Yagil G
Department of Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
J Mol Evol. 1993 Aug;37(2):123-30. doi: 10.1007/BF02407347.
The frequency of two-base tracts is surveyed in a wide range of eukaryotic genomes using the special program TRACTS. All three two-base families are surveyed: R.Y (A,G.C,T), K.M (A,C.G,T), and S;W (A.T and G.C). Data for the human beta-globin complex, for the tobacco chloroplast, and for 247 nt mammalian promoter regions are presented. All two-base tracts longer than three or four bases are overrepresented to an extent surpassing by far their occurrence in a randomized DNA population in the majority of the genomic regions analyzed; 20-30 long tracts are quite frequent, against the statistical odds. R.Y tracts are found at the largest excess, K.M tract to a slightly lesser extent, while S.W tracts are found at a moderate yet significant excess. The majority of the tracts manifest only a limited extent of tandem repeat structures. The idea that the two base tracts serve as unwinding elements is considered.
使用特殊程序TRACTS对广泛的真核生物基因组中的双碱基序列进行了调查。对所有三个双碱基家族进行了调查：R.Y（A、G、C、T）、K.M（A、C、G、T）和S.W（A.T和G.C）。给出了人类β-珠蛋白复合体、烟草叶绿体和247 nt哺乳动物启动子区域的数据。在大多数分析的基因组区域中，所有长度超过三或四个碱基的双碱基序列的丰度都远远超过它们在随机DNA群体中的出现频率；20 - 30个长序列相当常见，这与统计概率不符。R.Y序列的过量最为明显，K.M序列的过量程度稍小，而S.W序列的过量程度适中但仍很显著。大多数序列仅表现出有限程度的串联重复结构。文中考虑了双碱基序列作为解旋元件的观点。
