Characteristics of Mongoloid and neighboring populations based on the genetic markers of human immunoglobulins

Summary Since the discovery in 1966 of the Gm ab3st gene, which characterizes Mongoloid populations, the distribution of allotypes of immunoglobulins (Gm) among Mongoloid populations scattered from Southeast Asia through East Asia to South America has been investigated, and the following conclusions can be drawn: 1. Mongoloid populations can be characterized by four Gm haplotypes, Gm ag, axg, ab3st, and afb1b3, and can be divided into two groups based on the analysis of genetic distances utilizing Gm haplotype frequency distributions: the first is a southern group characterized by a remarkably high frequency of Gm afb1b3 and a low frequency of Gm ag, and the second, a northern group characterized by a high frequency of both Gm ag and Gm ab3st but an extremely low frequency of Gm afb1b3. 2. Populations in China, mainly Han but including minority nationalities, show remarkable heterogeneity of Gm allotypes from north to south and contrast sharply to Korean and Japanese populations, which are considerably more homogenous with respect to these genetic markers. The center of dispersion of the Gm afb1b3 gene characterizing southern Mongoloids has been identified as the Guangxi and Yunnan area in the southwest of China. 3. The Gm ab3st gene, which is found with its the highest incidence among the northern Baikal Buriats, flows in all directions. However, this gene shows a precipitous drop from mainland China to Taiwan and Southeast Asia and from North to South America, although it is still found in high frequency among Eskimos, Koryaks, Yakuts, Tibetans, Olunchuns, Tungus, Koreans, Japanese, and Ainus. On the other hand, the gene was introduced into Huis, Uyghurs, Indians, Iranians, and spread as far as to include Hungarians and Sardinians in Italy. On the basis of these results, it is concluded that the Japanese race belongs to northern Mongoloids and that the origin of the Japanese race was in Siberia, and most likely in the Baikal area of the Soviet Union.     

Distribution of immunoglobulin allotypes among local populations of Kenya olive baboons

In this paper we report on the distributions of immunoglobulin allotypes among 564 olive baboons collected at six localities in Kenya. The sample localities and sizes are 1) Lake Magadi, N = 107; 2) Nanyuki, N = 77; 3) Lake Baringo, N = 55; 4) Mosiro, N = 132; 5) Isiolo, N = 36; 6) Gilgil, N = 157. Gm allotypes 1, 10, 13, 15, and 17 are polymorphic among these samples. Gm(11) and Km(3) were present in all samples, and Gm(2,3,5,6,14,16,21,24,26) and Km(1) were absent from all samples. The proportions of individuals positive for polymorphic allotypes varied substantially between different local samples, as did the arrays and estimated frequencies of haplotypes. Allotype frequencies in local samples do not appear to be simply related to either geographic location or habitat characteristics of the localities. Our data suggest that much of the geographic variability in Kenya olive baboon populations occurs between populations separated by small geographic distances.     

The distribution of immunoglobulin allotypes in rabbit populations in Australia and on Macquarie Island

Wild rabbit populations from several parts of south-eastern Australia and from Tasmania and Macquarie Island were tested for the As1, As2, As3 ( a locus) and the As4, As5, As6, As9 ( b locus) allotypic IgG markers. All markers except As6 were present in the Australian mainland and Tasmanian populations, and there appeared to be a significant increase in As ¹ frequency with decreasing rainfall. On the other hand the Macquarie Island samples were virtually all homozygous As1 at the a locus and lacked As6 and As9 at the b locus.
These results are discussed against the background of the known history of the introduction of the rabbit into the areas studied. It was felt that 'founder effect' could account for the observed distribution on Macquarie Island. However, the As ¹ cline in Australia warrants further study, particularly in relation to possible selective effects.     

On the origin of the Chinese nation: The distribution of immunoglobulin allotypes in forty Chinese populations

Data from population and family studies show that the human immunoglobulin Gm allotypes prove to be unique genetic markers in studies of human genetics, particularly in the characterization of different race or population determined by the differences in Gm hapolotype composition and its frequency. In this paper, a total of 5,641 individuals from 40 populations were typed for Gma, f, x, b, and g factors. The genetic distances between 13 minorities (Zhuang, Uygur, Dong, Hui, Korean, Kazak, Bai, Tibetan, Mongolian, and Oroqen) and 27 Han populations were computed by Nei's method on the basis of Gm haplotype frequencies and a phylogenetic tree was constructed. The conclusions were (1) The common Gm haplotype are afb, axg, a, and ag. The Gmfb haplotype is observed only in Uygur, Hui, and Kazak. (2) There is a parallel relationship between genetic distance and geographic distance for these populations. (3) The Gmafb haplotype frequency increases sharply from north to south, and there is a concomitant sharp decrease in ag and axg frequencies. (4) A hypothesis was proposed by the author that the origin of the Chinese nation might exist in both the Yellow River and the Yangtze River region and the most likely boundary between the Southern and the Northern Chinese is near the thirty degrees north latitude.     

