Trommershausen-Smith A, Suzuki Y
Anim Blood Groups Biochem Genet. 1978;9(2):97-104. doi: 10.1111/j.1365-2052.1978.tb01419.x.
A family study of an index case in the Arabian breed of horses demonstrated the presence of a new allele in the prealbumin (Pr) system of electrophoretically determined markers in horse serum which, when homozygous, results in the absence of any recognizable zones in the Pr region. The symbol PrO is proposed for this allele which has an estimated frequency in Arabian horses of 0.09.