The polymorphism of the vitamin D-binding protein (Gc); Isoelectric focusing in 3 M urea as additional method for identification of genetic variants

Abstract

Since the last report numerous new DBP (Gc) variants have been observed; at present a total of 84 different mutants can be distinguished. Several of them have similar electrophoretic mobilities and/or isoelectric points of conventional isoelectric focusing (IEF). IEF in polyacrylamide gels in the presence of 3 M urea is a convenient and efficient method for the detection of hidden variation.

Products of two common alleles at the locus for human placental alkaline phosphatase differ by seven amino acids.

“…Whatever the phenomenon involved, it seems likely that it also accounts for the remarkable number of amino acid substitutions between the two common alleles described here. It is noteworthy that the protein products of two common alleles at the locus coding for the vitamin D binding protein of human serum (GC) have been reported to differ by four amino acid substitutions (23,24) and that in this case also an extensive series of rare alleles has been identified in population surveys using electrophoresis or isoelectric focusing (25,26).…”

Group-specific component (Gc) subtypes in two chinese populations

“…Gc IA8 and Gc 2A4 which have been well known in Japanese (Constans and Cleve, 1979;Matsumoto et aI., 1980;Shibata, 1983;Omoto, 1986), were also detected in the present study. The other variant, Gc 1C18, was hitherto known also in Japanese (Constans et al, 1983;Shibata, 1983).…”

“…Using this technique, approximately 50,000 individuals from more than 160 different populations have been tested for the Gc polymorphism, making this system one of the most intensively studied among human blood genetic markers (Kamboh and Ferrell, 1986). Besides the universally common alleles, Gc*IF, Gc*IS and Gc*2, the number of variant alleles at the Gc locus now exceeds 85 (Constans et al, 1983;Nakasono et al, 1985).…”

Isoelectric focusing of vitamin D binding protein (Gc): Genetic diversity in the populations of Iran

“…The Gc*l allele was shown to consist of two suballeles Gc*IS and Gc*IF, thus giving three common alleles (Gc*2, Gc*IS and Gc*IF) instead of the conventional two (Gc*l and Gc*2). More than 82 rare alleles have also been described by conventional IEF and by an improved method of IEF using polyacrylamide gels containing 3 M urea (Constans et al, 1983). The frequencies of the Gc*IS and Gc*IF suballeles in populations of various racial origins and the localisation of some rare variants in certain regions and ethnic groups suggest that Gc is a useful marker for human taxonomic studies (Papiha et al, 1982a;Novo and Cleve, 1983).…”