Zimmer E A, Martin S L, Beverley S M, Kan Y W, Wilson A C
Proc Natl Acad Sci U S A. 1980 Apr;77(4):2158-62. doi: 10.1073/pnas.77.4.2158.
Rapid cycles of gene duplication and loss appear to have been going on in the region coding for the alpha chain of adult hemoglobin. This is inferred from restriction endonuclease analysis of the alpha gene region in five species of apes, whose common ancestor lived about 10 million years ago. Because all five species resemble humans in having duplicate alpha genes, the duplicate state of this region is probably at least as old as the common ancestor of all these species. However, the alpha polypeptides within these species are about 10 times more alike than is expected for 10 million years of divergent evolution. Thus, the alpha polypeptides within each species have been evolving in concert. Changes in gene number have also taken place in the apes. Whereas the predominant number of alpha genes per chromosome is two for most species, it is three for chimpanzees. Concerted evolution appears also to have occurred, but far more slowly, in the region coding for the adult beta-like chains of hemoglobin. Consideration of the structural differences between the two regions leads to the hypothesis that the lengths of the noncoding regions are important determinants of the rates at which genes are gained and lost by intergenic recombination.
在成人血红蛋白α链的编码区域，基因复制和丢失的快速循环似乎一直在进行。这是通过对五种猿类的α基因区域进行限制性内切酶分析推断出来的，这些猿类的共同祖先生活在大约1000万年前。由于所有这五个物种都像人类一样拥有重复的α基因，所以这个区域的重复状态可能至少与所有这些物种的共同祖先一样古老。然而，这些物种中的α多肽彼此之间的相似程度比预计的1000万年的趋异进化要高出约10倍。因此，每个物种内的α多肽一直在协同进化。猿类中也发生了基因数量的变化。虽然大多数物种每条染色体上α基因的主要数量是两个，但黑猩猩是三个。在成人血红蛋白β样链的编码区域似乎也发生了协同进化，但速度要慢得多。对这两个区域结构差异的考虑导致了这样一个假设，即非编码区域的长度是通过基因间重组获得和丢失基因速率的重要决定因素。
