Abstract
Retroposons become remarkable DNA markers in the study of the evolution of DNA in the recent decade. Retroposons are formed by reverse transcriptase from the RNA and inserted in the random position of the genomic DNA. If it has the promoter region of RNA polymerase, the retroposon will be expressed again and increase copy numbers. The active retroposons such as phosphoglycerate kinase (McCarry and Thomas 1984), BC200, one of the Alu element (Cheng et al. 1997), amylase gene (Samuelson et al. 1990) and others were summarized.
A novel processed gene was found in the intergenic α-globin gene region in macaques, which had an open reading frame of 117 amino acids, poly (A) signal, poly (A) and a flanking direct repeat. It was named P117 gene. The frequency of insertion of this retrosequence P117 (P117R) was different from locality in the long-tailed macaques, while, the P117R could not be found in 49 Japanese macaques from three places in the central part of Japan. Also, hominoid genome, so far as examined, do not have this retroposon. The parental P117 (P117P) gene in the macaque has the length by 3kb, which was longer than that in human by 1kb. The P117P was consisted from four exons and three introns.
The sequence of P117R from the long-tailed and Formosan macaques, and capchin were determined. The comparison of the synonymous (kS) and the non-synonymous substitution number (kA) between P117P and P117R, and the frequency of insertion in macaques, suggest that the insertion occurred after the divergence of the macaques from the hominoid lineage but just before the divergence of the macaque species.
In the case of capchin, the P117R was assumed to be inserted at around the divergence time between the New World and the Old World monkeys.
