New data for AG haplotype frequencies in Caucasoid populations and selective neutrality of the AG polymorphism.

We present the results of AG antigen typings of three Caucasoid population samples: Lebanese, Tunisians, and Finns. AG haplotype frequencies estimated by maximum-likelihood methods are compared with the frequencies observed in 13 world populations previously tested for AG specificities by computing a genetic distance matrix used in a multivariate analysis. A high degree of polymorphism characterizes the three samples, with 10 haplotypes detected in the Lebanese and 11 haplotypes detected in the Tunisians and Finns; high heterozygosity levels are also present in the three populations. The genetic distance analysis shows that the three populations possess a genetic structure intermediate between those observed in sub-Saharan Africans and in Caucasoids from the Near East and India. This tight correspondence between AG differentiation and geography is confirmed by a highly significant correlation coefficient found between genetic and geographic distances computed worldwide, suggesting that an isolation by distance model of evolution applies to the AG system. The Ewens-Watterson test for selective neutrality on all world populations tested for AG specificities also supports the hypothesis that the AG system behaves like a neutral polymorphism. Overall, the AG differentiation pattern appears to be close to the patterns observed for other serological polymorphisms, such as RH, GM, and HLA, whose evolutionary mechanisms are also discussed.

A worldwide population study of the Ag-system haplotypes, a genetic polymorphism of human low-density lipoprotein.

The aim of this investigation is to examine the distribution of the Ag immunological polymorphism in human populations on a worldwide scale and to look for possible explanations of this distribution in the field of modern human peopling history and Ag-system evolution. Extensive Ag-antigene typings were carried out on 13 human population samples, including sub-Saharan African, European, west and east Asiatic, Melanesian, Australian aborigine, and Amerindian groups. Complete Ag-haplotype frequencies were estimated by maximum-likelihood-score procedures, and the data were analyzed by genetic distance computations and principal coordinate projections. With the exception of the Amerindian sample, the Ag polymorphism is shown to be highly polymorphic in all the populations tested. Their genetic relationships appear to be closely correlated to their geographical distribution. This suggests that the Ag system has evolved as a neutral or nearly neutral polymorphism and that it is highly informative for modern human peopling history studies. From the worldwide Ag haplotypic distributions, a model for the Ag molecular structure is derived. According to this model and to the most recent results obtained from molecular data, the establishment of the Ag polymorphism could be explained by several mutations and recombination events between the haplotypes most frequently found in human populations today. As a conclusion, genetic and paleontological data suggest that the genetic structure of caucasoid populations (located from North Africa to India) may be the least differentiated from an ancestral genetic stock. Worldwide genetic differentiations are properly explained as the results of westward and eastward human migrations from a Near East-centered but undefined geographical area where modern humans may have originated. The importance of Ag polymorphism analyses for the reconstruction of human settlement history and origins is discussed in the light of the main conclusions of the most recent genetic polymorphism studies.

Study of five haemogenetic markers (Gc, C3, Bf, Ag, and GALT) in six Indonesian populations and in 12 subgroups of Balinese.

In various ethnic groups of the Indonesian archipelago and of Bali, the polymorphisms of the serum proteins Gc globulin (vitamin D-binding protein), C3 (complement component 3), Bf (complement factor B), Ag x,y (lipoprotein allotypes), and of the red cell enzyme system GALT (galactose-1P-uridyltransferase) were analysed. Among the studied proteins, the Gc system was the most informative one for the anthropologist. Besides considerable differences of frequencies of the common alleles Gc*1F, Gc*1S and Gc*2, a number of rare alleles (1A1, 1A3, 1A8, 1A9, 1A12, 1C2, 1C21, 1C24, and 2C8) and some new ones (1C28, 1C29, 1C30, 2C9) were observed. The presence of Gc*1A1 demonstrates the relationship to the Australo-Melanesian populations, but Mongolian variants (1A3, 1A8, 1A9, 1C2) were also encountered. Within the C3 system a very high frequency of the C3*S allele was observed in all populations. The rare alleles C3*F0.55, C3S1, and C3*S0.5 were observed in some groups. A new allele (C3*F0.35) was detected in a Chinese individual and in a nobleman from Bali. The frequency of the Bf*F allele was rather low in general, and the Bf*S0.7 allele was found in three Indonesian individuals only. The Ag*(x) frequencies were rather high, as it is known for Asiatic populations. Variability among subgroups was not very pronounced. The GALT*2 allele (Duarte variant of the enzyme) was observed very rarely; however, it was present in several populations. Enzyme activities could not be determined, and therefore we cannot tell whether the galactosaemia gene (GALT*0) was present or not.

Serum protein polymorphism in Bali (Indonesia).

Serum samples from Bali, obtained in three different ethnic groups and in one isolated village were tested by isoelectric focusing electrophoresis for Gc, Pi, Tf and Hp subtyping. In addition to the three common alleles Gc1F, Gc1S and Gc2, two variants Gc1A1 and Gc1A8 were observed. In the Pi system, five alleles were present: PiM1, PiM2, PiM3, PiM4 and PiX. The Tf variability was exceptional with the presence of eight alleles: TfB1, TfC1, TfC2, TfC3, TfC4, TfC8, TfD1 and TfDchi. For Hp, there were two common alleles Hp1S and Hp1FS and two rare ones: Hp1F and Hp2SS. As expected, the genetic polymorphism is reduced in the isolated community. The anthropological significance of these genetic data is discussed.

