Gc Protein variation work

The distribution of Gc subtypes among the mongoloid populations.

1: Am J Phys Anthropol. 1980 Nov;53(4):505-8.Links
Matsumoto H, Matsui K, Ishida N, Ohkura K, Teng YS.
The polymorphism of Gc (group-specific components) has been investigated for a series of 3,160 individual samples from 11 Mongoloid populations in Asia and North and South America by isoelectric focusing on polyacrylamide gels. The samples fall into six Gc phenotypes which can be explained by the three common alleles, Gc1F, Gc1S, and Gc2, together with several variant phenotypes explained as the heterozygotes for the three common alleles. The distribution of Gc1F suballele appears to be considerably different from population to population among Mongoloids, ranging from 0.105 (Machiguenga Indians, Peru) to 0.609 (Kadazan, Borneo). A clear geographic cline from Southeast Asia into South America in Gc1F allele was observed in the populations. In general, Gc1F allele frequencies are lower in European populations and higher in African populations. The range of variability in the Gc1F values observed among the Asiatic populations is between the Africans and the Europeans.

Distribution of group-specific component (Gc) subtypes in several Mongoloid populations of East Asia.

Saha N. / Ann Hum Biol. 1989 Jan-Feb;16(1):53-60.Links
Department of Biochemistry, Faculty of Medicine, National University of Singapore.
The distribution of group-specific component (Gc) subtypes was determined by isoelectric focussing in thin layer polyacrylamide gels of pH range 4 to 6.5, in a group of 2412 individuals from 10 Mongoloid populations of East Asia. The sample comprised 959 Chinese from different localities (Singapore, 249; Malaysia, 347; Taiwan, 246; Hong Kong, 57; Fuzhou mainland, 60), 338 Koreans, 277 Filipinos, 484 Thais, 330 Malays and 24 Indonesians. The Filipinos and Malays had lower frequencies of Gc2 (0.15 and 0.18) compared to other Mongoloid populations (0.23 to 0.32) and the Chinese (0.24 to 0.32). The frequencies of Gc1F varied from 0.39 to 0.49 in the Chinese and 0.35 to 0.52 in other Mongoloid populations. Low frequency of rarer variants was observed in most of the populations. The average frequency of Gc2 was higher in the Japanese (0.26 +/- 0.01) than in the Chinese (0.24 +/- 0.02), and in Mongoloids of East Asia (0.23 +/- 0.01) and South-East Asia (0.17 +/- 0.01). The average frequencies of Gc1F and Gc1S were similar in the Chinese and Japanese, whereas the Mongoloids of South-East Asia had a much higher frequency of Gc1F and a lower frequency of Gc1S than the Chinese, Japanese and East Asian Mongoloid populations.

Distribution of group-specific component/vitamin-D-binding protein subtypes in Saudi Arabia.

Hum Hered. 1991;41(1):53-6. Degheishem SM, Sedrani SH, Van Baelen H, Bouillon R, Duhaiman AS. Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.

The distribution of group-specific component (Gc) phenotypes and the Gc allele frequencies were investigated in 1,082 individuals from five different provinces of Saudi Arabia by the combined use of isoelectric focusing and immunofixation. Between provinces variations in the Gc allele frequencies were found. Gc1S decreased and Gc1F increased from the northwest to the southeast in Saudi Arabia. The overall frequencies in Saudi Arabia were 0.236 for Gc1F, 0.610 for Gc1S, 0.150 for Gc2 and 0.004 for rare alleles. The observed frequencies did not differ significantly from those found in other population samples from the Middle East. In nine samples rare Gc variants were found.
PMID: 2050383 [PubMed - indexed for MEDLINE]

Population distribution of the human vitamin D binding protein: anthropological considerations.

Am J Phys Anthropol. 1985 Sep;68(1):107-22. / Constans J, Hazout S, Garruto RM, Gajdusek DC, Spees EK.

