New World, but not Old World, monkeys carry several genes encoding β‐microseminoprotein

It was shown by Southern hybridization that cotton‐top tamarin and common marmoset, New World monkeys, carry three or more genes encoding β‐microseminoprotein, also known as PSP 94 . In contrast, the genomes of Old World monkeys, as represented by rhesus macaque and sacred baboon, contain a single gene. Clones containing three different genes encoding β‐microseminoprotein were isolated from a cotton‐top tamarin genomic library. They carry two complete genes of four exons and a third gene lacking the first exon. The structure suggests that the three genes are functionally active and give rise to transcripts that are ≈ 86% similar in sequence. By sequencing one gene in full, it was shown that the introns carry an excess of interspersed repeats, on average 29% of the introns consist of Alu repeats. A phylogenetic analysis demonstrated that the genes probably arose in New World monkeys after the separation from Old World primates.