近交对马氏珠母贝生长性状、遗传多样性及矿化基因表达的影响

【目的】探讨近交对马氏珠母贝生长性状、遗传结构及矿化基因表达的影响,阐明近交引起子一代性状退化的遗传原理,为贝类品种培育提供参考依据。【方法】以两个黄壳色全同胞家系(M和N)为亲本,按照因子设计构建4个家系组合(F1:M1♀×M1♂;F2:M1♀×N1♂;F3:N1♀×M1♂;F4:N1♀×N1♂),比较4个家系成贝生长性状差异,利用9对SSR引物分析其遗传多样性,并以实时荧光定量PCR检测家系间矿化基因nacrein、pearlin和pif177的表达差异。【结果】4个家系间的平均壳长、平均壳高、平均壳宽、平均体重和平均壳重存在明显差异,且近交家系(F1和F4)的平均壳长、平均壳高、平均壳宽、平均体重和平均壳重均小于杂交家系(F2和F3),其生长性状退化率(ID)为11.7%~29.4%。家系F1、F2、F3和F4的平均观测杂合度分别为0.2525、0.3116、0.3178和0.2752,平均期望杂合度分别为0.3451、0.3822、0.4005和0.3549,平均多态信息含量(PIC)分别为0.4591、0.5389、0.4878和0.4810。杂交家系(F2和F3)矿化基因nacrein、pearlin和pif177的相对表达量均高于近交家系(F1和F4),且4个家系的生长性状平均值与3个矿化基因的相对表达量存在明显正相关。【结论】近交能导致马氏珠母贝生长性状、遗传多样性及矿化基因表达量明显降低,因此制定马氏珠母贝育种方案时应构建合理的交配组合系统,防止因近交导致性状退化与遗传多样性指标降低而影响育种进程。

Effects of inbreeding on growth traits,genetic diversity and biomineraliazation gene expression of Pinctada fuctada martensii

Objective]The effects of inbreeding on growth traits,genetic diversity and biomineraliazation gene expression were evaluated with an aim to clarify genetics principle of trait degradation in first filial generation caused by inbreeding and provide valuable information for breeding shellfish varieties.Method]Two yellow colored full-sib families (M and N) were taken as parents,four family combinations(F1,M1 ♀ ×M1♂;F2,M1 ♀ ×N1♂;F3,N1 ♀ × M1♂;F4,N1 ♀ ×N1♂)were constructed based on factorial design.Growth traits of the shells at adult stage from the four families were compared.Genetic diversity of the four families were analyzed by nine pairs of SSR primers.The expression differences among nacrein,pearlin and pif1 77 genes were evaluated by real-time PCR.Result]There were significant differences on mean shell length,mean shell height,mean shell width,mean total weight and mean shell weight among the four families(P＜0.05).Mean shell length,mean shell height,mean shell width,mean total weight and mean shell weight of inbreeding families (F1 and F4) were smaller than those of hybrid families (F2 and F3),growth trait degradation rate (ID) was 11.7％-29.4％.The observed heterozygosity values of F1,F2,F3 and F4 were 0.2525,0.3116,0.3178 and 0.2752,while the expected heterozygosity values of F1,F2,F3 and F4 were 0.3451,0.3822,0.4005 and 0.3549.Average polymorphism information content(PIC) of F1,F2,F3 and F4 were 0.4591,0.5389,0.4878 and 0.4810.The expressions of biomineraliazation genes nacrein,pearlin and pifl77 in hybrid families(F2 and F3) were higherer than those in inbreeding families(F1 and F4).There was positive correlation between mean growth traits and relative expressions of the three biomineraliazation genes.