在高海拔动物mtDNA中,放松选择比适应性进化更有力的证据
Erik N K Iverson1, Abby Criswell1, Justin C Havird1
1Department of Integrative Biology, the University of Texas at Austin, Austin, TX, United States.
bioRxiv : the preprint server for biology
|February 8, 2024
概括
高海拔物种表现出更快的线粒体DNA进化,但这可能是由于从较小范围的轻松选择,而不是适应. 对非适应性假设的严格测试对于线粒体基因组至关重要.
科学领域:
- 进化生物学 进化生物学
- 分子进化分子进化
- 基因组学就是基因组学.
背景情况:
- 线粒体 (mt) 基因是适应性假设的核心,因为它们在能量代谢中的作用.
- 高海拔环境通常被假设通过积极选择驱动快速的线粒体DNA (mtDNA) 进化.
- 在高海拔mtDNA进化中,放松净化选择与积极选择的作用仍然在很大程度上未经测试.
研究的目的:
- 测试该假设,即高海拔驱动mtDNA的积极选择.
- 调查放松净化选择是否解释了高海拔物种中mtDNA进化速率的升高.
- 检查范围大小,身体大小和度对mtDNA进化速率的影响.
主要方法:
- 计算了线粒体基因组的非同义词与同义词替代率比率 (dN/dS).
- 分析了700多种陆地脊椎动物,淡水鱼类和节肢动物的数据.
- 与高度,度范围限制,范围大小和身体大小相关的dN/dS比.
主要成果:
- 与低海拔的相对亲属相比,高海拔的种群表现出略高的dN/dS比率.
- 较小的范围大小预测了更高的dN/dS比率,这表明选择放松.
- 身体质量与dN/dS正相关,由于有效种群规模较小,支持放松的选择.
结论:
- 高海拔物种中线粒体dN/dS的升高更可能是由于放松的选择 (与较小范围和有效种群大小相关),而不是环境适应.
- 这项研究强调了对线粒体基因组进化的适应性解释进行非适应性假设测试的必要性.
- 结果强调了在对线粒体DNA的进化研究中考虑人口规模和范围动态等因素的重要性.
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