The chromosomal localization of the chicken transferrin receptor gene,
as well as sequences that were homologous to the viral oncogene v-fos
and the human gene families ZFY and SRY were determined by the method
of nonisotopic DNA-DNA in situ hybridization. A correspondence was re
vealed between the Comptonian linkage group 10 and chromosome 1. A com
mon origin of avian chromosome Z and mammalian chromosome Y is hypothe
sized.