The gene encoding guanidinoacetate methyltransferase (GAMT) maps to mouse chromosome 10 near the locus of hesitant mutation affecting male fertility

guanidinoacetate methyltransferase (GAMT) catalyzes the last step of creatine biosynthesis in mammals. Creatine plays an important role in cellular energy metabolism in variety of tissues including brain and male reproductive tract. Congenital deficiency of the enzyme leads to a neurologic disorder in humans. We used an interspecific backcross DNA panel to map Gamt to the central region of mouse Chromosome (Chr) 10 near the locus of hesitant mutation affecting male fertility. We assigned the human GAMT gene to Chr 19 by PCR analysis of a human/rodent somatic hybrid cell line DNA panel, and further localized the human gene to Chr 19 at band p13.3 by PCR analysis of a human radiation hybrid DNA panel. Human chr 19p13.3 is homologous to the central part of mouse Chr 10 where mouse Gamt is located. Furthermore, this part of mouse Chr 10 contains mutant loci the phenotype of which is similar to the GAMT deficiency in human.