“…During male meiosis the chromosomes receive an imprint which permits them to be recognised in the embryo as paternally derived chromosomes (Grouse, 1960(Grouse, , 1966(Grouse, , 1977. In the cytoplasm of the zygote there must exist a second mechanism for the recognition of these imprinted chromosomes and which causes their elimination during the fifth to ninth cleavages of the zygote nuclei (DuBois, 1933;Crouse, 1960;Rieffel and Grouse, 1966). The sepia mutation could exert its effects by modifying one, or both, of these mechanisms.…”