ASSIGNMENT OF A GENE THAT DETERMINES ERYTHROCYTIC GUANOSINE-5'-TRIPHOSPHATE CONCENTRATION (GTPC) TO MOUSE CHROMOSOME-9

Nine inbred mouse strains surveyed for erythrocytic guanosine-5'-triph osphate (GTP) concentration were found to segregate into two discrete groups. Strains having low GTP levels between 1.4 and 3.4 nmol/10(9) c ells were C3H/HeJ, C3H/HeHa, A/J, and WB/ReJ. Strains having high GTP levels between 11.0 and 14.8 nmol/10(9) cells were AKR/J, DBA/2J, CBA/ J, C57BL/6J, and C57L/J. Erythrocytic ATP levels did not vary signific antly among these groups. Crosses between low and high GTP strains gav e F-1 progeny having intermediate levels of GTP, and the progeny of F- 1's backcrossed to parental strains segregated in a 1:1 ratio for GTP concentration. We designated the GTP concentration determining trait, Gtpc. Typing the C57BL/6J x C3H/HeJ (BXH) recombinant inbred strains f or GTP levels revealed 0/12 strain distribution pattern differences fo r loci on both chromosomes 5 and 9. Backcross analysis did not provide evidence for linkage of Gtpc to W (dominant white spotting) on chromo some 5 with 15/45 recombinants. A test for linkage of Gtpc to transfer rin (Trf) on chromosome 9 gave evidence of linkage with an observed re combination frequency of 14.6 +/- 5.5 and a 99% confidence interval of 3.9-33.9 cM.