雌核发育银鲫子代中微卫星特异序列分析

雌核发育个体的基因型基本上完全与母本相同,这是源于卵子发生过程中没有经过减数分裂.父本的遗传物质是在随机水平、亚基因组水平或基因组水平参与到子代的遗传重组过程,从而对长期突变积累的雌核发育生物基因组进行补偿,一直是遗传学家关注的问题.本文对雌核发育银鲫特异个体及父母本5个微卫星位点的扩增条带进行了克隆测序,相似性比对结果显示,特异个体所表现的父咎匾霥NA条带,序列结果与父本完全相同或相似(SCM4、SCM9、YJ5),并在某些位点上保留了母本的特异条带(YJ5),而个体本身特异的DNA条带与父母本的相似性均较高(SCM13).同时,所检测到的个体经越冬后查验为雌性个体,进一步进行同源繁育,研究变异条带在繁殖中的命运.连续2代的繁育检测结果表明,融合了父本特异性条带的银鲫个体在繁殖过程中仍行雌核发育的生殖方式,变异来的条带能够传递给子代,进一步证实同源雌核发育银鲫通过小概率两性融合事件丰富银鲫种群的遗传多样性动物学报 53(3):537-544,2007].

Analysis of microsatellite specific sequence in gynogenetic silver crucian carp Carassius autalus gibelio offspring

The genomes of offspring of homologous gynogenetic silver crucian carp (Carassius autalus gibelio Bloch) were screened using microsatellite markers. As a result, a specific individual (F1, No.5) showed much genomic information similar to the paternal fish. Fortunately, this special fish was a female which became sexually mature and produced offspring successfully in the following year. Subsequently, the genotypes of this fish, its parents and offspring were analyzed continually via five microsatellite markers. Meanwhile, the PCR products were cloned and sequenced. A variety of new genomic information was uncovered through DNA sequence alignments. This unique fish showed more genomic similarities with its father as revealed by loci SCM4, SCM9 and YJ5. Likewise, it also inherited some allelic genes from its mother as shown by locus YJ5. Finally it possesses some new genes neither inherited from its father nor its mother as revealed by locus SCM13. In order to detect the stability of alleles characterized to this fish, offspring of two succesive generations were re-screened using the same microsatellite markers. The results revealed that the individuals inherited some paternal alleles still produce descendants with gynogenesis mode, and the variant bands can transfer to offspring steadily. All above indicated silver crucian carp can enrich genetic diversity by amphimixis of small probability event.