Erickson L M, Maeda N
Department of Pathology, University of North Carolina at Chapel Hill 27599-7525.
Genomics. 1994 Aug;22(3):579-89. doi: 10.1006/geno.1994.1431.
Parallel occurrences of evolutionary events in the haptoglobin gene clusters of rhesus monkeys and humans were studied. We found six different haplotypes among 11 individuals from two rhesus monkey families. The six haplotypes include two types of haptoglobin gene clusters: one type with a single gene and the other with two genes. DNA sequence analysis indicates that the one-gene and the two-gene clusters were both formed by unequal homologous crossovers between two genes of an ancestral three-gene cluster, near exon 5, the longest exon of the gene. This exon is also the location where a separate unequal homologous crossover occurred in the human lineage, forming the human two-gene haptoglobin gene cluster from an ancestral three-gene cluster. The occurrence of independent homologous unequal crossovers in rhesus monkey and in human within the same region of DNA suggests that the evolutionary history of the haptoglobin gene cluster in primates is the consequence of frequent homologous pairings facilitated by the longest and most conserved exon of the gene.
对恒河猴和人类触珠蛋白基因簇中进化事件的平行发生情况进行了研究。我们在来自两个恒河猴家族的11个个体中发现了六种不同的单倍型。这六种单倍型包括两种类型的触珠蛋白基因簇：一种是单基因类型，另一种是双基因类型。DNA序列分析表明，单基因簇和双基因簇均由祖先三基因簇的两个基因在靠近外显子5（该基因最长的外显子）处发生不等位同源交叉形成。这个外显子也是人类谱系中发生单独不等位同源交叉的位置，由祖先三基因簇形成了人类双基因触珠蛋白基因簇。恒河猴和人类在DNA的同一区域发生独立的同源不等位交叉，这表明灵长类动物触珠蛋白基因簇的进化史是该基因最长且最保守的外显子促进频繁同源配对的结果。
