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原帖由 柏桐 於 2007-9-18 21:49 發表
特別是人與黑猩猩在transposon上的差別. 還是有疑問.
人與黑猩猩在transposon上的差別反映了二者在約700~600萬年前分離以後各自的進化路徑和程度。我看過一篇去年的比較新的研究,比較了二者在transposons上的差別。二者不同的transposon insertion共有10719個,其中人類有7786個,黑猩猩有2933個。這說明總體上來講,人類在與黑猩猩分開以後,進化得更intensive些。也部分能說明為什麼人和黑猩猩基因>98%相同的情況下,仍然有這麼大的差別,因為分開后,進化依然非常活躍。蠻有意思的論文,你可以找來讀讀。其中的技術細節如果你不熟悉,可以不管它,整體實際上很容易讀懂的。如果你找不到,我可以給你全文,以下是long citation.
Ryan E. Mills, E. Andrew Bennett, Rebecca C. Iskow, Christopher T. Luttig, Circe Tsui, W. Stephen Pittard, and Scott E. Devine
Recently Mobilized Transposons in the Human and Chimpanzee Genomes
The American Journal of Human Genetics, volume 78 (2006), pages 671–679
Abstract: Transposable genetic elements are abundant in the genomes of most organisms, including humans. These endogenous mutagens can alter genes, promote genomic rearrangements, and may help to drive the speciation of organisms. In this study, we identified almost 11,000 transposon copies that are differentially present in the human and chimpanzee genomes. Most of these transposon copies were mobilized after the existence of a common ancestor of humans and chimpanzees, 6 million years ago. Alu, L1, and SVA insertions accounted for >95% of the insertions in both species. Our data indicate that humans have supported higher levels of transposition than have chimpanzees during the past several million years and have amplified different transposon subfamilies. In both species, 34% of the insertions were located within known genes. These insertions represent a form of species-specific genetic variation that may have contributed to the differential evolution of humans and chimpanzees. In addition to providing an initial overview of recently mobilized elements, our collections will be useful for assessing the impact of these insertions on their hosts and for studying the transposition mechanisms of these elements. |
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