Strain distribution and linkage relationship of a mouse embryonic hemoglobin variant

Search for structural variants of three globin chains (x, y, z), synthesized only during mouse embryonic hematopoiesis, was carried out by electrophoretic analysis of blood from 12-day embryos, all with C57BL/6 mothers, and fathers from 115 inbred stocks selected for their diverse genetic origins. Structure of the beta-chains of adult hemoglobins differed among the tested strains, with 57 carrying the Hbbs allele, 56 the Hbbd allele, and two the Hbbp allele. The search revealed no x- or z-chain variants but confirmed and extended knowledge of a previously described y-chain variant. Blood of all embryos sired by males from the 57 Hbbs strains contained only y'-chains, while blood of au embryos sired by Hbbd or Hbbp males contained y2-chains as well as the y1-chains inherited from their C57BL/6 mother. The locus controlling structure of the y-chain of mouse embryonic hemoglobins is thus extremely closely linked to the locus controlling structure of adult hemoglobin beta-chain, with maximum possible recombination frequency less than 0.019.