Konkel D A, Maizel J V, Leder P
Cell. 1979 Nov;18(3):865-73. doi: 10.1016/0092-8674(79)90138-7.
We have determined the entire nucleotide sequence of a cloned mouse beta--globinminor gene and compared it to the closely related sequence of the betamajor gene. These two genes differ by nine amino acids and presumably evolved from a common ancestral gene as recently as 50 million years ago. Since these genes are closely linked and coordinately expressed, they provide an especially favorable opportunity to assess selection and mutation as these processes affect genes under similar constraints. We find that evolution has preserved these two genes in two short segments of DNA which include their immediately adjacent flanking regions. These regions presumably encode functions that are necessary for proper globin gene expression. In contrast, the more distal flanking sequences and major segments of the long intervening sequences have diverged much more sharply. The homology pattern in these genes also provides considerable insight into the mechanisms by which less constrained nucleotide sequences diverge rapidly. Change in such regions apparently occurs less by point mutation than by insertion, deletion and duplication of relatively short segments of the genome.
我们已经确定了一个克隆的小鼠β-珠蛋白小基因的完整核苷酸序列，并将其与β-珠蛋白大基因的密切相关序列进行了比较。这两个基因有九个氨基酸不同，大概是在距今仅5000万年前从一个共同的祖先基因进化而来的。由于这些基因紧密连锁并协调表达，它们提供了一个特别有利的机会来评估选择和突变，因为这些过程会影响处于相似限制条件下的基因。我们发现进化在DNA的两个短片段中保留了这两个基因，这两个片段包括它们紧邻的侧翼区域。这些区域大概编码了珠蛋白基因正常表达所必需的功能。相比之下，更远端的侧翼序列和长间隔序列的主要部分分歧要大得多。这些基因中的同源模式也为较少受限制的核苷酸序列快速分歧的机制提供了相当多的见解。这些区域的变化显然较少通过点突变发生，而更多是通过基因组相对短片段的插入、缺失和重复发生。