Genetic control of immunoglobulin allotypes in the fowl

Eight immunoglobulin allotypic specificities have been identified in the fowl by isoimmunization. Aa1 and Aa2 are controlled as codominants at the a locus, Ab1 and Ab2 at the b locus, and Ac1, Ac2, Ac3, and Ac4 at the c locus. Column chromatography and ultracentrifugation indicate that the specificities at the a locus are located on molecules corresponding to IgG with sedimentation coefficients 7 S. Immunoelectrophoresis results also indicate that we are dealing with an immunoglobulin G molecule. Further tests are underway to resolve this beyond doubt.Journal Paper No. 5405 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa. Project 1039. Supported in part by National Science Foundation Grants GB 318 and GB 4450.     

Immunoelectron microscopic localization of idiotypes and allotypes on immunoglobulin molecules

We have developed a novel approach to the analysis of antigenic (allotypic and idiotypic) determinants on intact immunoglobulin molecules. Immune complexes composed of IgG in combination with anti-idiotype or anti-allotype antibody were "visualized" by transmission electron microscopy. Individual Fab fragments of anti-idiotype or anti-allotype antibody, when bound to the IgG, altered the "Y" configuration in a reproducible and interpretable manner. Anti-idiotype antibody (either as Fab or IgG) bound to the terminus of the presumed V region of the IgG molecule, thus extending the apparent length of the Fab arms. Analysis of a rabbit VH framework allotype (a1) revealed that the determinant(s) is (are) located on the lateral portion of the V region of IgG. Binding of the anti-a1 Fab fragments was always at approximately right angles to the axis of the Fab arms of IgG. Fab antibody to the rabbit kappa light chain (b4) allotype bound to the lateral portion of the terminal half of the IgG Fab arms. This technique should be of value in localizing less well defined immunoglobulin determinants.     

Evolution of immunoglobulin allotypes and phylogeny of apes

Serum samples from 72 Pan troglodytes, 5 Pan paniscus, 22 Gorilla gorilla, 23 Pongo pygmaeus abelii, 5 Pongo pygmaeus pygmaeus, 2 hybrids P.p. abelii X P.p. pygmaeus and 13 Hylobates lar were tested for Gm(1, 2, 3, 5, 6, 10, 11, 13, 14, 15, 16, 17, 21, 24, 28), Km(1) and Bm(1, 2, 3, 4, 5, 6, 7, 8) immunoglobulin allotypes by the classical hemagglutination inhibition method. The distribution of the various alleles and phenotypes makes it possible to distinguish each species or subspecies. Common chimpanzees have the richest polymorphism. Pygmy chimpanzees share common phenotypes with gorillas. Bornean and Sumatran orangutans have their own patterns of polymorphism, as do gibbons. Our principal component plot and dendrogram are compatible with the traditional classification of Hominoidea [e.g. Simpson, Bull. Am. Mus. nat. Hist. 85: 1-350, 1945] in 3 families: Hominidae, Pongidae and Hylobatidae.     

Gene conversion in human immunoglobulin gamma locus shown by unusual location of IgG allotypes

The constant region of the gamma 1, gamma 2 and gamma 3 heavy chains of the human IgG1, IgG2 and IgG3 immunoglobulins carries antigenic determinants or G1m, G2m and G3m allotypes, which are genetic markers of these subclasses. The exceptional presence on gamma 1 and gamma 2 chains of Gm allotypes usually located on the CH3 domain of gamma 3 shows an unexpected clustering of base changes and subsequent identity of short DNA sequences in the CH3 exon of the non-allelic gamma 1, gamma 2 and gamma 3 genes. Such clusters of substitutions are not easily explained on the classical basis of point mutations. A gene conversion, which substituted a segment of the gamma 1 or gamma 2 gene with the homologous region of the non-allelic gamma 3 gene, is more likely. Other examples of possible conversion involving the gamma genes are described. The conservation or the restoration of short sequences produced by the conversion events might be related to the biological properties of the constant region of the heavy chains.     

