Kocher T D, Conroy J A, McKaye K R, Stauffer J R, Lockwood S F
Department of Zoology, University of New Hampshire, Durham 03824, USA.
Mol Phylogenet Evol. 1995 Dec;4(4):420-32. doi: 10.1006/mpev.1995.1039.
The complete sequence (1047 bp) of the mitochondrially encoded ND2 gene was obtained from 31 species of cichlid fishes to investigate the evolutionary history of the species flocks of the East African lakes. The observed pattern of nucleotide substitution in this sequence is typical of mitochondrial genes, showing a high transition bias and rapid mutational saturation, especially at codon positions where base frequencies are unequal. The base composition of the third position of codons is heterogeneous among species, suggesting frequent shifts in the pattern of substitution. Phylogenetic analysis of the sequences shows that the mtDNA variation in Lake Malawi cichlids is nested monophyletically within the range of variation shown by Tanganyikan cichlids. The closest Tanganyikan relatives of the Malawi flock are members of the tribe Tropheini. Classifications based on morphology are generally supported by the mtDNA data, with some significant exceptions in the Tropheini and Lamprologini. Because of an apparently rapid radiation of the Tanganyikan lineages, it is difficult to assess the basal topology of the Tanganyikan radiation at this time. Divergences among tribes are consistent with an intralacustrine radiation within the past 10 million years.
从31种丽鱼科鱼类中获得了线粒体编码的ND2基因的完整序列（1047碱基对），以研究东非湖泊物种群的进化历史。该序列中观察到的核苷酸替换模式是线粒体基因的典型模式，显示出较高的转换偏向和快速的突变饱和，特别是在碱基频率不相等的密码子位置。密码子第三位的碱基组成在物种间是异质的，表明替换模式频繁变化。对这些序列的系统发育分析表明，马拉维湖丽鱼科鱼类的线粒体DNA变异单系嵌套在坦噶尼喀湖丽鱼科鱼类所显示的变异范围内。马拉维湖鱼类群在坦噶尼喀湖最亲近的亲属是Tropheini部落的成员。基于形态学的分类通常得到线粒体DNA数据的支持，但在Tropheini和Lamprologini部落中有一些显著例外。由于坦噶尼喀湖谱系明显快速辐射，目前难以评估坦噶尼喀湖辐射的基部拓扑结构。部落间的分歧与过去1000万年内在湖泊内的辐射一致。
