简单的DNA重复的固有不稳定性形成了重复长度的进化稳定分布
Ryan J McGinty1, Daniel J Balick1, Sergei M Mirkin2
1Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA.
Nature communications
|December 9, 2025
概括
简单的双重重复 (STR) 在哺乳动物中显示一致的长度分布. 在基因组中常见的长重复,源于突变动态,而不是选择,可能导致重复扩张障碍.
科学领域:
- 基因组学就是基因组学.
- 进化生物学 进化生物学
- 分子生物学分子生物学
背景情况:
- 简单的双重重复 (STR) 在哺乳动物基因组中很普遍.
- 塑造STR长度分布的进化力量尚未完全理解.
- 较长的STR与各种遗传疾病有关.
研究的目的:
- 分析STR长度在人类和300多种哺乳动物基因组中的分布.
- 调查调控STR长度的突变动态和进化过程.
- 确定选择与突变在塑造STR分布中的作用.
主要方法:
- 使用端粒对端粒的参考,组装STR长度分布.
- 分析了300多个哺乳动物基因组.
- 对突变速率 (扩张,收缩,中断) 和每代动态的定量建模.
- 评估塑造STR长度分布的长期行为.
主要成果:
- 在哺乳动物进化过程中,STR长度分布形状的显著一致性.
- 所有分析的基因组都显示出多余的长STRs,可能与重复扩张障碍有关.
- 简短的重复序列是随机替换的结果.
- 较长的STR (>10 nt) 通过扩张,收缩和中断突变的动态平衡来维持.
- 这些突变过程足以解释长STRs的丰富性,而无需调用自然选择.
结论:
- STR长度分布是由突变动力学塑造的,而不是自然选择.
- 扩张,收缩和中断突变的平衡解释了长期STRs的持久性.
- 了解这些突变机制对于了解基因组忠实性和重复不稳定性障碍至关重要.
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