三疣梭子蟹野生群体同工酶的遗传多态性分析

Isozyme polymorphism in Portunus trituberculatus from wild population

采用聚丙烯酰胺不连续凝胶垂直电泳技术对三疣梭子蟹野生群体的同工酶进行检测。分析了48个样本的11种同工酶在三疣梭子蟹肌肉中的表达情况。11种同工酶(MDH、LDH、ME、SOD、EST、SDH、IDH、ADH、POD、CAT、AAT)共检测出20个基因座位,其中Me-2、Sod-3、Cat-3、Ldh-2共4个座位呈多态(P0.99),多态座位百分数P为20%。平均每个座位的有效等位基因数目Ae为1.230,预期杂合度He为0.094,实际杂合度Ho为0.175。同时还分析了三疣梭子蟹4个多态座位的Hardy-W einberg遗传偏离指数d。与日本绒螯蟹、中华绒螯蟹等相比,三疣梭子蟹野生群体的遗传多样性水平较高,种质资源还处于较好的状态。

Portunus triuberbuculatus is an important economical species in China. In recent years, the wild stocks of P. triuberbuculatus along the coast of China have suffered fatal decrease in their resources due to the overfishing and cultivation. So it is very important to investigate the genetic diversity of P. triuberbuculatus. In October 2005,48 individuals were collected from Zhoushan Gulf. Muscle was collected from each of the samples and stored at -70 ℃ for detection. Muscle was homogenized in mercaptoethanol buffer（0.05% ） at a ratio of 1 ： 3 （ g · mL^- 1 ） with ice-bath and centrifuged at 12 000 r ·min ^-1 for 30 min , 4 ℃. The supematant was used as the isozyme source and electrophoresis was carried out on vertical polyacrylamide gels in Tris-gly buffer system （ TG, pH 8.3 ） at 280 V for approximately 6 h at 4 ℃. The isozymes were analyzed by specific isozyme staining methods. The genetic variation was analyzed in terms of their locus number, structure, alleles, etc. Results showed that there were 20 loci by detecting eleven isozymes in this study. Among the scored loci, 4 loci （Me-2, Sod-3, Cat-3, Ldh-2 ） were polymorphic and the mean proportion of polymorphic loci （P） was 20%. The mean effective number of alleles per locus （Ae ） was 1 . 230, and the mean expected heterozygosity per locus （He） and the mean observed heterozygosity （Ho） were 0. 094 and 0. 175, respectively. In the mean time, the deviation indexes from Hardy-Weinberg equilibrium （d） of four polymorphic loci （ Me-2, Sod-3, Cat-3, Ldh-2 ） were analyzed with 1. 000, 1. 000, 0.818 and 0. 333, respectively. The genetic variability of Portunus trituberculatus was higher than those of Eriochier japonica, Eriochier sinensis.