Liu Ge, Zhao Shaying, Bailey Jeffrey A, Sahinalp S Cenk, Alkan Can, Tuzun Eray, Green Eric D, Eichler Evan E
Department of Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA.
Genome Res. 2003 Mar;13(3):358-68. doi: 10.1101/gr.923303.
We performed a detailed analysis of both single-nucleotide and large insertion/deletion events based on large-scale comparison of 10.6 Mb of genomic sequence from lemur, baboon, and chimpanzee to human. Using a human genomic reference, optimal global alignments were constructed from large (>50-kb) genomic sequence clones. These alignments were examined for the pattern, frequency, and nature of mutational events. Whereas rates of single-nucleotide substitution remain relatively constant (1-2 x 10(-9) substitutions/site/year), rates of retrotransposition vary radically among different primate lineages. These differences have lead to a 15%-20% expansion of human genome size over the last 50 million years of primate evolution, 90% of it due to new retroposon insertions. Orthologous comparisons with the chimpanzee suggest that the human genome continues to significantly expand due to shifts in retrotransposition activity. Assuming that the primate genome sequence we have sampled is representative, we estimate that human euchromatin has expanded 30 Mb and 550 Mb compared to the primate genomes of chimpanzee and lemur, respectively.
我们基于狐猴、狒狒、黑猩猩与人类10.6 Mb基因组序列的大规模比较，对单核苷酸和大的插入/缺失事件进行了详细分析。使用人类基因组参考序列，从大型（>50 kb）基因组序列克隆构建了最佳全局比对。检查这些比对中的突变事件模式、频率和性质。单核苷酸替换率相对恒定（1 - 2×10⁻⁹替换/位点/年），而逆转座率在不同灵长类谱系中差异很大。这些差异导致在过去5000万年的灵长类进化过程中人类基因组大小扩大了15% - 20%，其中90%是由于新的逆转座子插入。与黑猩猩的直系同源比较表明，由于逆转座活性的变化，人类基因组仍在显著扩展。假设我们所采样的灵长类基因组序列具有代表性，我们估计与黑猩猩和狐猴的灵长类基因组相比，人类常染色质分别扩展了30 Mb和550 Mb。
