六种猫科动物线粒体基因组比较

Comparison of Mitochondrial Genome of Six Felidae

虎(Panthera tigris)、豹(Panthera pardus)、雪豹(Panthera uncia)、云豹(Neofelis nebulosa)、猎豹(Acinonyx jubatus)和家猫(Felis catus)线粒体基因组全序列全长分别为16990、16964、16773、16844、17011和17009bp,包括13个蛋白编码基因、22个tRNA,2个rRNA、一个非编码的控制区(D-loop)以及一个轻链复制起点(OLR),碱基含量A+T大于C+G。在蛋白编码基因中,AT偏向性在密码子的第二位点更加明显,这与大多数哺乳动物第三位点AT偏向性较高明显不同。蛋白质基因在密码子的使用上,ATG为多数基因的起始密码子,TAA为多数基因的终止密码子。预测的tRNA二级结构显示,除tRNASer(AGY)基因缺失"DHU"臂外,其余的tRNA基因序列都可以折叠成典型的"三叶草结构"。控制区位于tRNAPro和tRNAPhe之间,控制区结构为高变Ⅰ区、中央保守Ⅱ区和保守序列Ⅲ区三个结构域。

The entire mitochondrial genome of Panthera tigris, Panthera pardus, Panthera uncia, Neofelis nebulosa , Acinonyx jubatus and Fells catus were 16990,16964,16773,16844,17011 and 17009 bp in length with A＋T 〉C＋G. Each mitochondrial DNA genomes included 13 protein--coding genes, 22 tRNA, two rRNA, one OLR and one control region. AT base preference was unique to the second site of the codon in protein--coding region which obviously differentiated from that of other mammals. Most protein coding genes of the mitochondrial genome started with ATG codon. For terminate codon usage, most of genes terminate with codons TAA. The secondary structures of 22 tRNA were predic- ted, tRNA can form typical cloverleaf--shaped structure except tRNA^Ser（AGY）with an absence of ＂DHU＂ arm. The control region located between tRNA^Pro and tRNA^Phe with three structure domains.