黑猩猩归入人属科学界引起争论

美国韦恩州立大学科学家Morris Goodman及同事最近通过研究，建议将黑猩猩归入人属，因为黑猩猩编码功能基因的遗传信息与人的同源性可达99.4%。这一研究成果发表在19日的美国《全国科学院学报》。传统上，黑猩猩是与大猩猩、猩猩等一起归进猩猩科。由于这一建议涉及到人类进化的一些核心观念，因此立即在科学界引起争论。美国韦恩州立大学科学家古德曼及同事最近建议将黑猩猩归入人属，因为黑猩猩编码功能基因的遗传信息与人极其相似。由于这一建议涉及到人类进化的一些核心观念，因此立即在科学界引起争论。　　古德曼等人选取人、黑猩猩、大猩猩、猩猩、旧大陆猴和鼠为研究对象，比较了这6个物种在97个功能基因上的差异程度。分析结果发现，在编码功能基因的DNA序列方面，黑猩猩与人的相同之处可达99.4%，最为接近。新一期美国《全国科学院学报》刊登了他们的研究报告。　　生物的分类单位由大到小依次为界、门、纲、目、科、属和种。从分类学上说，现代人类属于动物界、脊索动物门、哺乳纲、灵长目、人科、人属、智人种。传统上，黑猩猩不被列入人类所处的人科，而是与大猩猩、猩猩等一起归进猩猩科。古德曼等人基于研究结果建议，所有现存的类人猿都可以被列入人科，其中黑猩猩应该被进一步划入人科下的人属。　　古德曼称，根据DNA分析结果来调整现有的分类，将黑猩猩和人类归为同属，其意义在于能够保证用客观的而非以人类为中心的主观标准来研究生物进化。但一些专家指出，即使利用DNA分析，不同思路得出的黑猩猩与人类之间的差异也不相同，如美国加利福尼亚理工学院科学家布里滕的研究显示，黑猩猩与人类遗传信息上的差异可能达到5%，高于科学家普遍认为的1.5%，因此古德曼等的建议要想被科学界接受尚有一定难度。 DNA Demands Chimps Be Grouped in the Human Genus, Say Wayne State Researchers Proposed changes in the primate order are stirring up evolutionary debate. Humans and chimpanzees should be grouped in the same genus, Homo, according to WSU researchers in a May 19 article (#2172) published in the Proceedings of the National Academy of Sciences. Although WSU Morris Goodman, PhD, has already proven with non-coding DNA sequences that chimpanzees are closest in kinship to humans rather than to gorillas, evolutionary traditionalists say chimps and humans are functionally markedly different and therefore belong on different branches of the family tree. New analyses show humans and chimpanzees to be 99.4 percent identical in the functionally-important DNA, which codes for proteins and is shaped by natural selection. This provides further evidence for revisions in our genus classification. Dr. Goodman proposes that all living apes should occupy the family Hominidae (which currently contains only humans), and that both humans and chimpanzees should occupy the genus Homo. In traditional taxonomic schemes that are still widely employed, humans are classified as Hominids, while orangutans, gorillas, and chimpanzees are classified as Pongids. Genetically, however, chimpanzees are more closely related to humans than they are to gorillas. The accumulating DNA evidence provides an objective non-anthropocentric view of the place of humans in evolution. We humans appear as only slightly remodeled chimpanzee-like apes,?Dr. Goodman said. The WSU research team compared 97 functional genes in six different species: humans, chimpanzees, gorillas, orangutans, old world monkeys, and mice. Based on genetic mutation tracking rates, the scientists constructed an evolutionary tree that measured the degree of relatedness among the six species. Chimpanzees and humans were the most closely related, sharing 99.4 percent identity at nonsynonymous (functionally important) sites and 98.4 percent at synonymous sites (functionally much less important). Researchers determined that humans and chimpanzees diverged from a common ancestor roughly five to six million years ago, which in turn diverged from gorillas about six to seven million years ago. Revisions to our classification system would have far-reaching implications, much more important, in fact, than proving that humans and chimps are barely divergent. Such revisions would ensure that objective, scientific measures of similarity and dissimilarity are used, rather than anthropocentric, subjective observations. Sound genetic analysis should always be the basis for understanding the place of humans in evolution,?Dr. Goodman asserts. These taxonomic changes had been proposed previously by several evolutionary experts, including Dr. Goodman, but a difference of scientific philosophies is at play. Traditional anthropologists argue that chimps are functionally different than humans because, for example, they lack spoken language and their genetic disease susceptibilities are different. In contrast, Dr. Goodman opens his article with a quote from Charles Darwin that says: as we have no record of the lines of descent, the lines can be discovered only by observing the degrees of resemblance between the beings which are to be classed. For this object numerous points of resemblance are of much more importance than the amount of similarity or dissimilarity in a few points. Dr. Goodman is a distinguished professor in the Wayne State University School of Medicine抯 Department of Anatomy and Cell Biology and the Center for Molecular Medicine and Genetics. In 1962, he sparked great debate when he originally asserted that chimpanzees and gorillas are genetically more closely related to humans than to other apes. His research has since been widely accepted and his work in this area has not only impacted the study of humankind抯 place in nature, but also has important implications for medical science. The full article, natural Selection Role in Shaping 99.4% Nonsynonymous DNA Identity Between Congeneric Humans and Chimpanzees,?is featured as article #03-2172 in the May 19-May 23, 2003 issue of the Proceedings of the National Academy of Sciences. It can be viewed online, beginning May 19, at: http://www.pnas.org Co-authors on Dr. Goodman inaugural PNAS article, since his 2002 election into the National Academy of Sciences, are: Derek Wildman, Monica Uddin, Guozhen Liu, and Lawrence Grossman. (责任编辑：泉水)

搜索

热门标签: