二倍体泥鳅线粒体细胞色素b基因的序列分析

对二倍体泥鳅的线粒体细胞色素b基因进行PCR扩增和正反测序，在5个个体中均得到序列一致的细胞色素b基因片断，长度为1140bp，A、T、G、C含量分别为313（28％）、358（31％）、170（15％）、300（26％），A＋T〉C＋G，与其他水生动物相同基因片段碱基序列含量相似，该基因中密码子第1位核苷酸中4种碱基组成较为均衡；第2位核苷酸中T的使用率较高，为33．4％，G的使用率较低，为17．1％；密码子第3位A的使用率高，为34．2％，而G的使用率较低，仅为7．9％；由泥鳅细胞色素b基因片断推导出对应的氨基酸序列，在氨基酸序列中Leu占11．％，远高于其他氨基酸。

Sequence Analysis of Coding Region in Mitochondrial Cytochrome b Gene from Diploid Oriental Weatherfish Misgurnus anguillicaudatus

Mitochondrial DNA cytochrome b gene was amplified by PCR and sequenced in two directions in diploid oriental weatherfish Misgurnus anguillicaudatus.The results showed that there were no differences in sequence among the five samples.The target fragments' sequence was 1140 bp in length and had 313(28%),358(31%),170(15%),300(26%) of A,T,G,and C,respectively,A T>C G,which were similar to the sequences in other aquatic animals.The first positions of codons had even usage in 4 nucleotides;the second positions of the codons in the gene havd high content of T(33.4%) but low content of G(17.1%);34.2% content of A and 7.9% content of G were found in the third positions.The corresponding amino acid sequence was deduced that the percentage of Leu used in cytb gene was 11.92% in this sequence,much higher than any other amino acids.This study provided the basic data of nucleotide acid sequence for the research of seed quality and provides an opportunity to research the evolution between diploid weatherfish and allotetraploid weatherfish.