Stoltzfus A, Logsdon J M, Palmer J D, Doolittle W F
Canadian Institute for Advanced Research Program in Evolutionary Biology, and Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4H7.
Proc Natl Acad Sci U S A. 1997 Sep 30;94(20):10739-44. doi: 10.1073/pnas.94.20.10739.
Alignments of homologous genes typically reveal a great diversity of intron locations, far more than could fit comfortably in a single gene. Thus, a minority of these intron positions could be inherited from a single ancestral gene, but the larger share must be attributed to subsequent events of intron gain or intron "sliding" (movement from one position to another within a gene). Intron sliding has been argued from cases of discordant introns and from putative spatial clustering of intron positions. A list of 32 cases of discordant introns is presented here. Most of these cases are found to be artefactual. The spatial and phylogenetic distributions of intron positions from five published compilations of gene data, comprising 205 intron positions, have been examined systematically for evidence of intron sliding. The results suggest that sliding, if it occurs at all, has contributed little to the diversity of intron positions.
同源基因的比对通常显示出内含子位置的巨大多样性，远远超过单个基因所能容纳的范围。因此，这些内含子位置中少数可能继承自单个祖先基因，但更大比例的内含子位置必须归因于随后的内含子获得事件或内含子“滑动”（在基因内从一个位置移动到另一个位置）。从不一致内含子的情况以及内含子位置的假定空间聚类中可以看出内含子滑动现象。这里列出了32个不一致内含子的案例。发现这些案例中的大多数都是人为造成的。系统地检查了来自五份已发表的基因数据汇编（包含205个内含子位置）的内含子位置的空间和系统发育分布，以寻找内含子滑动的证据。结果表明，即使存在滑动现象，它对内含子位置多样性的贡献也很小。