The polymorphism of the serum vitamin D binding protein (DBP) in humans is based on the existence of three common alleles, Gc1F, Gc1S, and Gc2, and 84 rare alleles. The geographical distribution of Gc1F, Gc1S, and Gc2 alleles shows north to south clines, together with a balanced equilibrium between the Gc1F or Gc1S allele frequency and the Gc2 frequency. The distribution of the FST values shows high variability within a geographical area. For European and North Asiatic groups, the FST values are the lowest observed, and the reason may be a long process of homogenization. Aboriginal populations from Australia and New Guinea and groups from both North Africa and South America show the greatest heterogeneity of their allele frequencies. Systematic factors such as genetic drift and selection may account for this distribution. In contrast with the three main DBP alleles, the distribution of the rare alleles corresponds to patterns of human migrations that occurred during prehistoric and historic periods. Thus, the rare mutants are of particular relevance to anthropological and genetical investigations.
PMID: 4061596 [PubMed - indexed for MEDLINE]

Polymorphism of group specific component (Gc) in nine Han subpopulations in China
[Article in Chinese]

Yi Chuan Xue Bao. 1997;24(6):483-91. Xu J, Tan Q, Du R.
Institute of Genetics, Chinese Academy of Sciences, Beijing.
Isoelectric focusing (IEF) followed by immunofixation in thin layer polyacrylamide gels (pH4-6) was used to analyse the Gc subtypes of 1841 individuals from nine Han geographically distributed populations in China. The Gc1F gene frequencies in these Han subpopulations from Lanzhou, Huhhot, Harbin, Xi'an, Zhengzhou, Chengdu, Guiyang, Zhangzhou and Harras in Guangdong Province were 0.3905, 0.4333, 0.4193, 0.4146, 0.4182, 0.4035, 0.4045, 0.4381 and 0.4347 respectively; Gc1S were 0.3071, 0.2190, 0.2734, 0.2261, 0.2182, 0.2871, 0.2889, 0.2738 and 0.2764 respectively; Gc2 were 0.2786, 0.3357, 0.2917, 0.3367, 0.3295, 0.2896, 0.3065, 0.2667, and 0.2814 respectively. GcV were 0.0238, 0.0119, 0.0156, 0.0226, 0.0341, 0.0198, 0.0000, 0.0214 and 0.0075 respectively. The results of present study indicated a clear cline of linear change from north to south China in allelic frequency at the Group-Specific Component (Gc) locus among nine Chinese populations. Three alleles, Gc1F, Gc2 and GcV, showed frequencies varying from 0.3905 to 0.4381, from 0.2786 to 0.3367 and from nil to 0.0341, respectively, over these geographical subpopulations. In addition, some rare variant phenotypes of Gc in Chinese populations were discussed.
PMID: 9575657 [PubMed - indexed for MEDLINE]

An improved method for the identification of Gc1 subtypes (group-specific component) by isoelectric focusing.

Vox Sang. 1978;35(6):401-4.
Kühnl P, Spielmann W, Loa M.
The occurrence of common subtypes of the Gc1 gene in a German population (n = 261) was investigated by isoelectric focusing on thin layers of polyacrylamide in the pH range 4-6. Six common phenotypes designated Gc 1S, 1F, 1F-1S, 2-1S, 2-1F, and 2 are considered as gene products of three common alleles with the following frequencies: Gc1S=O.603, Gc1F=0.125, and Gc2=0.272. The sum of the allele frequencies of Gc1S and Gc1F corresponds with that of the 'old' Gc allele. Family investigation are in agreement with an autosomal codominant way of inheritance. the method employed provides an identification of the subtypes within 4 h without using anti-Gc-serum for immunoprecipitation.
PMID: 746633 [PubMed - indexed for MEDLINE]

Hum Genet. 1978 Feb 23;41(1):53-60.
Analysis of the Gc polymorphism in human populations by isoelectrofocusing on polyacrylamide gels. Demonstration of subtypes of the Gc allele and of additional Gc variants.

Constans J, Viau M, Cleve H, Jaeger G, Quilici JC, Palisson MJ.
For the study of the group-specific component (Gc) system, serum samples were examined by polyacrylamide gel electrophoresis and by a newly developed immunofixation isoelectrofocusing procedure. Thereby, a greater extent of polymorphic variation was revealed than was known previously. The allele Gc1 could be subdivided into the alleles Gc1F and Gc1S. The distribution of Gc1 subtypes was very different in three populations (Pygmies, Amerindians, and Pyreneans) examined. New variants of the Gc1 and Gc2 genes were also described in the Amerindians and in the Pygmy population, respectively.
PMID: 75833 [PubMed - indexed for MEDLINE]

Hum Hered. 1979;29(4):242-9.Links
Group-specific component (Gc) 'subtypes' of Gc1 by isoelectric focusing in US blacks and whites.

