从ATPase8-6基因研究杂交多倍体鱼线粒体母性遗传

异源四倍体鲫鲤是世界上首例人工培育的两性可育并形成群体的且能自然繁殖的四倍体鱼。本文采用质粒克隆测序法测定了红鲫、异源四倍体鲫鲤、三倍体湘云鲫和三倍体湘云鲤的ATPase8和ATPase6基因全序列 ,结合鲤鱼、日本白鲫和斑马鱼的同源序列 ,对不同倍性水平鲤科鱼类的ATPase8和ATPase6基因进行了比较 ,分析了碱基组成、变异情况以及核苷酸和氨基酸序列差异。红鲫、鲤鱼、异源四倍体鲫鲤、日本白鲫、三倍体湘云鲫和三倍体湘云鲤之间的序列差异为 0 0 % - 1 3 4 % ,它们与外群斑马鱼之间的序列差异为 2 7 9% -31 0 %。用MEGA软件中的MP法、ME法、NJ法和UPGMA法构建分子系统树 ,得到了相似的拓扑结构。结果分析表明 ,人工杂交多倍体异源四倍体鲫鲤、三倍体湘云鲫和三倍体湘云鲤在线粒体ATPase8和ATPase6基因上具有严格的母性遗传特征。值得注意的是 ,异源四倍体鲫鲤经过 1 1代的繁育后 ,与其原始母本红鲫仍然保持了非常高的同源性 ,说明了新的异源四倍体基因库在线粒体ATPase8和ATPase6基因上拥有稳定的遗传特性。对不同倍性鲤科鱼类线粒体ATPase8和ATPase6基因的研究表明 ,ATPase8和ATPase6基因是杂交鱼后代遗传变异研究的一个很好的分子标记

Evidence for maternal inheritance of mitochondrial DNA in polyploid fish of crosses by ATPase8 and ATPase6 genes

The entire sequences of the mitochondrial ATPase8 and ATPase6 genes for the red crucian carp, allotetraploid fish, triploid crucian carp, and triploid common carp were isolated and completely sequenced. The nucleotide divergences of the ATPase8 and ATPase6 genes were 0 0% to 13 4% among ingroup samples (red crucian carp, common carp, allotetraploid fish, Japanese crucian carp, triploid crucian carp, and triploid common carp) and 27 9% to 31 0% between the ingroup samples and outgroup zebrafish. Most nucleotide substitutions among all samples occurred at the third codon positions of the ATPase8 and ATPase6 genes and were silent mutations. Phylogenetic trees showing three clusters were constructed with the ATPase8 and ATPase6 gene sequence data for all samples. The first cluster contained triploid common carp and diploid common carp; the second cluster contained triploid crucian carp and diploid Japanese crucian carp; and the third cluster contained allotetraploid fish and diploid red crucian carp. This finding indicated that mitochondrial ATPase8 and ATPase6 genes of the artificial polyploid fish including the allotetraploid fish, triploid crucian carp, and triploid common carp were inherited maternally. It was noticeable that after eleven generations from F 1 to F 11 hybrids, the F 11 allotetraploid fish still kept the high homology to the female parent red crucian carp in the ATPase8 and ATPase6 genes. The high homology of F 11 tetraploid to the female parent red crucian carp also indicated that the F 11 allotetraploid fish possessed the stable inheritable characteristic. The analysis and elucidation of the variation of the ATPase8 and ATPase6 DNA in different cyprinids proved that ATPase8 and ATPase6 genes were the useful genetic markers to monitor the variations in the progeny of the crosses .