Morgan-Richards M
Department of Zoology, University of Otago, Dunedin, New Zealand.
Cytogenet Genome Res. 2002;96(1-4):217-22. doi: 10.1159/000063042.
The weta Hemideina crassidens has two chromosomal races that differ by two centric fusions or fissions. The mitochondrial DNA of weta from both chromosomal races and a sister species were sequenced for a 750-bp region of the gene coding for cytochrome oxidase I. The average pairwise genetic distance among the 15 (XO)-chromosome race weta was almost four times greater than the average distance among the 19 (XO)-chromosome race weta. The weta from the 19-chromosome race formed a well-supported monophyletic clade in all shortest maximum parsimony trees. Maximum likelihood and neighbor-joining trees suggested that the 15-chromosome karyotype was paraphyletic with respect to the 19-chromosome karyotype, but this was not supported by maximum parsimony analyses. Although phylogenetic analysis could not exclude chromosome fusion as the rearrangement responsible for the karyotype differentiation, the level of sequence variation and pattern of distribution appear to implicate fission as the more likely event.
厚齿湿婆蟋有两个染色体族，它们因两个着丝粒融合或裂变而不同。对来自两个染色体族以及一个姐妹物种的湿婆蟋的线粒体DNA进行了测序，针对细胞色素氧化酶I编码基因的一个750碱基对区域。15条（XO）染色体族湿婆蟋之间的平均成对遗传距离几乎是19条（XO）染色体族湿婆蟋之间平均距离的四倍。在所有最短最大简约树中，19条染色体族的湿婆蟋形成了一个得到充分支持的单系类群。最大似然法和邻接法树表明，15条染色体核型相对于19条染色体核型是并系的，但最大简约分析并不支持这一点。尽管系统发育分析不能排除染色体融合是导致核型分化的重排方式，但序列变异水平和分布模式似乎表明裂变是更可能发生的事件。
