分子钟假说与化石记录  

HYPOTHESIS OF MOLECULAR CLOCK AND FOSSIL RECORDA REVIEW

作　　者：唐先华[1] 赖旭龙[1] 钟扬[2] 李涛[1] 杨淑娟[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]复旦大学生物多样性研究所,上海200433

出　　处：《地学前缘》2002年第2期465-474,共10页Earth Science Frontiers

基　　金：国家自然科学基金海外合作基金资助项目 ( 4 0 0 2 82 0 1)

摘　　要：进化是整个生命科学研究的核心和灵魂 ,而早期的生命演化在生物进化过程中具有重要地位 ,是科学界研究的前沿和热点问题。基于生物的遗传距离所建立的分子进化速率 ,可用于进一步推测不同生物类群在进化历史上的分歧时间。这一间接时间数据可与化石记录所反映的直接数据进行比较。分子钟研究为探究早期生命演化提供了一个新的途径 ,不仅可用来对基于化石记录的传统结论加以验证 ,同时对于化石记录不完整的生物类群起源历史的推测具有特殊意义。然而 ,利用分子钟方法所得出的不同门类起源时间总是早于化石记录 ,因此分子钟与化石记录的矛盾仍十分突出。文中综述了基于化石证据研究后生动物起源、寒武纪生命大爆发及被子植物起源等早期生命演化的研究进展 ,介绍并分析、讨论了分子钟方法及利用分子钟研究早期生命起源时间问题及其与化石记录间的矛盾 。Evolution is the core of the life science. The evolution of early life plays an important role during the organism evolution, and it becomes the frontier and hot topic of the scientific research. Based on genetic distances, molecular evolution rates established by the hypothesis of molecular clock can be used to deduce the origin or divergence time of different organism taxa. This indirect data can be compared with the direct data obtained from fossil records. Molecular clock provides new approach for studying of the evolution of early life in view of molecular evolution. It not only can be used to test the conclusions inferred from fossil records, but also can be used to deduce the evolutionary history of the taxa without completed fossil record. However, the origin time inferred by molecular clock is always earlier than that by the fossil record. This approach is still controversial. This paper reviews the progresses of the study of early life evolution including the origin of Metazoan, Cambrian explosion and origin of Angiosperm based on new finds of fossil record, introduces the molecular clock hypothesis and its application to the research on the origin time of early life, and indicates the conflicts between molecular clock and fossil record as well. Authors also consider that ancient DNA data can be used to modify the molecular clock hypothesis.

关 键 词：分子钟假说 化石记录 早期生命演化 古DNA 分子进化速度 

分 类 号：Q91[天文地球—古生物学与地层学] Q7[生物学—古生物学]