Kueppers F, Harpel B.
Isoelectric focusing was applied to the Gc polymorphism. In agreement with Constans et al., we found two common 'subtypes' of Gc1 that could not be identified by conventional electrophoretic procedures. They are labeled Gc1F and Gc1S. Gc1F has a slightly lower isoelectric point than Gc1S. In groups of US blacks the allele frequencies were for Gc1F; 0.732 and for Gc1S; 0.147. In whites these figures were 0.149 and 0.572. We also found GcAb in blacks with a frequency of 0.015. The concentrations in serum of Gc protein as measured by radial immunodiffusion did not differ according to phenotype.
PMID: 90007 [PubMed - indexed for MEDLINE]

Hum Genet. 1981;59(1):72-4.
Group-specific component (Gc) subtypes in the Chinese population of Hong Kong.

Kwok KY, Lewis WH.
Institute of Medical and Health Care, Hong Kong Polytechnic, Hung Hom, Kowloon, Hong Kong.
The distribution of Gc subtypes in a sample of the Chinese population of Hong Kong was studied using isoelectric focusing followed by immunofixation. A sensitive modification of this technique is described. Nine distinct phenotypes were observed which appear to result from the three common alleles Gc1F, Gc1S, and Gc2, which are found in most populations. The respective gene frequencies were 0.494, 0.258, and 0.247. In addition, two rare phenotypes were observed which appear to be due to a rare allele tentatively identified as Gc2C2.
PMID: 10819026 [PubMed - indexed for MEDLINE]

Am J Phys Anthropol. 1980 Mar;52(3):435-41.Links
Gc (vitamin D binding protein) subtype polymorphism and variants distribution among Saharan, Middle East, and African populations.

Constans J, Lefevre-Witier P, Richard P, Jaeger G.
This article presents the results obtained by electrophoretic analysis of the group specific component polymorphism in more than 1,250 serum samples from populations living in the Sahara, the Middle East, and equatorial Africa. In addition to the alleles Gc1F and Gc1s, five variants, including one previously unknown, were found. The distribution of the alleles herein described permits speculation on exchanges and relations among the groups considered. The lowest frequencies of the gene Gc2 correspond to regions where sunlight is stronger. There is also a north-south gradient in the Gc1F gene frequency. This seems to parallel the gradient seen in skin pigmentation.
PMID: 6155786 [PubMed - indexed for MEDLINE]

Hum Genet. 1984;67(4):378-84.Links
Population genetics of the vitamin D binding protein (GC) subtypes in the Asian-Pacific area: description of new alleles at the GC locus.
Kamboh MI, Ranford PR, Kirk RL.
Isoelectric focussing (IEF) in thin layer polyacrylamide gels pH range 4-6.5 has been used to analyse the GC phenotypes of 4233 individuals from 28 different population groups in the Asian, Pacific, and Australian area. Because this technique reveals subtypes of the common GC*1 allele, there is almost a two-fold increase in the mean heterozygosity at the GC locus using IEF compared with conventional electrophoresis. The highest frequency (above 50%) of the GC*1S allele was encountered in Indian populations, reflecting genetic affinities with Europeans. By comparison, east and south east Asians are unique offing maximum values of the GC*1F allele (50%). With the exception of a few Pacific populations which show similar frequencies to east Asians, all other groups in the Pacific area, including Australia, have values of GC*1F similar to GC*1S ranging from 27% to 40%. The GC*2 frequency in most populations varies from 20% to 30%. However, some Polynesian groups have values up to 40% and Australian Aborigines less than 10%. Among other alleles, GC*1A1 is found to be widely distributed among Australian Aborigines and Melanesians and occurs sporadically in Polynesians, Micronesians, and in the Lesser Sunda Islands. Four new alleles, GC*1C24, GC*1C35 Aborigine, GC*1A21, and GC*1A22 are described. The gene frequency data at the GC locus has been used to calculate Nei genetic distances between the populations studied.
PMID: 6541632 [PubMed - indexed for MEDLINE]

Hum Genet. 1981;59(1):75-6.Links
Gc subtyping in Malaysians and in Indonesians from north Sumatra.

