松江鲈鱼野生群体遗传多样性的RAPD分析和SCAR标记的转化

首先,从294条10个碱基随机引物中,筛选出32条多态性引物,对富春江、黄河、滦河和鸭绿江等4个松江鲈鱼(Trachidermusfasciatus)野生群体共120尾个体进行RAPD分析。结果表明,松江鲈鱼野生群体的遗传多样性较丰富,其主要表现在:①在扩增得到的591个位点中,有515个(87.14%)位点呈现多态性,群体间多态位点比率(P)的大小顺序为:富春江群体89.17%>黄河群体87.99%>鸭绿江群体86.63%>滦河群体83.25%。②松江鲈鱼群体间的Shannon信息指数(IT)和Nei’s遗传多样性指数(HT)分别在0.3393~0.3566和0.2157~0.2279间,滦河群体的值较其他3群体稍低;若作为一个整体,则总的Shannon信息指数(IT)和Nei’s遗传多样性指数(HT)分别为0.3710±0.2153和0.2336±0.1643。③虽然群体间基因流值(Nm)在5.76103～19.84497间,显示各地理群体间存在程度不同的基因交流,但分子方差分析(AMOVA)结果却表明,各群体间存在显著(P<0.05)或极显著(P<0.01)的遗传分化。④聚类分析表明,鸭绿江群体首先与黄河群体聚为一支,再与富春江群体相聚,最后与单独一支的滦河群体聚类,表明鸭绿江、黄河、富春江等3群体间的遗传距离与彼此间的地理距离远近密切相关,而滦河群体与它们的遗传距离较远。其次,从获得的S1225525bp、S1225605bp、S1225841bp、S1345695bp、S1345825bp等5个特异RAPD条带中,成功地由S1225605bp、S1225841bp条带分别转化出SCAR01560bp、SCAR02443bp的SCAR标记。这两个标记的出现频率,在鸭绿江群体最高(96.67%和93.33%)、富春江群体其次(83.33%和90%)、黄河群体再其次(56.67%和66.67%)、滦河群体最低(13.33%和20%)。因此,SCAR01560bp、SCAR02443bp可作为鉴别松江鲈鱼滦河群体与其他3群体的分子标记。

Analysis of genetic diversity in wild populations of Trachidermus fasciatus by RAPD and the transformation of two SCAR markers

Firstly, RAPD was conducted to analyze genetic diversity of Trachidermus fasciatus in the Fuchun River population (FR), Yellow River population (YR), Luan River population (LR), and Yalu River population (YL), with 32 polymorphic 10-bp random primers selected from 294 ones. Thirty wild individuals were detected in each population. The results indicated that the genetic diversity of T . fasciatus was relatively rich. The major results were as the following: 1) Altogether, 591 bands were detected and 515 of them were polymorphic, accounted for 87.14%. The range of proportion of polymorphic loci (P) was: FR(89.17%)>YR(87.99%)>YL(86.63%)>LR(83.25%). 2) The Shannon's information index(I(T)) and Nei's genetic diversity(H(T)) among populations were 0.3393-0.3566 and 0.2157-0.2279, respectively. Compare to other three populations, LR population had relative lower values. If took the populations as a whole, the total Nei's genetic diversity(H(T)) and Shannon's information index(I(T)) was 0.2336±0.1643 and 0.3710±0.2153, respectively. 3) The value of gene flow (N(m) ) (5.76103-19.84497) were high, indicating certain gene exchange existed among the four populations. But the AMOVA results exhibited significantly differentiation (P<0.05 or P<0.01) among the populations. 4) In the UPGMA tree constructed according to genetic distance, YL and YR populations clustered firstly, then with FR population, and finally they joined to LR population. Obviously, the YL, YR and FR populations had relatively close relationship according to their geographic distance, whereas LR population showed clear divergence to the other three populations. Secondly, out of the five special RAPD bands (S(1225)(525 bp), S(1225)(605 bp), S(1225)(841 bp), S(1345)(695 bp) and S(1345)(825 bp)), SCAR maker SCAR01(560 bp) and SCAR02(443 bp) were successfully transformed from S(1255)(605 bp) and S(1255)(841 bp), respectively. After large samples examination of the two markers, we found the highest frequency (96.67% and 93.33%) in the YL population, higher frequency (83.33% and 90%) in the FR population, high frequency (56.67% and 66.67%) in the YR population, and the lowest frequency (13.33% and 20 %) in the LR population. Therefore, SCAR01(560 bp) and SCAR02(443 bp) can be used as special molecular markers for the population identification between LR and other three populations.