GENE DUPLICATIONS AS A RECURRENT THEME IN THE EVOLUTION OF THE HUMAN PSEUDOAUTOSOMAL REGION-1 - ISOLATION OF THE GENE ASMTL

We have isolated a novel gene, ASMTL (acetylserotonin methyltransferas e-like), in the pseudoautosomal region (PAR1) on the human sex chromos omes. ASMTL represents a unique fusion product of two different full-l ength genes of different evolutionary origin and function. One part is homologous to the bacterial maf/orfE genes. The other part shows sign ificant homology to the entire open reading frame of the previously de scribed pseudoautosomal gene ASMT, encoding the enzyme catalysing the last step in the synthesis of melatonin. We have also detected the ide ntity of one exon (1A) of ASMT to exon 3 in yet another pseudoautosoma l gene, XE7. The data presented suggest that exon duplication and exon shuffling as well as gene fusion may represent common characteristics in the pseudoautosomal region.