A novel gene family encoding proteins with highly differing structure because of a rapidly evolving exon
Despite vast differences in primary structure, it is here shown that several predominant semen proteins are encoded by genes that belongs to a common family. Members have their transcription unit split into three exons: the first encoding the signal peptide, the second the secreted protein, while the third exon solely consists of 3' non-translated nucleotides. The first and the third exon are cons