海湾扇贝混交家系中优先受精以及自然选择压力下杂合子过剩的研究

Investigation of preferential fertilization and heterozygote excess in mixed family of bay scallop (Argopecten irradians)

以中国海湾扇(Argopecten irradians)贝养殖群体为亲本分别构建了5个配对混交的海湾扇贝混交系,通过5对微卫星分子标记为手段对海湾扇贝卵子在同一个体和不同个体精子间的优先受精问题和不同生命阶段的海湾扇贝混交系杂合子比例的变化进行了研究。结果发现在受精后6 h的担轮幼虫期3个混交系中有2个混交系杂合子显著过剩。5个混交系的1d D形幼虫、20d稚贝、40d稚贝、3个月稚贝以及成贝在自然选择压力下杂合子比例逐渐上升,以壳长计算的杂交优势率也呈逐渐上升趋势,并且各个阶段的杂合子比例同杂交优势率的变化成显著正相关。

Five pair-crossed mixed families were constructed by Chinese cultured bay scallop （Argopecten irradians）. Preferential fertilization between self-fertilization and hybridization and the trend of the hybrid proportion in the mixed families were revealed by five microsatellites. Significant heterozygote excess was found in 6-hour-old embryos of two mixed families among total of three mixed families. The hybrid proportions were found rising in 1 d D-shell larval, 20 d spat, 40 d spat, 3 mon spat and adult scallop with natural selection, so did the shell length heterosis. Hybrid proportions were positively related with the shell length heterosis significant among all the life.