Mapping the hemoglobin locus in mice transmitting the flecked translocation.

HIS report describes the chromosomal location of the hemoglobin beta-chain Tstructural locus (Hbb) in mice transmitting the flecked ( f d ) translocation (CATTANACH 1961 ), and the electrophoretic behavior of hemoglobins analyzed by acrylamide gel and cellulose acetate systems. In adult mice, the electrophoretic difference in hemoglobin determined by the locus behaves as a unit character ( GLUECKSOHN-WAELSCH, RANNEY and SISKEN 1957). Alleles are Hbbs (single-type hemoglobin) and Hbbd (diffuse-type hemoglobin). More recently a third allele. HbbP, was reported by MORTON (1962). The structural relationship of Hbbp to Hbb* and Hbbd, and the nature of its polypeptide chains has not been determined. Hbbd is probably compound and may represent adjacent structural loci for two kinds of polypeptide chains, beta and delta, whereas Hbbs represents the structural locus (i) for a single kind of polypeptide chain, beta (HUTTON et al. 1962a, b). Evidence by RIGGS (1965) and MORTON (1966) suggests that dimerization of beta chains may account at least in part for the single-diffuse electrophoretic phenomenon. The flecked translocation is an insertion of an autosomal segment carrying the wild-type alleles of albino ( c ) and pink-eyed dilution ( p ) , from linkage group I into the X (sex) chromosome ( CATTANACH 1961 ; OHNO and CATTANACH 1962). It is nonreciprocal and no recombination has been observed between the insertion and homologous autosomal segments. The insertion is viable with or without the deletion in females and relatively inviable without the deletion in males. Female mice having the X-autosome insertion and carrying p or c in homozygous or hemizygous condition in Autosome I exhibit varied degrees of color mosaicism. Males of similar genotype are wild type in color. The location and behavior of c and p loci in the insertion in the X chromosome (CATTANACH 1961; LYON 1963; OHNO and CATTANACH 1962) are generally consistent with the inactive-X hypothesis (LYON 1961) as modified by RUSSELL (1963). Hbb is located close to c and still closer to shaker-1 ( sh I ) in the order Hbb, sh-1, c in linkage group I (POPP and ST. AMAND 1960; POPP 1962). The best estimates of recombination from combined data for the Hbb to c interval are 7.3 * 0.75% in females and 3.5 C .79% in males (POPP and ST. AMAND 1964) ; for the Hbb to sh-1 interval 1.4 * .42% in females and 2.0 * 0.51% in males (POPP 1962). Pink-eyed dilu-