Subdivision of the allele Tfd for transferrins in Holstein and Ayrshire cattle.

ENETICALLY controlled differences in the p-globulins of British breeds of Gdairy cattle have been described by SMITHIES and HICKMAN (1958) and ASHTON (1958). GIBLETT, HICKMAN and SMITHIES (1959) showed that these ,@globulins are transferrins. The same transferrin differences have been described in Swedish cattle (GAHNE, RENDEL and VENGE 1960) and in Danish cattle ( H~JGAARD, MOUSTGAARD and M ~ L L E R 1960). Serum protein polymorphisms in several species have been reviewed by OGDEN (1961). Plasma protein polymorphisms in man have been reviewed by HARRIS (1961 ) . In these populations three alleles Tf“, TfD, and TfE, have been observed to control the synthesis of transferrins A, D and E (TfA, TfD and TfE) , respectively. Each transferrin migrates in starch gels as four discrete proteins (ASHTON 1959a). Two additional alleles (Tf” and TfF) have been observed in Zebu cattle but not in Jersey, Hereford or Shorthorn cattle ( ASHTON 1959a). Recent developments in starch gel electrophoresis techniques have enabled us to detect differences among individuals possessing the TfD allele ( KRISTJANSSON 1962). This report describes these differences and presents evidence which indicates that the former TfD allele is, in fact, two alleles which produce different transferrins which were indistinguishable using the original starch-gel electrophoresis procedures.