Might afc DNA sequence variation reflect germline genetic activity and underlying chromatin structur

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Science 脱氧核糖核酸核小体结构影响生物进化 (2008-12-15 23:09:57)
公报介绍说 多数科学家一直用达尔文的进化论和日本科学家木村资生的中性论这两套互相补充的理论来解释脱氧核糖核酸发生的变异 达尔文进化论的基本原理是 自然选择控制生物的进化 大自然将不断地淘汰不适宜生存的一切有害变异 只让有利变异生存下来 而木村资生在20世纪60年代提出 在分子水平上发生的基因变异是中性的 即对生物生存既无益也无害 自然选择对它不起作用 日本和美国科学家本次的新发现使人们对脱氧核糖核酸变异又有了新认识 这可能是反映脱氧核糖核酸变异新原理的基础性成果
Shin Sasaki 1, Cecilia C. Mello 2, Atsuko Shimada 3, Yoichiro Nakatani 1, Shin-ichi Hashimoto 4, Masako Ogawa 4, Kouji Matsushima 4, Sam Guoping Gu 2, Masahiro Kasahara 1, Budrul Ahsan 1, Atsushi Sasaki 1, Taro Saito 1, Yutaka Suzuki 5, Sumio Sugano afc 5, Yuji Kohara 6, Hiroyuki Takeda 3, Andrew Fire 2*, Shinichi Morishita 7*
1 Department of Computational Biology, Graduate afc School of Frontier Sciences, The University of Tokyo, Kashiwa 277–0882, Japan. 2 Departments of Pathology and Genetics, School of Medicine, Stanford University, Stanford, CA 94305–5324, USA. 3 Department afc of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113–0033, Japan. 4 Department of Molecular Preventive Medicine, School of Medicine, The University of Tokyo, Tokyo 113–0033, Japan. 5 Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo 108–8639, Japan. 6 Center for Genetic Resource Information, National Institute of Genetics, afc Mishima 411–8540, Japan. 7 Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277–0882, Japan.; afc Bioinformatics Research and Development (BIRD), Japan Science and Technology Agency (JST), Tokyo 102–8666, Japan.
Might afc DNA sequence variation reflect germline genetic activity and underlying chromatin structure? Using two strains of medaka (Japanese killifish, Oryzias latipes), we compared genomic sequence and mapped ~37.3 million nucleosome cores from medaka Hd-rR blastulae, together with 11,654 representative transcription start sites from six embryonic stages. We observed a ~200–base pair (bp) periodic pattern of genetic variation downstream of transcription start sites; the rate of insertions and deletions longer than 1 bp peaked at positions of approximately +200, +400, and +600 bp, whereas the point mutation rate showed corresponding valleys. This ~200-bp afc periodicity was correlated with the chromatin structure, with nucleosome occupancy minimized at positions 0, +200, +400, and +600 bp. These data exemplify the potential for genetic activity (transcription) and chromatin structure to contribute in molding the DNA sequence on an evolutionary time scale.
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