牙鲆雌核发育近交系、杂交系的遗传分析与生长比较

Growth comparison and genetic analysis of gynogenetic inbred and hybrid lines of Japanese flounder, Paralichthys olivaceus

建立牙鲆(Paralichthys olivaceus)雌核发育近交系和杂交系,以两性生殖家系作为对照组,对3个群体的遗传特征和生长进行比较。结果表明,雌核发育近交系、杂交系和对照组的等位基因数分别为41、55、78,平均等位基因数为1.7、2.3、3.3,平均观测杂合度为0.419 2、0.654 9、0.916 7,雌核发育杂交系的上述参数明显高于近交系,但低于对照组。3个群体的平均纯合度分别为0.580 7、0.345 1、0.083 3,个体之间的遗传相似度分别为0.831 2、0.826 1、0.672 7,杂交系小于近交系,但明显高于对照组(P<0.05)。在生长方面,雌核发育杂交系比近交系和对照组生长快,差异极显著(P<0.01)。从结果可以看出,雌核发育杂交系具有比近交系高的杂合度,但具有与近交系相似的遗传相似度;生长上比近交系明显快,表现出明显的杂交优势。结论认为雌核发育家系杂交方法可以作为一种育种手段,用于发挥杂交优势和提高遗传相似度。

Gynogenetic inbred （GI） and hybrid lines （GH） of Japanese flounder （Paralichthys olivaceus） were produced by gynogenesis, and their growth and hereditary features were compared. The control group was a cross between a gynogenetic female and normal male. Twenty-four microsatellites markers were selected for the analy- sis. The results showed that 41, 55 and 78 alleles were scored in GI, GH and control group, respectively, with the average number of alleles as 1.7, 2.3 and 3.3. The average observed heterozygosity （Ho） among the 24 analyzed loci in the GH group was 0.654 9, which was higher than that in GI （0.419 2）, but lower than that in the control group （0.916 7）. The average homozygosity was 0.580 7 in GI and 0.345 1 in GH, which were much higher than that in the control group （0.083 3）. The average similarity index among individuals in the GI group （0.831 2） was higher than that of the GH group （0.826 1）, and both were higher than in the control group （0.6727）. The growth rate of the GH group was significantly higher than the GI and control groups （P〈0.01）. According to the result, GH lines have more advantages compared with GI lines and natural mating families（the control group）. Hybridi- zation between gynogenetic individuals could be an essential tool for breeding increased growth rates and to in- crease the genetic similarity of the Japanese flounder.