MOLECULAR MAPPING OF SSRS FOR PGM1 AND C8B IN THE VICINITY OF THE RATFATTY LOCUS

Recessive mutations at the rat fatty locus (fa, fa(cp)), which produce obesity, insulin resistance, and diabetes, provide useful experimenta l models for similar phenotypes in humans, The molecular pathogenesis of the metabolic phenotype in animals segregating for fa is unknown an d difficult to study once the confounding metabolic effects of obesity are present. Although various experimental methods distinguish preobe se from lean rats (phenotypic markers and molecular markers geneticall y linked 60 fatty), technical difficulties limit their utility, We rep ort the identification of two (GT)(n) simple sequence repeats (SSRs) n ear the rat phosphoglucomutase gene (Pgm1) gene and two SSRs, (GA)(n) and (GT)(n), near the rat complement component 8 beta gene (C8b). Thes e SSRs map to an similar to 4-cM interval flanking the fatty locus on rat chromosome 5, Use of these molecular markers in combination offers an improved method for early assessment of gene dosage for fa and hen ce for studying the fundamental molecular physiology underlying the de rangements of metabolism and behavior resulting from mutations in this gene. (C) 1995 Academic Press, Inc.