Brief communication: immunoglobulin (Gm and Km) allotypes in two populations of Catalonia (Spain)

Serum samples from two populations of Catalonia, Spain, 208 from Olot (Gerona) and 209 from Tortosa (Tarragona), were typed for G1m (1, 2, 3, 17), G3m (5, 10, 11, 13, 14, 15, 16, 26), and Km (1). The Gm patterns of the Catalonian populations are characterized by the presence of four haplotypes, Gm 1,17;21,26 Gm 1,2,17;21,26 Gm 1,3;5,10,11,13,14,26 and Gm 3;5,10,11,13,14,26. The homogeneity for haplotype Gm 1,17;21,26 among our data and other European populations suggests the existence of an isofrequency line which starts from the Mediterranean zone of Iberian Peninsula and continues through the northwestern part of Europe. From this line a decreasing cline towards the south can be observed. For the haplotype Gm 1,2;17,21,26, affinities are observed between Catalonian populations and other populations from central Europe. This confirms the existence of a gradient towards low values from NW to SE. The presence of the typical Mongoloid haplotype Gm 1,3;5,10,11,13,14,26 is discussed in this paper. No significant differences in the frequencies of the Km1 allele were observed among the European populations.     

Distribution of hemoglobin E in several Mongoloid populations of northeast India

Nine-hundred seventy-eight subjects from eight Mongoloid tribes of northeastern India were investigated for the distribution of hemoglobin phenotypes by starch-gel electrophoresis. The sample included 157 Khasi and 24 Bodo from Cherrapunji (Meghalaya), 148, Rengma Naga and 81 Hmar of the Cachar district of Assam, 215 Adi from different subtribes, 216 Nishi, 79 Apatani, and a mixed group of 58 individuals from several other tribes of Arunachal Pradesh in northeast India. The frequency of HBB*E was found to be very low (0.01-0.02) in the Khasi, Naga, and Hmar tribes, whereas it varied from 0.06 to 0.18 among the tribes of Arunachal Pradesh. As expected, the Bodo group had a very high frequency of HBB*E (0.38), confirming earlier reports. It appears that the lack of HBB*E in the Austro-Asiatic (Khasi) and Naga-Kuki-Chin groups is probably due to the absence of malarial selection pressure as well as to isolation from their neighbors.     

The C-terminal sequences of the heavy chains of human immunoglobulin G myeloma proteins of differing isotopes and allotypes

The sequences of the C-terminal octadecapeptides obtained by cyanogen bromide cleavage of the γ-chains of myeloma proteins of the four subclasses, and a urinary heavy-chain-disease protein, have been determined. Although the sequences were markedly homologous, unique replacements were identified that distinguished between the γ_2b, γ_2c and γ_2d subclasses. The data are in accord with the postulated existence of four genetic loci or cistrons, these having arisen by the process of gene duplication.     

A genetic survey in four Mongoloid populations of the Garo Hills, India

Four Mongoloid populations, viz., Garo , Hajong , Rabha and Koch, belonging to the Tibetoburman language family of Garo Hills, India, were examined for blood types ( A1A2BO , Rh, MN), secretor factor, ability to taste PTC and cerumen types. Gene A1 is more frequent than B in Hajong and Rabha . Garo shows a higher frequency of gene B, Koch also shows a little higher frequency of gene B than A. R1 is the commonest chromosome in all the groups followed by R2. Frequency of gene M is very high in all these populations. In respect of ABH secretion in saliva, there is preponderance of the secretor gene. Incidence of non- taster gene is somewhat lower in them. Dry cerumen gene is frequent in these Mongoloid groups. In general, the Garo Hills populations show closer affinity to the Mongoloids of Northeast India in respect of gene frequencies.     

Possible existence of autoantibodies against immunoglobulin allotypes in normal rabbits, and their relation to the expression of these allotypes

The concentration of a3 allotype was increased in the serum of heterozygous a1 a3 rabbits which received antiidiotypic antibodies against anti-a3 antibodies in the perinatal period. This is explained by the normal presence of anti-a3 autoantibodies which control the expression of a3 allotype in heterozygous a1 a3 rabbits under physiological conditions.     

Sequence studies on the heavy chain of rabbit immunoglobulin A of different alpha-locus allotypes.

The amino acid sequence was determined of part of the variable region of heavy chain from rabbit immunoglobulin A of allotypes a1 and a3. Two corrections of the primary sequence of Aa1 gamma-chains are reported; most of the structural correlates of the alpha-locus allotypes are confirmed. The amino acid sequence of the N-terminal 20 residues of alpha-negative molecules was also determined and found to be homologous to the human VhIII subgroup. These molecules are present in a much higher proportion in the alpha-chain pool than in the gamma-chain.     

Anthropological studies in Assam, India. 1. Observations on five Mongoloid populations

Five Mongoloid population groups from Upper Assam (Ahom, Chutia, Deuri, Mishing and Moran) have been investigated for the distribution of anthropometric and dermatoglyphic traits as well as for that of ABO blood groups and PTC taste sensitivity. The results are discussed with special reference to extent and causes of intergroup variability.