的表型和遗传特征，与父母本及反交群体比较发生了一定程度的种内和种群间遗传分化，为“鲆优1号”的种质鉴别提供了理论依据。

Japanese flounder （Paralichthys olivaceus） is one of the most popularspecies for fishing and breeding in China and the Atlantic coast, so it is of great importance for the protection of genetic resources and the development of new species. In present study, 18 phenotypic traits of ＂Flounder No. 1＂ （ZJ）, a newly breeding species of Japanese flounder, as well as its male （the Korean Japanese flounder stock, KS） and female parents （F0750 family, JX）, were measured. The data were compared by ANOVA and SPSS software. The results showed that there were significant differences （p〈0.05） between ＂flounder No. 1＂ and its parents regarding 6 traits, e. g. body length/ body width, head length/eye diameter, head length/eye spacing, eye diameter/eye spacing, lateral line scales and caudal fin ray which can be used as typical characters for identification of ＂Flounder No. 1＂. In ＂Flounder No. 1＂, 50 % of the traits showed no significant differences （p〉0.05） bcompared to its female parent,while the value decreased to 33.3 % between ＂flounder No. 1＂ and its male parent. A total of 24 microsatellite primers were designed to screen the genetic diversity of KS,JX,ZJ and FJ （reciprocal cross offspring） ,and 143 alleles were identified. For four populations,KS,JX,ZJ and FJ,their mean allelic number （Na） was higher than the effective mean number of alleles （Nac） , the mean heterozygosity was higher than the predicted value. The polymorphism information content （PICo） showed that KS〉JX〉FJ〉ZJ, indicating that the artificial breeding caused the reduction of the genetic heterozygosity. Among the four populations, the genetic deviation index （D） of 24 above mentioned microsatellite loci ranged from-0. 759 7 to 0. 188 4. And in KS,JX,ZJ and FJ,10,16,11 and 17 loci were significantly （p〈 0.05） or extremely （p〈 0.01） deviated from Hardy-Weinberg equilibrium, respectively. The genetic-differentia- tion-index （Fst） of 24 loci ranged from 0. 076 7 to 0. 258 6,with the mean value 0. 1468, which suggests that 14. 68% of the variations result from the interspecies, while 85.32% are intraspecific variations. Furthermore, there was significant difference for Nei＇s genetic distance among four populations. The nearest genetic distance occured between KS and FJ （0. 282 5）,togehter with the highest genetic similarity coefficient （0. 753 9）. While the furthest （0. 420 5） one was found between ZJ and JX with the lowest （0. 656 7） genetic similarity coefficient. In this study, the observation indicated： ＂flounder No. 1＂ has the obvious phenotypic and genetic characteristics, shows a certain degree of genetic differentiation in intraspecies and interspeeies in comparison to its parents and reciprocal cross offspring, which provides the theoretical basis for the germplasm identification of ＂Flounder No. 1＂.