Milkman R, Crawford I P
Science. 1983 Jul 22;221(4608):378-80. doi: 10.1126/science.6346486.
Nucleotide sequences of translated regions of the trp operon in 12 wild strains of Escherichia coli reveal striking uniformity among eight strains (suggesting recent common ancestry and supporting the importance of periodic selection in natural populations) and clustered substitutions in four strains (implicating events affecting runs of nucleotides).
对12株野生大肠杆菌色氨酸操纵子翻译区域的核苷酸序列分析显示,其中8株具有显著的一致性(表明它们有较近的共同祖先,并支持周期性选择在自然种群中的重要性),另外4株存在成簇的替换(意味着发生了影响核苷酸序列片段的事件)。