Tateno Y
National Institute of Genetics, Mishima, Japan.
Jpn J Genet. 1994 Oct;69(5):489-502. doi: 10.1266/jjg.69.489.
Evolution of glutamine synthetase gene is discussed on the results of DNA sequence analysis of the gene. Thirty DNA sequences of various organisms spanning from prokaryotes to eukaryotes were collected from the DNA data banks and translated first, they were aligned next, then evolutionary distances were computed, and molecular phylogeny was finally estimated. The results of the alignment reveal that functionally important regions of glutamine synthetase have been evolutionarily more conserved than the remaining regions. The evolutionary distances computed also show that the rate of synonymous substitution is higher than that of nonsynonymous substitution. These are well in accordance with the neutral theory of molecular evolution. Besides, the molecular phylogeny obtained shows that the origin of glutamine synthetase gene is much earlier than the divergence between eukaryotes and prokaryotes, suggesting that the gene is one of the oldest genes functioning now.
基于谷氨酰胺合成酶基因的DNA序列分析结果，对该基因的进化进行了讨论。从DNA数据库中收集了30种从原核生物到真核生物的不同生物体的DNA序列，首先进行翻译，接着进行比对，然后计算进化距离，最后估计分子系统发育。比对结果显示，谷氨酰胺合成酶功能上重要的区域在进化上比其余区域更为保守。计算得到的进化距离也表明，同义替换率高于非同义替换率。这些结果与分子进化的中性理论完全相符。此外，所得到的分子系统发育表明，谷氨酰胺合成酶基因的起源比真核生物和原核生物的分化要早得多，这表明该基因是目前仍在发挥作用的最古老基因之一。
