MANS PLACE IN HOMINOIDEA AS INFERRED FROM MOLECULAR CLOCKS OF DNA
MANS PLACE IN HOMINOIDEA AS INFERRED FROM MOLECULAR CLOCKS OF DNA
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DOI：
10.1007/bf02111287
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发表时间：
1987-01-01
影响因子：
3.9
通讯作者：
YANO, TA
中科院分区：
文献类型：
--
作者：
HASEGAWA, M;KISHINO, H;YANO, TA
通过DNA序列的分子钟分析估计了灵长类动物的分化日期。通过将卡他鼻族和扁鼻族的分歧时间定为3800万年前，校准了η-珠蛋白假基因的分子钟。该时钟给出的恒河猴、猩猩、大猩猩和黑猩猩与人类的分界线分别为25.3±2.4、11.9±1.7、5.9±1.2和4.9±1.2百万年前（±为标准误差）。在以稳健的方式确定估计值的置信区间时，使用了bootstrap方法。恒河猴、猩猩、大猩猩和黑猩猩的95%置信区间分别为20.5-29.5、9.0-14.8、4.1-7.8和3.1-7.0百万年前。通过对原猴亚目-人类总科分裂的分子钟测年，推测在灵长类进化的早期，η-珠蛋白基因的进化速率很高，而在人类总科进化的后期，η-珠蛋白基因的进化速率降低。通过自举抽样的相对比率检验，提出了人总科的比率比猕猴总科进一步下降（超过10%）的可能性。因此，上述关于人总科分裂的年代测定可能略微偏向于更年轻的年代。另一方面，线粒体DNA（mtDNA）似乎在哺乳动物中以比η-珠蛋白基因更均匀的速率进化。与η-珠蛋白时钟相比，mtDNA时钟中猩猩与黑猩猩的分裂日期之比更大，这表明早期人类和早期非洲猿之间可能存在mtDNA渐渗现象，以及/或猩猩和非洲猿共同祖先种之间可能存在mtDNA多态性，从而掩盖了猩猩真正的种间分离日期。
Divergence dates among primates were estimated by molecular clock analysis of DNA sequence data. A molecular clock of η-globin pseudogene was calibrated by setting the date of divergence between Catarrhini and Platyrrhini at 38 million years (Myr) ago. The clock gave dates of 25.3±2.4, 11.9±1.7, 5.9±1.2, and 4.9±1.2 Myr ago (± refers to standard error) for the separation of rhesus monkey, orangutan, gorilla, and chimpanzee, respectively, from the line leading to humans. In placing confidence intervals of the estimates in a robust way, a bootstrap method was used. The 95% confidence intervals are 20.5–29.5, 9.0–14.8, 4.1–7.8, and 3.1–7.0 Myr ago for the separation of rhesus monkey, orangutan, gorilla, and chimpanzee, respectively. By a molecular clock dating of the Prosimii-Anthropoidea splitting, it was suggested that the evolutionary rate of the η-globin gene was high early in primate evolution and subsequently decreased in the line of Anthropoidea. And, by a relative rate test using bootstrap sampling, the possibility of further decrease of the rate (more than 10%) in the line of Hominoidea compared with that of Cercopithecoidea was suggested. Therefore, the above dating of the splittings within Hominoidea may be biased slightly toward younger dates. On the other hand, mitochondrial DNA (mtDNA) seems to have evolved in mammals with a more uniform rate than the η-globin gene. The ratio of the dates of orangutan splitting to chimpanzee splitting is larger for the mtDNA clock than that for the η-globin clock, suggesting the possibilities of mt-DNA introgression among the early hominids and the early African apes, and/or of mtDNA polymorphism within the common ancestral species of orangutan and the African apes that obscures the date of the true species separation of orangutans.