Dai Ji-gang, Min Jia-xin, Xiao Ying-bin, Lei Xia, Shen Wen-hao, Wei Hong
Department of Thoracic Surgery, Xinqiao Hospital, The Third Military Medical University, Chongqing 400037, China.
J Exp Biol. 2005 Dec;208(Pt 23):4445-50. doi: 10.1242/jeb.01920.
Mitochondrial DNA (mtDNA), which exhibits a maternal inheritance and a high rate of evolution, has been widely used as a genetic marker when analyzing maternal lineage and inferring phylogenetic relationships among species. In this study, mtDNA variations among four classical (BALB/c, C3H, C57BL/6J and DBA/2) and three Chinese (TA2, 615 and T739) inbred strains of laboratory mice were analyzed by PCR-RFLP (polymerase chain reaction coupled with restriction fragment length polymorphism) and PCR-SSCP (polymerase chain reaction coupled with single-stranded conformational polymorphism) techniques. PCR-RFLP analyses on 46 restriction sites revealed no variations in mtDNA D-loop (displacement loop), tRNA(Met+Glu+Ile) and ND3 (NADH dehydrogenase subunit 3) gene fragments in these strains. Furthermore, PCR-SSCP analyses demonstrated no variations in D-loop 5' and 3' end fragments in them. In view of enormous polymorphisms in mtDNA among mice and dramatic differences in nuclear genomes of these seven strains, our findings were surprising. However, in light of the maternal inheritance of mtDNA, the results indicate that the three Chinese strains, including TA2, T739 and 615, and the four classical strains, share a common maternal lineage.
线粒体DNA（mtDNA）具有母系遗传和高进化速率的特点，在分析母系谱系和推断物种间的系统发育关系时，已被广泛用作遗传标记。在本研究中，采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）和聚合酶链反应-单链构象多态性（PCR-SSCP）技术，分析了四种经典近交系（BALB/c、C3H、C57BL/6J和DBA/2）和三种中国近交系（TA2、615和T739）实验小鼠的mtDNA变异。对46个限制性位点进行的PCR-RFLP分析显示，这些品系的mtDNA D环（置换环）、tRNA(Met+Glu+Ile)和ND3（NADH脱氢酶亚基3）基因片段没有变异。此外，PCR-SSCP分析表明，它们的D环5'和3'末端片段也没有变异。鉴于小鼠mtDNA存在大量多态性，且这七个品系的核基因组存在显著差异，我们的研究结果令人惊讶。然而，鉴于mtDNA的母系遗传，结果表明包括TA2、T739和615在内的三种中国品系与四种经典品系具有共同的母系谱系。
