科技发展、文化进步是否已使人类摆脱“自然选择”的法则？加拿大魁北克大学蒙特利尔分校研究人员10月7日说，人类仍在进化。
“通常认为，现代文明与技术进步已经使人类停止进化，弱化了自然选择的规律，”引领这项研究的埃曼努尔·米洛特说，“但我们的研究发现，人类仍在进化。”
研究人员在魁北克市东北80公里的奥库德岛发现了人类进化的证据。奥库德岛居民种族结构单一，教育水平相近，信奉同种宗教，是数据分析理想样本。
研究人员查阅当地教堂1799年到1940年的注册记录，发现在这140年间，妇女生育第一胎的年龄由大约26岁降至22岁。
排除社会、环境等影响因素，研究人员发现，生育第一胎早的女性更受“大自然青睐”。其他样本研究也得出相同结论。
通常理解中，妇女营养条件改善，成熟更早，或许是生育第一胎年龄降低的原因。但研究人员注意到，如果是营养条件改善促使育龄提前，那么“婴幼儿存活率”这一直接关乎营养条件的指标应当发生变化，但实地发现，婴幼儿存活率并未发生大的改变，由此可排除营养条件等因素对当地头胎育龄提前的影响。
米洛特说，调查发现，头胎育龄的变化“更多由基因因素引发”。
“仅仅在几代人间便可探测到人类的微小进化，”米洛特说。
这项研究结果将发表于11日出版的加拿大《国家科学院学报》。
相关英文论文摘要：
Evidence for evolution in response to natural selection in a contemporary human population
It is often claimed that modern humans have stopped evolving because cultural and technological advancements have annihilated natural selection. In contrast, recent studies show that selection can be strong in contemporary populations. However, detecting a response to selection is particularly challenging; previous evidence from wild animals has been criticized for both applying anticonservative statistical tests and failing to consider random genetic drift. Here we study life-history variation in an insular preindustrial French-Canadian population and apply a recently proposed conservative approach to testing microevolutionary responses to selection. As reported for other such societies, natural selection favored an earlier age at first reproduction (AFR) among women. AFR was also highly heritable and genetically correlated to fitness, predicting a microevolutionary change toward earlier reproduction. In agreement with this prediction, AFR declined from about 26–22 y over a 140-y period. Crucially, we uncovered a substantial change in the breeding values for this trait, indicating that the change in AFR largely occurred at the genetic level. Moreover, the genetic trend was higher than expected under the effect of random genetic drift alone. Our results show that microevolution can be detectable over relatively few generations in humans and underscore the need for studies of human demography and reproductive ecology to consider the role of evolutionary processes.
英文论文链接：https://www.pnas.org/content/early/2011/09/28/1104210108.abstract
