牡蛎幼虫光照实验提示复杂遗传背景下基因互作的多样性

为研究光照对牡蛎幼虫生长成活率的影响,使用6组牡蛎幼虫家系,前三组为长牡蛎家系(GG1、GG2、GG3),后三组为长牡蛎与葡萄牙牡蛎杂交家系(GA1、GA2、GA3),其中GG1与GA1母本相同,GG2与GA2母本相同,GG3与GA3母本相同;每个家系分别在6个光照梯度下从1日龄饲养到10日龄,然后测量记录10日龄幼虫在各个光照梯度下的壳高和成活率。结果表明,在各个光照梯度下,牡蛎幼虫的壳高都没有显著差异,长牡蛎幼虫与杂交牡蛎幼虫之间的壳高也都没有显著差异,但长牡蛎幼虫和杂交牡蛎幼虫均在58 lx的光照强度下,表现出最高的成活率,这提示牡蛎育苗生产的前10天应当保持这样的光照强度,而杂交牡蛎幼虫在269 lx和58 lx两个光照梯度下的成活率均极显著的高于长牡蛎幼虫,提示了长牡蛎与葡萄牙牡蛎之间具有亲和性并且其杂交后代存在杂种优势,也在一定程度上支持长牡蛎与葡萄牙牡蛎同属一个物种的假设。而以壳高和成活率作为指标进行聚类分析和主成分分析后发现,长牡蛎3个家系幼虫的表型比较接近,而杂交牡蛎幼虫的表型虽然具有靠近各自同母本长牡蛎幼虫的趋势,但杂交家系之间差异非常大,提示了高杂合度高异质性遗传背景下基因互作的多样性。

THE LIGHT RESPONSES OF OYSTER LARVAE HINTING THE DIVERSITY OF GENE INTERACTION UNDER COMPLICATED GENETIC BACKGROUND

In order to investigate the influence of light on the growth and survival of Pacific oyster Crassostrea gigas larvae and the larvae of Pacific oyster hybridized with Portuguese oyster Crassostrea angulata, Pacific oyster larvae and hybrid larvae were divided into 6 groups, Pacific oyster larvae were recorded as GG1, GG2 and GG3, hybrid larvae were recorded as GA1, GA2 and GA3, GG1 and GA1 were from same one female oyster, GG2 and GA2 were also, and GG3 and GA3 also. Under 6 illumination gradients, 269, 58, 15, 4, 1.5 and 0 lx, the larvae were raised from one-day-old to ten-day-old and their shell height and survival rate were measured. It was found that the was no significant difference among the shell heights of the Pacific oyster larvae or among the hybrid larvae under 6 illumination gradients, and also no significant difference between the Pacific oyster larvae and hybrid larvae, but the survival rate of Pacific oyster larvae or hybrid larvae was the highest under 58 lx among the 6 illumination gradients, suggesting that we should keep the illumination intensity in the 10 days after fertilization. The survival rates of Pacific oyster larvae were higher than those of hybrid larvae at 269 lx and 58 lx, revealing that the hybrid larvae showed the heterosis, supporting the hypothesis that Pacific oyster and Portuguese oyster belonged to the same one species. After the cluster analysis and principal component analysis of the shell height and the survival rate of the 6 families, it was found that the phenotype of 3 Pacific oyster families were similar from each other, that of the Pacific oyster family was somewhat similar to the hybrid family from same one female oyster, but those of hybrid families were very different from each other, hinting that the diversity of gene interaction under the genetic background with high heterozygosity and high heterogenicity.