MAPPING OF THE HOMOTHALLIC GENES, HMα AND HM a, IN SACCHAROMYCES YEASTS

Abstract

ABSTRACT Two of the three homothallic genes, HMα and HM  a, showed direct linkage to the mating-type locus at approximately 73 and 98 stranes (57 and 65 centimorgans [cM]), respectively, whereas, the other, HO, showed no linkage to 25 standard markers distributed over 17 chromosomes including the mating-type locus. To determine whether the HMα and HM  a loci located on the left or right side of the mating-type locus, equations for three factor analysis of three linked genes were derived. Tetrad data were collected and were compared with expected values by X2 statistics. Calculations indicated that the HMα gene is probably located on the right arm at 95 stranes (65 cM) from the centromere and the HM  a locus at approximately 90 stranes (64 cM) on the left arm of chromosome III.