Tan SG, Gan YY, Asuan K, Abdullah F.
Department of Biology, Universiti Pertanian Malaysia, Serdang, Selangor, Malaysia.
Malays, Chinese and Indians from peninsular Malaysia; Ibans and Bidayuh from Sarawak state, Northern Borneo; and Bataks, Minangkabau and Javanese from North Sumatra, Indonesia, were subtyped for Gc (group-specific component) by polyacrylamide gel isoelectric focusing. All eight populations investigated were found to be polymorphic for three common alleles, Gc1F, Gc1S and Gc2.
PMID: 10819027 [PubMed - indexed for MEDLINE]

Hum Hered. 1983;33(1):5-8.Links
Gc subtypes in Icelanders.

Karlsson S, Skaftadóttir I, Arnason A, Thórdarson G, Jensson O.
Isoelectric focusing was used to determine the frequencies of Gc subtypes in Icelanders. The gene frequencies observed were Gc1F = 0.107, Gc1S = 0.631 and Gc2 = 0.262. An Icelandic Gc variant allele (Gc Iceland) is shown to have a different isoelectric point from the variant allele Gc-Norway. Gc-Iceland has been detected in 3 unrelated individuals giving the allelic frequency of 0.004 in the Icelandic population. Studies of 65 mother-child pairs confirm the assumed three-allelic mode of inheritance.
PMID: 6840779 [PubMed - indexed for MEDLINE]

Z Rechtsmed. 1980 Jan;84(2):95-7.Links
Distribution of Gc-subtypes in Western Germany (Düsseldorf region).

Scheil HG, Driesel AJ, Röhrborn G.
Gc-subtypes were determined by isoelectric focusing and immunofixation on samples from 1157 unrelated individuals. The frequency of the three genes was found to be Gc1S 0.5476, Gc1F 0.1561, Gc2 0.2963. A rare allele, GcVI, was observed.
PMID: 7376746 [PubMed - indexed for MEDLINE]

Variations in the vitamin D-binding protein (Gc locus) and risk of type 2 diabetes mellitus in French Caucasians .
Metabolism , Volume 50 , Issue 3 , Pages 366 - 369 W . Ye
Abstract
Electrophoretic variants of the vitamin D-binding protein (DBP) have been reported to be associated with type 2 diabetes mellitus (DM) or with prediabetic phenotypes in several non-Caucasian populations. Two frequent missense polymorphisms at codons 416 (Asp → Glu) and 420 (Thr → Lys) are the genetic basis for the 3 common electrophoretic variants of DBP (Gc1F, Gc1S, and Gc2) and the resulting circulating phenotypes (Gc1F/Gc1F, Gc1F/Gc1S, Gc1S/Gc1S, Gc1F/Gc2, Gc1S/Gc2, and Gc2/Gc2). In this study, we investigated the association of these polymorphisms with type 2 DM in French Caucasian subjects. Variations at codons 416 and 420 were examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Allele frequencies at both codons did not differ in type 2 DM patients and in control subjects (Asp416: 42.4% v 46.2%, respectively, P = .33; Lys420: 25.5% v 29.0%, respectively, P = .31). Distribution of genotypes at both codons, of the haplotypes defined by the 2 codons, and of the DBP phenotypes defined by the haplotypes were also similar in diabetic and control subjects. In conclusion, our study suggests that genetic variants of the DBP gene are not associated with the susceptibility to type 2 DM in French Caucasians.

Ethnic variation in vitamin D-binding protein (GC): a review of isoelectric focusing studies in human populations
M. I. Kamboh and R. E. Ferrell. Hum Genet (1986) 72:281-293 Link

"A marked variation in common GC suballele frequencies in different geographic areas seems to correlate with skin pigmentation and intensity of sun light. Pigmented (black) and keratinized (yellowish) skin type populations have a relatively high frequency of the GC*IF allele as compared to white skin populations. By comparison non-pigmented and non-keratinized white skin populations are generally characterized by having the maximum values of the GC*IS allele."

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