- A total of 902 plasma samples from the Rambouillet, Targhee,
Columbia, Lincoln, and Suffolk breeds of sheep were analyzed for
transferrin type by disc electrophoresis.
Six transferrin types, Tf[superscript A], Tf[superscript B], Tf[superscript C], Tf[superscript p], Tf[superscript E], and Tf[superscript P],
were found in the Rambouillet,
Targhee, and Columbia breeds while five, A, B, C, D, E, and four,
A, B, C, D, types were observed in the Suffolk and Lincolns respectively.
Mating data involving five of the six alleles confirmed
previous reports that the transferrins are inherited as co-dominant
autosomal allelic genes.
No evidence was found to support a previous suggestion of maternal-fetal incompatibility expressed as a
disturbed segregation ratio.
Gene frequencies were calculated for breeds and strains within breeds.
It was shown that there were characteristic breed frequencies but they could not be used to predict the degree of relationship between breeds. An excess of homozygotes was observed in the Rambouillet, Targhee, and Columbia breeds which was
probably due to inbreeding and subdivision of the population.
Characteristic frequencies were observed for inbreds, linecrosses, and
control lines within breeds.
The frequency of the B allele was much lower in the Rambouillet, Targhee, and Columbia breeds of the U. S. Sheep Experiment Station at Dubois, Idaho, than in the Suffolk and Lincoln breeds
of western Oregon.
Since the Dubois Station differs considerably
from western Oregon in severity of climate, altitude, management,
plane of nutrition, and incidence of various diseases, it was suggested that the B allele might be at a disadvantage in higher altitudes
with a more severe climate and a higher incidence of disease such as
that present at the Dubois Station.
The effect of transferrin type on some pre-weaning and yearling performance traits was found to be significant for birth weight
and average daily gain from birth to weaning.
The effect of transferrin type on weaning weight and grease fleece weight, although not
statistically significant, closely approached significance.
weaning nor yearling indices were significantly different among alleles.
Since selection is by the index method in the sheep population
at the Dubois Station, it was suggested that artificial selection has little or no effect on frequency of transferrin alleles in these