Patterns and rates of indel evolution in processed pseudogenes from humans and murids
Patterns and rates of indel evolution in processed pseudogenes from humans and murids
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DOI：
10.1016/s0378-1119(97)00398-3
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发表时间：
1997-12-31
期刊：
影响因子：
3.5
通讯作者：
Graur, D
中科院分区：
文献类型：
--
作者：
Ophir, R;Graur, D
indel（删除和插入）进化的模式和速率在来自人类和鼠类（小鼠和大鼠）的 156 个独立衍生的加工假基因中进行了表征。明确鉴定出总共 441 个缺失和 161 个插入。在 109 个假基因的子集中，我们验证并确认了插入缺失几乎完全发生在假基因中的假设，因此，在假基因与其功能旁系同源物之间的比较中，可以为插入缺失事件分配极性。通过比较末端截断和内部缺失的特征，我们发现截断是通过与内部缺失不同的途径产生的假设的支持。发现每个假基因的删除和插入数量随着时间单调增加。删除平均每 40 个核苷酸取代发生一次，而插入则少得多，每 100 个取代发生一次，这表明涉及缺失形成的机制很可能与负责形成插入的机制不同。然而，假基因的年龄仅分别解释了每个位点缺失和插入数量变化的 20% 和 13%，这表明进化时间以外的因素可能在 indel 积累的进化动态中发挥重要作用。由于先前已证明鼠科动物的取代率高于人类，因此我们推断鼠科动物的删除和插入累积比例比人类更快。鼠类和人类基因组中的删除和插入对基因组大小没有显着影响。 (C) 1997 Elsevier Science B.V.
Patterns and rates of indel (deletions and insertions) evolution were characterized in 156 independently derived processed pseudogenes from humans and murids (mice and rats). A total of 441 deletions and 161 insertions were unambiguously identified. On a subset of 109 pseudogenes, we verified and confirmed the assumption that indels occur almost exclusively in the pseudogene and, therefore, in comparisons between pseudogenes and their functional paralogs, it is possible to assign polarity to the indel event. By comparing the characteristics of terminal truncations with those of internal deletions, we find support for the hypothesis that truncations are generated through a different pathway than internal deletions. The number of deletions and insertions per pseudogene was found to increase monotonically with time. Deletions occur on average once every 40 nucleotide substitutions, whereas insertions are much rarer, occurring once every 100 substitutions, indicating that the mechanisms involved in deletion formation are most probably different from those responsible for the formation of insertions. The age of the pseudogene, however, explained only 20 and 13%, respectively, of the variation in the number of deletions and insertions per site, indicating that factors other than evolutionary time may play a significant role in the evolutionary dynamics of indel accumulation. Since the rate of substitution has been previously shown to be higher in murids than in humans, we deduce that deletions and insertions accumulate proportionally faster in murids than in humans. Deletions and insertions in murid and human genomes do not contribute significantly to genome size. (C) 1997 Elsevier Science B.V.