Simmons R B, Weller S J
Department of Entomology, University of Minnesota, 219 Hodson Hall, 1980 Folwell Avenue, St. Paul, Minnesota 55108-6125, USA.
Mol Phylogenet Evol. 2001 Aug;20(2):196-210. doi: 10.1006/mpev.2001.0958.
Cytochrome b (cyt-b) is widely used in molecular phylogenetic studies of vertebrate, but not invertebrate, taxa. To determine whether this situation is an historical accident or reflects the utility of cyt-b, we compared the abilities of cyt-b, COI, and one nuclear ribosomal gene region (D1 of 28S) to recover intergeneric relationships within the tiger moth tribes Ctenuchini and Euchromiini. Additionally, we compared the rate of sequence and amino acid evolution of cyt-b across insects. Cytochrome b had the same level of sequence variation and A/T bias as COI, but was less useful for recovering intergeneric relationships. The total evidence tree casts doubt on the traditional taxonomy of the group. For the class Insecta, we found that functional conservation of amino acids occurs for the same regions as those found in vertebrates with the exception of Mallophaga (lice). Lice have an accelerated rate of nonsynonymous substitutions. Accelerated rate of cyt-b nucleotide and amino acid evolution in Apidae (bees) may be correlated with increased metabolic rates associated with facultative endothermy (= heterothermy).
细胞色素b（cyt-b）广泛应用于脊椎动物而非无脊椎动物类群的分子系统发育研究。为了确定这种情况是历史偶然还是反映了cyt-b的实用性，我们比较了cyt-b、细胞色素氧化酶亚基I（COI）和一个核糖体基因区域（28S的D1）在恢复灯蛾族Ctenuchini和Euchromiini属间关系方面的能力。此外，我们还比较了昆虫中cyt-b的序列和氨基酸进化速率。细胞色素b与COI具有相同水平的序列变异和A/T偏向，但在恢复属间关系方面作用较小。综合证据树对该类群的传统分类法提出了质疑。对于昆虫纲，我们发现除食毛目（虱子）外，氨基酸的功能保守区域与脊椎动物中的相同。虱子具有加速的非同义替换率。蜜蜂科（蜜蜂）中cyt-b核苷酸和氨基酸的加速进化速率可能与兼性体温调节（=异温性）相关的代谢率增加有关。
