凡纳滨对虾(Litopenaeus vannamei)不同生长阶段体质量的遗传变化

GENETIC VARIATION IN BODY WEIGHT OF LITOPENAEUS VANNAMEI IN DIFFERENT GROWTH STAGES

采用条件数量性状加性-显性遗传模型(AD),分析凡纳滨对虾(Litopenaeus vannamei)仔虾(S1)、幼虾(S2)、成虾(S3)、亲虾(S4)阶段体质量性状的动态遗传效应。结果显示:仔虾阶段和幼虾阶段体质量非条件加性方差几乎为0,成虾阶段和亲虾阶段分别8.856和24.114,条件遗传方差分别为0.075676±0.0101、0.270944±0.0342、14.013±0.4847、25.68467±1.3631且均达到极显著水平(P<0.01),非条件加性方差占表型方差的比例分别为8.062%、0.9765%、11.308%和24.636%,条件加性方差所占比例为8.132%、1.203%、36.122%和29.581%;仔虾、幼虾、成虾阶段控制凡纳滨对虾体质量性状的累加基因效应中显性效应分别占88.666%、98.664%、85.050%,亲虾阶段控制凡纳滨对虾体质量性状的累加基因效应中加性效应占遗传方差总量的60.438%;0|S1和S2|S1期间控制体质量表现的基因效应是以净显性效应为主,分别为其遗传方差总量88.666%和98.156%;S2|S3和S3|S4期间以净加性效应为主,分别为其遗传方差总量的70.386%和88.565%。结果表明,随着凡纳滨对虾生长发育进行控制体质量性状的加性效应表达呈增加趋势;在凡纳滨对虾养成阶段体质量性状主要以显性效应为主,暗示选择性杂交能有效改良其体质量性状。

We studied the genetic variation in body weight of Litopenaeus vannamei in different growth stages from postlarvae（S1）, juvenile（S2）, adult（S3）, to broodstock（S4）. Additive and dominant genetic mode and statistical methods were applied. The results show that the components of unconditional additive variance were nearly 0 in S1 and S2, and 8.856 and 24.14 in S3 and S4, respectively. The conditional addition variance was 0.075676±0.0101, 0.270944±0.0342, 14.013±0.4847, and 5.68467±1.3631 all at highly significant level（P〈0.01） in S1 to S4, respectively. The contribution of the unconditional additive variance to phenotypic variance was 8.06%, 0.98%, 11.31%, and 24.64%, and that of the conditional one was 8.13%, 1.20%, 36.12%, and 29.58% in S1 to S4, respectively. Of the accumulated effect, the dominant effect took 88.67%, 98.66%, and 85.05% in stages S1 to S3, respectively, but in S4, additive gene effect contributed for 60.44%. In S1 and S2, the net dominant effect controlled the body weight trait by taking 88.67% and 98.16%, while in S3 and S4, net additive effect played the role accounting for 70.39% and 88.57%, respectively. Therefore, in early stages of L. vannamei grow-up, the additive effect of body weight trait was the main effect and expressed increasingly, while in late stages, the dominant effects overtook, implying that selective hybridization can effectively improve the body weight trait of the shrimp.