Bailey W J, Hayasaka K, Skinner C G, Kehoe S, Sieu L C, Slightom J L, Goodman M
Department of Molecular Biology and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201.
Mol Phylogenet Evol. 1992 Jun;1(2):97-135. doi: 10.1016/1055-7903(92)90024-b.
Additional DNA sequence information from a range of primates, including 13.7 kb from pygmy chimpanzee (Pan paniscus), was added to data sets of beta-globin gene cluster sequence alignments that span the gamma 1, gamma 2, and psi eta loci and their flanking and intergenic regions. This enlarged body of data was used to address the issue of whether the ancestral separations of gorilla, chimpanzee, and human lineages resulted from only one trichotomous branching or from two dichotomous branching events. The degree of divergence, corrected for superimposed substitutions, seen in the beta-globin gene cluster between human alleles is about a third to a half that observed between two species of chimpanzee and about a fourth that between human and chimpanzee. The divergence either between chimpanzee and gorilla or between human and gorilla is slightly greater than that between human and chimpanzee, suggesting that the ancestral separations resulted from two closely spaced dichotomous branchings. Maximum parsimony analysis further strengthened the evidence that humans and chimpanzees share the longest common ancestry. Support for this human-chimpanzee clade is statistically significant at P = 0.002 over a human-gorilla clade or a chimpanzee-gorilla clade. An analysis of expected and observed homoplasy revealed that the number of sequence changes uniquely shared by human and chimpanzee lineages is too large to be attributed to homoplasy. Molecular clock calculations that accommodated lineage variations in rates of molecular evolution yielded hominoid branching times that ranged from 17-19 million years ago (MYA) for the separation of gibbon from the other hominoids to 5-7 MYA for the separation of chimpanzees from humans. Based on the relatively late dates and mounting corroborative evidence from unlinked nuclear genes and mitochondrial DNA for the close sister grouping of humans and chimpanzees, a cladistic classification would place all apes and humans in the same family. Within this family, gibbons would be placed in one subfamily and all other extant hominoids in another subfamily. The later subfamily would be divided into a tribe for orangutans and another tribe for gorillas, chimpanzees, and humans. Finally, gorillas would be placed in one subtribe with chimpanzees and humans in another, although this last division is not as strongly supported as the other divisions.
一系列灵长类动物的额外DNA序列信息，包括来自倭黑猩猩（Pan paniscus）的13.7 kb，被添加到跨越γ1、γ2和ψη基因座及其侧翼和基因间区域的β-珠蛋白基因簇序列比对数据集中。这一扩大的数据体被用于解决大猩猩、黑猩猩和人类谱系的祖先分离是仅由一次三分分支还是由两次二分分支事件导致的问题。在人类等位基因之间的β-珠蛋白基因簇中观察到的，经叠加替换校正后的分歧程度，约为两种黑猩猩之间观察到的分歧程度的三分之一到一半，约为人类与黑猩猩之间分歧程度的四分之一。黑猩猩与大猩猩之间或人类与大猩猩之间的分歧略大于人类与黑猩猩之间的分歧，这表明祖先分离是由两次紧密间隔的二分分支导致的。最大简约分析进一步强化了人类和黑猩猩拥有最长共同祖先的证据。在P = 0.002时，相对于人类-大猩猩分支或黑猩猩-大猩猩分支，对人类-黑猩猩分支的支持在统计学上具有显著性。对预期和观察到的同塑性的分析表明，人类和黑猩猩谱系独特共享的序列变化数量太大，不能归因于同塑性。考虑到分子进化速率的谱系变化的分子钟计算得出，类人猿的分支时间范围从长臂猿与其他类人猿分离的1700 - 1900万年前（MYA）到黑猩猩与人类分离的500 - 700万年前。基于相对较晚的日期以及来自不连锁核基因和线粒体DNA的越来越多的确凿证据支持人类和黑猩猩为近亲姐妹群，一种分支分类法将所有猿类和人类归为同一科。在这个科内，长臂猿将被置于一个亚科，所有其他现存类人猿置于另一个亚科。后一个亚科将分为一个猩猩部落和另一个大猩猩、黑猩猩和人类部落。最后，大猩猩将被置于一个亚部落，黑猩猩和人类置于另一个亚部落，尽管最后这个划分不像其他划分那样得到强有力的支持。
