露螽属四种昆虫Cyt b基因序列及系统进化研究(直翅目,露螽科)

研究了露螽属4种昆虫线粒体细胞色素b基因(Cyt b)的部分序列,分析了核苷酸序列组成与变异及氨基酸差异.在得到的432bp序列中,A T约占66.9%,其中102个核苷酸位点发生了变异(约23.8%),从每个氨基酸密码子来看,第3位点的A T含量较高,为79.7%.Cyt b基因编码的144个氨基酸由19种氨基酸组成,有12个发生了变异,占氨基酸总数的8.33%,其中亮氨酸(Leu)与苯丙氨酸(Phe)的含量较高,谷氨酸(Glu)、赖氨酸(Lys)与精氨酸(Arg)的含量较低,无半胱氨酸(Cys).以日本纺织娘和中华螽斯为外群构建的NJ分子系统树显示,镰尾露螽与齿尾露螽是分化较晚的类群,其次是瘦露螽,黑角露螽是分化较早的类群.

A MOLECULAR PHYLOGENY OF FOUR SPECIES OF GENUS PHANEROPTERA BASED ON MITOCHONDRIAL CYTOCHROME b SEQUENCES (ORTHOPTERA,PHANEROPTERIDAE)

The mtDNA Cyt b sequences (432bp) were analyzed in 4 species of the genus Phaneroptera, the base substitutions and divergence of nucleotide were calculated. The molecular phylogenetic tree was constructed with Neighbor-Joining method using Tettigonia chinensis and Mecopoda niponensis as outgroups. The confidence of nodes in the trees was evaluated by Bootstrap value (1000 replicates). In the target sequences, the percent of A+T was about 66.9%, and 102 nucleotide sites were variable (about 23.8%), 12 sites resulted in the variation of amino acids (about 8.33%). There is no Cysteine in the 144 amino acids with more bias in Leucine and Phenylalanine. The percent of A+T in the third sites of codon was higher than the other two sites. The NJ trees indicated that Ph.falcate and Ph.myllocerca were the advanced group, Ph.nigroantennata was the primitive group.