驯食配合饲料的大口黑鲈3个选育世代的遗传多样性分析

为了检测驯食配合饲料的大口黑鲈(Micropterus salmoides)3个选育世代群体遗传多样性水平变化,利用微卫星标记技术对驯食配合饲料大口黑鲈选育基础群体(Sp0)和第二、三和四代选育群体(Sp2、Sp3和Sp4)共240尾样品进行检测。结果显示,18个微卫星位点共获得44个等位基因。Sp0、Sp2、Sp3和Sp4的平均观测杂合度(H_o)分别为0.4895、0.4802、0.4579和0.4206,平均期望杂合度(H_e)分别为0.4615、0.4454、0.4621和0.3916,平均多态信息含量(PIC)分别为0.3791、0.3659、0.3764和0.3257。4个群体间的配对比较群体间遗传分化指数(F_(st))值在0.01612～0.16162之间、遗传距离(D_a)在0.0249～0.1434之间。遗传变异来源(AMOVA)分析显示,只有8.38%的变异来自于群体间,其余遗传变异均来自于个体间。研究表明,经连续多代选育之后,易驯食配合饲料的快长大口黑鲈选育群体具有中度遗传多样性,具备选育潜力,可继续进行选育。

Analysis on Genetic Diversity of Three Breeding Populations of Largemouth Bass Using Formulated Feeds

Largemouth bass (Micropterus salmoides) is a very important fish in commercial farming. As it is a carnivorous teleost, a large amount of forage fish and fish meal were used as food for largemouth bass every year. Residual forage fish and fish meal not only increase the costs of largemouth bass aquaculture, but also seriously pollute water bodies and farm lands. In order to reduce farming costs and protect the natural environment, selective breeding suitable for formulated feeds was carried out. In 2012, our research team selected the breeding population contain Youlu No.1 largemouth bass and introduced north largemouth bass. The genetic structure of largemouth bass breeding population was analyzed based on microsatellite DNA markers. A total of 240 individuals, from the foundation population (Sp0), the second generation group (Sp2), the third generation group (Sp3), and the fourth generation group (Sp4) (60 individuals per population) were assayed with 18 microsatellites. The results showed that a total of 44 alleles were identified, the numbers of alleles (Na) were 1~4 in four selected populations, respectively. The observed heterozygosity (Ho) of Sp0, Sp2, Sp3 and Sp4 was 0.4895, 0.4802, 0.4579 and 0.4206, respectively; the expected heterozygosity (He) was 0.4615, 0.4454, 0.4621 and 0.3916, respectively; the polymorphism information content (PIC) of Sp0, Sp2, Sp3 and Sp4 was 0.3791, 0.3659, 0.3764 and 0.3257, respectively. The F-statistics (Fst) value is between 0.01612 and 0.16162, and the genetic distance (Da) is between 0.0249 and 0.1434. Partitioning of the genetic variation revealed that only 8.38% genetic variation was among the populations, and the other genetic variation was within the populations. The results showed that the artificially selected population using formulated feeds showed moderate genetic diversity, and still had great potential for future selective breeding.