Tatarenkov A, Kwiatowski J, Skarecky D, Barrio E, Ayala F J
Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, CA 92697-2525, USA.
J Mol Evol. 1999 Apr;48(4):445-62. doi: 10.1007/pl00006489.
We have sequenced most of the coding region of the gene Dopa decarboxylase (Ddc) in 24 fruitfly species. The Ddc gene is quite informative about Drosophila phylogeny. Several outstanding issues in Drosophila phylogeny are resolved by analysis of the Ddc sequences alone or in combination with three other genes, Sod, Adh, and Gpdh. The three species groups, melanogaster, obscura, and willistoni, are each monophyletic and all three combined form a monophyletic group, which corresponds to the subgenus Sophophora. The Sophophora subgenus is the sister group to all other Drosophila subgenera (including some named genera, previously considered outside the Drosophila genus, namely, Scaptomyza and Zaprionus, which are therefore downgraded to the category of subgenus). The Hawaiian Drosophila and Scaptomyza are a monophyletic group, which is the sister clade to the virilis and repleta groups of the subgenus Drosophila. The subgenus Drosophila appears to be paraphyletic, although this is not definitely resolved. The two genera Scaptodrosophila and Chymomyza are older than the genus Drosophila. The data favor the hypothesis that Chymomyza is older than Scaptodrosophila, although this issue is not definitely resolved. Molecular evolution is erratic. The rates of nucleotide substitution in 3rd codon position relative to positions 1 + 2 vary from one species lineage to another and from gene to gene.
我们对24种果蝇的多巴脱羧酶（Ddc）基因的大部分编码区进行了测序。Ddc基因对于果蝇系统发育具有很高的信息价值。仅通过对Ddc序列的分析，或结合另外三个基因Sod、Adh和Gpdh进行分析，就解决了果蝇系统发育中的几个突出问题。黑腹果蝇、暗果蝇和威氏果蝇这三个物种组各自都是单系的，并且这三个组合在一起形成一个单系群，该单系群对应于Sophophora亚属。Sophophora亚属是所有其他果蝇亚属（包括一些以前被认为不属于果蝇属的命名属，即Scaptomyza和Zaprionus，因此它们被降级为亚属类别）的姐妹群。夏威夷果蝇和Scaptomyza是一个单系群，它是果蝇亚属中粗壮果蝇和暗黑果蝇组的姐妹进化枝。果蝇亚属似乎是并系的，尽管这一点尚未完全确定。Scaptodrosophila和Chymomyza这两个属比果蝇属更为古老。数据支持Chymomyza比Scaptodrosophila更古老的假说，尽管这个问题尚未完全解决。分子进化是不稳定的。相对于第1和第2位，第3密码子位置的核苷酸替代率在不同的物种谱系之间以及不同基因之间有所不同。
