Heterozygosity and ethnic variation in Japanese platelet proteins

Abstract

Sixty-two polypeptides visualized on silver-stained two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) preparations of platelets from 85 Japanese subjects, in total 5,252 spots, have been scored for genetic variation. Inherited variants of 11 of the polypeptides were recognized; the index of heterozygosity was 2.4% +/- 0.2%. Thus far, 10 genetic polymorphisms identified by 2-D PAGE of plasma, erythrocytes, or platelets have been identified in both Japanese and Caucasian subjects. A comparison of allele frequencies reveals four significant ethnic differences. We also observed four polypeptides exhibiting a low frequency polymorphism in one group but not in the other, as well as three polymorphisms in Caucasians for which no counterpart polypeptide has thus far been recognized in the Japanese group and, vice versa, 11 such polymorphisms in Japanese. Although a similar comparison of 7 enzyme polymorphisms studied with one-dimensional electrophoresis (1-D E) in the same populations revealed a relatively higher number of significant ethnic differences, evidence is presented that this is due primarily to the greater number of 1-D E observations entering into the calculation. It is argued that this similarity in the frequency of ethnic differences among the polypeptides studied by 2-D PAGE and by 1-D E is further evidence that the proteins revealed by 2-D PAGE do not differ greatly in their response to the interplay of mutation, selection, and drift from those revealed by 1-D E studies of plasma proteins and erythrocyte enzymes.

Average locus differences in mutability related to protein "class": a hypothesis.

“…This ability has been further documented for variants of transferrin (2), L-glycerol-3-phosphate dehydrogenase (3), a1-antitrypsin (4), and esterase D (5,6). In our laboratory, we could readily detect with 2-D gels 8 out of 12 variants first identified with 1-D E, representing allele products offive loci (7).…”

Characterization of a 28-kD Polymorphic Polypeptide Detected by Two-Dimensional Electrophoresis of Human Platelets

“…However, the ThA polypeptide pattern was unaffected by these factors. In relation to pre vious reports on the polymorphisms of plate let polypeptides we have concluded that the ThA polypeptide corresponds with the C-14 polypeptide of Asakawa et al [7] and the PL-5 polypeptide of Hanash et al [5], and we have tried to characterize the polypeptide in more detail.…”