Sang T K, Chang H Y, Chen C T, Hui C F
Institute of Molecular Biology, Academia Sinica, Taiwan, Republic of China.
Mol Biol Evol. 1994 Mar;11(2):250-60. doi: 10.1093/oxfordjournals.molbev.a040107.
Mitochondrial DNA (mtDNA) sequences that include (a) a part of the cytochrome b gene, (b) two tRNA genes, and (c) a part of the noncoding D-loop region of 31 Anguilla japonica (Japanese eel) and 1 A. marmorata collected from Taiwan, Japan, and mainland China were determined to evaluate the population structure of Japanese eel. Among 30 genotypes identified from the 31 Japanese eel mtDNAs sequenced, there are 58 variable sites, predominantly clustered at the D-loop region. The phylogenetic tree constructed by the unweighted pair-group method with arithmetic mean shows neither significant genealogical branches nor geographic clusters. Furthermore, the sequence-statistics test reveals little, if any, significant genetic differentiation. These results indicate that the 31 Japanese eels might come from a single population. Analysis of sequence variation in mtDNA by using the relationship between the number of segregating sites and the average number of nucleotide differences under the neutral mutation hypothesis reveals that neutral mutation acts as a major factor influencing the evolutionary divergence of the Japanese eel mitochondrial genome sequenced, especially in the noncoding region.
对31条来自日本、台湾和中国大陆的日本鳗鲡（Anguilla japonica）以及1条云纹鳗鲡（A. marmorata）的线粒体DNA（mtDNA）序列进行了测定，这些序列包括：（a）细胞色素b基因的一部分，（b）两个tRNA基因，以及（c）非编码D环区域的一部分，以评估日本鳗鲡的种群结构。在对31条日本鳗鲡mtDNA测序所鉴定出的30种基因型中，有58个可变位点，主要集中在D环区域。通过算术平均的非加权配对组方法构建的系统发育树既没有显示出明显的谱系分支，也没有地理聚类。此外，序列统计检验显示几乎没有显著的遗传分化。这些结果表明，这31条日本鳗鲡可能来自单一群体。在中性突变假说下，通过分析隔离位点数量与平均核苷酸差异数量之间的关系，对mtDNA序列变异进行分析，结果表明中性突变是影响所测序的日本鳗鲡线粒体基因组进化分歧的主要因素，尤其是在非编码区域。
