de Jong W W, Rydén L
Nature. 1981 Mar 12;290(5802):157-9. doi: 10.1038/290157a0.
Deletions and insertions of base pairs in dNA, jointly called gap events, are one of the major sources of evolutionary change at the molecular level. On the basis of very limited data, Fitch has suggested that deletions might be expressed more often than insertions in proteins. We have examined the presently available homologous protein sequences, and observed that in the course of evolution, deletions of amino acids have indeed occurred about four times more frequently than insertions. An even higher preponderance of deletions over insertions (ten times or more) is found in recent spontaneous and induced mutants of genes or proteins. We propose here a mutational mechanism to explain this predominance of deletions.
DNA中碱基对的缺失和插入，统称为缺口事件，是分子水平进化变化的主要来源之一。基于非常有限的数据，菲奇提出，在蛋白质中，缺失可能比插入更常表现出来。我们研究了目前可用的同源蛋白质序列，观察到在进化过程中，氨基酸的缺失确实比插入发生的频率高出约四倍。在最近基因或蛋白质的自发和诱导突变体中，发现缺失比插入的优势甚至更高（十倍或更多）。我们在此提出一种突变机制来解释这种缺失的优势。
