Koonin Eugene V
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
J Hered. 2009 Sep-Oct;100(5):618-23. doi: 10.1093/jhered/esp056. Epub 2009 Jul 17.
Evolutionary reconstructions using maximum likelihood methods point to unexpectedly high densities of introns in protein-coding genes of ancestral eukaryotic forms including the last common ancestor of all extant eukaryotes. Combined with the evidence of the origin of spliceosomal introns from invading Group II self-splicing introns, these results suggest that early ancestral eukaryotic genomes consisted of up to 80% sequences derived from Group II introns, a much greater contribution of introns than that seen in any extant genome. An organism with such an unusual genome architecture could survive only under conditions of a severe population bottleneck.
使用最大似然法进行的进化重建表明，在包括所有现存真核生物的最后共同祖先在内的祖先真核生物形式的蛋白质编码基因中，内含子的密度出乎意料地高。结合剪接体内含子起源于入侵的II类自我剪接内含子的证据，这些结果表明，早期祖先真核生物基因组中高达80%的序列来自II类内含子，内含子的贡献比任何现存基因组都要大得多。具有这种不寻常基因组结构的生物体只有在严重种群瓶颈的条件下才能存活。
