Forsdyke D R
Department of Biochemistry, Queen's University, Kingston, Ontario, Canada.
J Mol Evol. 1995 Nov;41(5):582-6. doi: 10.1007/BF00175816.
A correspondence between open reading frames in sense and antisense strands is expected from the hypothesis that the prototypic triplet code was of general form RNY, where R is a purine base, N is any base, and Y is a pyrimidine. A deficit of stop codons in the antisense strand (and thus long open reading frames) is predicted for organisms with high G + C percentages; however, two bacteria (Azotobacter vinelandii, Rhodobacter capsulatum) have larger average antisense strand open reading frames than predicted from (G + C)%. The similar codon frequencies found in sense and antisense strands can be attributed to the wide distribution of inverted repeats (stem-loop potential) in natural DNA sequences.
从三联体密码原型为一般形式RNY(其中R为嘌呤碱基,N为任意碱基,Y为嘧啶碱基)这一假设可以预期,有义链和反义链中的开放阅读框之间存在对应关系。对于高G + C百分比的生物体,预计反义链中的终止密码子会不足(从而有长的开放阅读框);然而,两种细菌(棕色固氮菌、荚膜红细菌)的反义链平均开放阅读框比根据(G + C)%预测的要大。有义链和反义链中发现的相似密码子频率可归因于天然DNA序列中反向重复序列(茎环结构潜力)的广泛分布。