用Drosophila的基因组数据测试分子进化的中性理论
Justin C Fay1, Gerald J Wyckoff, Chung-I Wu
1Committee on Genetics, University of Chicago, Chicago, Illinois 60637, USA. jcfay@lbl.gov
Nature
|March 5, 2002
概括
积极选择驱动蛋白质进化,而不仅仅是中性过程. 分析显示,适应性进化比以前认为的更快地发生,影响特定的基因.
科学领域:
- 进化生物学是进化的生物学.
- 分子进化的分子进化.
- 人口遗传学 人口遗传学
背景情况:
- 积极选择对蛋白质进化的贡献仍在争论中.
- 中性理论预测多态和分歧的氨基酸 (A) 与同义词 (S) 的比例相等.
- 观察到较高的A/S分歧比率通常归因于正选择,但增加的选择约束是另一种解释.
研究的目的:
- 研究积极选择在蛋白质进化中的作用.
- 要区分积极选择和增加的选择性约束作为A/S比差异的解释.
- 评估基因和物种之间积极选择的流行程度和影响.
主要方法:
- 氨基酸 (A) 与同义词 (S) 多态和分歧比的比较分析.
- 对Drosophila melanogaster和Drosophila simulans的基因特异性进化模式的检查.
- A/S比率的跨物种比较,以评估进化速率.
主要成果:
- 差异的A/S比率是Drosophila的多态性比率的两倍.
- 这种差异仅限于基因的一个子集,它也显示了加速进化的情况.
- 在多种物种中观察到更高的A/S分歧比率,表明广泛的适应性进化.
结论:
- 加速进化的基因特异性模式支持积极选择作为驱动因素,而不是增加选择性约束.
- 适应性进化发生的速度明显高于分子进化的中性理论所预测的速度.
- 积极选择在塑造各种物种蛋白质进化的过程中发挥着重要作用.
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