时间：2024年6月27日（星期四）10:00-12:00
讲者：张建之教授 美国密歇根大学
主题：Quasi-neutral molecular evolution
内容提要：
The neutral theory of molecular evolution asserts that most nonsynonymous substitutions are selectively neutral. However, deep mutational scanning data reveal that typically >1% of nonsynonymous mutations are beneficial, predicting that >99% of nonsynonymous substitutions are adaptive. We propose that frequent environmental changes and mutational antagonistic pleiotropy across environments render the bulk of beneficial mutations seen at one time deleterious soon after, hindering their fixations. Consequently, despite the occurrence of adaptive tracking-continuous adaptation to a changing environment fueled by beneficial mutations, neutral substitutions prevail. This quasi-neutral model reconciles the prevalence of beneficial mutations with patterns of neutral evolution, is supported by population genetics simulations and evolution experiments, and has implications for the fitness effects of genetic polymorphisms and the tempo and mode of evolution.
讲者简介：
张建之，1998年获得美国宾夕法尼亚州立大学遗传学博士学位，现任美国密歇根大学生态学与演化生物学系Marshall W. Nirenberg讲席教授，是分子与基因组演化领域著名学者，美国科学促进会会士（AAAS Fellow）。张建之教授是基因组学、进化系统生物学领域的国际著名学者，在自然选择、基因重复、适合度图谱、基因多效性、遗传相互作用、突变率、转录组进化、同义密码子使用等领域做出了一系列开创性的工作，目前在Nature、Science、Genome Research等国际权威刊物发表论文200多篇，被引用两万五千余次。曾任国际分子生物学与演化学会主席，多年来担任Molecular Biology and Evolution、Genome Biology and Evolution、PLOS Genetics等期刊的副主编或高级编委。
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