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Genetic Diversity of Primates and The Future of Man

灵长类动物的遗传多样性和人类的未来

基本信息

批准号：
08404052
负责人：
TAKAHATA Naoyuki
金额：
$ 17.98万
依托单位：
The Graduate University for Advanced Studies
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1999
项目状态：
已结题

项目摘要

(1) In, collaboration with Dr. Jan Klein in Max-Plank-Institut fur Biologie (Tubingen), the principal investigator (N. T.) has been co-authoring a popular science book for these four years. The book is entitled "Where do we come from? The molecular evidence for human descent" and is composed of 10 chapters. This year, the PI visited the MPI for three weeks to discuss the whole contents and write Chapter 6-10. The book covers several fields of biology, such as molecular biology, population genetics, anthropology, evolutionary genetics, and primatology. Many results obtained through this research project will be reproduced in the book. By the end of this calendar year, the book is planned to be distributed worldwide.(2) In general, neutral genes in the human population exhibit relatively shallow genealogies. The time scale of such genealogies is of the order of N generations, where N is the effective population size and estimated as 10,000 during the Pleistocene. A notable exception is t … More hose genes, which are linked to the Major Histocompatibility Complex (Mhc) loci. The genealogy at these linked neutral loci is much deeper than that of unlinked neutral genes. This, deep genealogy and high extent of nucleotide diversity result from linkage effects of balancing selection at Mhc loci. The nucleotide diversity of linked genes decreases, as the recombination rate between an Mhc locus and a linked neutral locus increases. Conversely, under an appropriate population genetics model, it is possible to estimate the recombination rate from the observed extent of the nucleotide diversity at a linked neutral locus. We have applied this principle to the human Mhc (HLA) region. The result shows that the recombination rate is generally 1 cM per 1 Mb, but it fluctuates considerably from locus to locus. In particular, the genomic region telomeric to the HLA-A locus is subjected to extremely infrequent recombination.(3) We have expanded our previous analysis about the demographic history of human lineages during the entire period of primate evolution. We have constructed aDNA sequence database comprising of 45 sets of orthologous nucleotide sequences among the human, the chimpanzee, and the gorilla. It is confirmed that the chimpanzee is the closest relative to the human. However, individual sets of genes can support this conclusion only weakly. This weak support mainly stems from the presence of phylogenetically incompatible sites in an individual set of DNA sequences. The major cause of such sequence incompatibility is not due to homoplasy, but due to intragenic recombination among ancestral sequences. The trichotomy problem among the human, the chimpanzee, and the gorilla, or more generally among relatively closely related species can properly be addressed only within this framework. Less

(1)在与Max-Plank-Institut fur Biologie（Tubingen）的Jan Klein博士合作中，首席研究员（N。T.）这四年来一直在合著一本科普书籍。这本书的题目是《我们从哪里来？《人类起源的分子证据》由10章组成。今年，PI访问MPI三周，讨论整个内容并编写第6-10章。这本书涵盖了生物学的几个领域，如分子生物学，群体遗传学，人类学，进化遗传学和灵长类动物学。通过这个研究项目获得的许多成果将在书中重现。到今年年底，这本书计划在全世界发行。(2)一般来说，人类群体中的中性基因表现出相对较浅的谱系。这种谱系的时间尺度是N代，其中N是有效的人口规模，估计在更新世期间为10，000。一个值得注意的例外是t ...更多信息 hose基因，其与主要组织相容性复合体（Mhc）基因座连锁。这些连锁的中性基因座的系谱比非连锁的中性基因的系谱深得多。这一点，深系谱和高程度的核苷酸多样性的结果从连锁效应的平衡选择在Mhc基因座。随着Mhc基因座和连锁中性基因座之间重组率的增加，连锁基因的核苷酸多样性降低。相反，在一个适当的群体遗传学模型下，有可能从观察到的连锁中性基因座上核苷酸多样性的程度来估计重组率。我们已经将这一原则应用于人类MHC（HLA）区域。结果表明，重组率一般为1cM/1 Mb，但在不同位点间有较大的波动。特别地，端粒至HLA-A基因座的基因组区域经历极其罕见的重组。(3)我们已经扩展了我们以前对整个灵长类进化时期人类谱系的人口统计学历史的分析。我们构建了一个包含45组人类、黑猩猩和大猩猩的DNA序列数据库。据证实，黑猩猩是人类最近的亲属。然而，单个基因组只能微弱地支持这一结论。这种微弱的支持主要源于单个DNA序列集中系统发育不相容位点的存在。这种序列不相容性的主要原因不是由于同源性，而是由于祖先序列之间的基因内重组。人类、黑猩猩和大猩猩之间，或者更一般地说，相对密切相关的物种之间的染色体分离问题，只有在这个框架内才能得到适当的解决。少