Regional localization of the human genes for S-adenosylhomocysteine hydrolase (cen?q131) and adenosine deaminase (q131?qter) on chromosome 20

Abstract
The gene loci for S-adenosylhomocysteine hydrolase (AHCY) and adenosine deaminase (ADA), two enzymes with related metabolic functions, have both been assigned to human chromosome 20. We have used rodent-human somatic hybrids containing translocations involving human chromosome 20 to more precisely determine the relative locations of the AHCY and ADA loci. Our results assign the AHCY locus to the long arm of chromosome 20, in the region cen→q131, and ADA to the region q131→qter.