Embryonic ε chains of mice and rabbits

THE existence of an embryonic α-type globin chain (χ or ζ) in early embryos of mice and rabbits has been described 1–3 . A similar ζ chain can be found in humans 4,5 . Here we present data on the structure of the embryonic β-type ε chains of mice and rabbits. In mice, three embryonic haemoglobins, Hb EI, EII and EIII have been described. These haemoglobins consist of four globin chains, namely the embryonic χ, εy and εz chains and the adult α chain 3,6–8 . Hb EI has the structure χ 2 εy 2 , Hb EII is α 2 εy 2 and Hb EIII is α 2 εz 2 . The χ chain is an embryonic α-type chain 1,2 . We find six haemoglobin fractions in nucleated embryonic erythrocytes of the rabbit. Three of the haemoglobins (Hb EI–EIII) do not contain α, but χ chains like Hb EI of the mouse; the other three (Hb LI–III) are similar to mouse Hb EII and EIII 1 .