缢蛏(Sinonovacula constricta)EST-SSR标记与生长性状的相关性分析

CORRELATION OF EST-SSR MARKERS WITH GROWTH TRAITS IN RAZOR CLAM(SINONOVACULA CONSTRICTA)

利用16个微卫星标记对缢蛏F1家系的遗传多样性和标记-性状相关性进行了研究。结果显示,16个SSR位点共检测到39个等位基因,平均等位基因数(Na)和平均有效等位基因数(Ne)分别为2.44和2.09;多态信息含量(PIC)为0.40;平均观测杂合度(Ho)与期望杂合度(He)分别为0.58和0.63,部分位点基因型分布严重偏离孟德尔定律,暗示其可能与适应性基因相连锁,其中YC-8位点附近可能存在杂合不利存活基因。位点YC-96和YC-123与体重呈显著相关(P<0.05),YC-96的BC基因型和YC-123的BB基因型均为体重性状的优势基因型,其对应的壳长、壳宽、壳高和体重4个生长性状表型值都最大,可以作为选育快长性状的候选分子标记;YC-1位点与壳宽呈显著相关(P<0.05),其中BB型是壳宽的优势基因型;YC-93位点与壳宽、壳高呈极显著相关(P<0.01),其中AB型是壳高的优势基因型,BB和BC型是壳宽的优势基因型。对YC-1、YC-93、YC-96和YC-123进行以体重性状为参照的不同基因型组合比较,找到了最优组合(BB/BB(BC)/BC/BB),与4个位点单独分析对应的最优基因型基本完全一致,符合加性作用模型。筛选出的与生长性状相关的标记可为标记辅助选择育种(MAS)提供参考依据。

We analyzed the genetic diversity and screened the markers associated with growth traits using 16 polymorphic microsatellite markers in an F1 family of razor clam Sinonovacula constricta. Thirty-nine alleles were detected, and the average number of alleles and effective number of alleles were 2.44 and 2.09, respectively. The mean polymorphism information content（PIC） was 0.40. The average observed heterozygosity（Ho） and expected heterozygosity（He） were 0.58 and 0.63, respectively. The genotype distribution of partly loci deviated severely from Mendel＇s Laws, suggesting that these loci might link with the adaptive gene, and locus YC-8 may link with heterozygous lethal genes. Loci YC-96 and YC-123 showed significant impact on shell weight（P〈0.05）. Genotypes BC at YC-96 and BB at YC-123 were favorable for shell weight, featuring highest phenotype value in shell weight, length, width, and height, respectively; and therefore can be used as molecular markers in selection breeding. Locus YC-1 showed a significant impact on shell width（P0.05）, in which BB was a dominant genotype of shell width. Locus YC-93 showed an extremely significant effect on shell width and shell height（P〈0.01）, in which AB was the dominant genotype of shell height, and BB and BC were the dominant genotypes of shell width. The best genotype combinations（BB/BB（BC）/BC/BB） for YC-1, YC-93, YC-96 and YC-123 were selected for body weight, which conforms to the additive model.