Treponemal serology and blood groups on Bali island, Indonesia.

As part of a multidisciplinary study of the population of Bali, Indonesia, 2452 blood samples from people of both sexes were tested for treponemal infection and blood groups. Analysis of blood groups of the 81 patients reactive to the Treponema pallidum immobilisation (TPI) test, who were considered to have latent or inactive yaws, compared with a control group of 552 healthy Balinese, showed that the ratio of MM to MN and NN phenotypes was 2.25 times higher in the patients than in the controls (chi 2(1) = 10.2, p less than 0.005). A speculative hypothesis is that yews infection gives people with the MM phenotype a lower selective fitness. This hypothesis could explain the low prevalence of the M gene in the Australo-Melanesian populations.

Serologic markers of hepatitis A and B in the population of Bali, Indonesia.

A total of 343 sera from Balinese subjects in different age groups and geographic locations were tested by radioimmunoassay (RIA) for serum antibodies to hepatitis B surface antigen (anti-HBs) and hepatitis B core antigen (anti-HBc); most sera were also tested for hepatitis B surface antigen (HBsAg), and for antibody to hepatitis A virus (anti-HAV). One hundred percent of the adult population was found to have anti-HAV, with antibody acquisition beginning in early childhood and reaching a level of 95% by the age of 10 years. Antibodies to hepatitis B virus were also frequent in young children, rapidly peaking to near 80% in older children and adolescents, then declining to a plateau that fluctuated between 40% and 60% throughout adult life. Overall, anti-HBc (49%) was detected slightly more often than anti-HBs (45%), but the relative frequencies of the 2 antibodies varied considerably from group to group. Despite these high antibody prevalences, HBsAg was detected in only 1.5% of the general population, and in no woman of child-bearing age. In utero infection is thus far less likely to account for the early acquisition of antibody to hepatitis B virus than inapparent percutaneous transmission occurring under conditions of close personal contact.

Treponemal serology on Bali Island, Indonesia.

As part of a multidisciplinary study of the population of Bali, Indonesia, treponemal serology was carried out on 2452 serum samples from subjects of both sexes. Sera reactive to the Treponema pallidum immobilisation test (TPI) were found in 81 (3.3%) subjects with a male prevalence of 4% and a female prevalence of 2%. All the reactive sera were from villagers. Of 1118 students sampled in various towns, none had reactive TPI tests. The prevalence of reactive sera varied greatly from one village to another; up to 50% of the sera examined were reactive. Geographical and socioeconomic analyses of the data show a strict correlation between poor socioeconomic status and high reactivity rates to the TPI test. Fifty-seven per cent of all the reactive sera originated from subjects living in two districts where yaws had recently been reported. Only three of the 1406 subjects, aged 15-29 years, had reactive sera. The reactivity rate steadily increased in the age groups 30-44, 45-59, and 60 years and over. Biological false-positive reactions occurred in 3.8% of the sera tested.

HLA antigens in Bali (Indonesia) with a special reference to an isolated community.

One hundred eighty-two Balinese were typed for HLA-A and -B locus antigens. From these, 103 were also typed for HLA-C, 51 for HLA-DR, 172 for Bf and 173 for GLO. These results and the significant phenotypic associations are situated with respect to other South-East Asian populations. In addition to this first study, 175 individuals from an isolated Balinese village typed for HLA-A, -B, -DR, Bf and GLO are presented. The effect of isolation on haplotype (HLA-A/-B/Bf/-DR) variability is discussed.

Genetic survey of an isolated community in Bali, Indonesia. II. Haemoglobin types and red cell isozymes.

316 adults and children from an isolated community of Bali, Indonesia, have been tested for 18 red cell enzyme systems controlled by 24 loci, and haemoglobin. 13 loci were invariant. The other 11 loci showed variations similar to those found previously in Southeast Asian populations. Of special interest is the occurrence of lactate dehydrogenase Calcutta-1 variants, indicating Indian gene admixture, and PGM92, indicating a Melanesian genetic component. A few individuals were CA1 1-3Bali and this is possibly the same as other CA1 1-3 types found in the Philippines and Guam. Nearly 10% were glucose-6-phosphate dehydrogenase (G6PD) deficient and 2% carried Hb E. A fast electrophoretic variant of G6PD was detected in 5 persons. Two sub-groups of the population were studied. Gene frequencies in the Isolate supported the view that inbreeding and genetic drift have made this sub-group genetically distinct from the non-inbred part of the population.

Genetic survey of an isolated community in Bali, Indonesia. I. Blood groups, serum proteins and hepatitis B serology.

320 adults and children of an isolated community of Bali, Indonesia, have been tested for blood groups ABO, Rh, MNS, P, Lewis, Duffy, Kell, for haptoglobin and transferrin and for hepatitis B surface antigen and antibodies. Phenotype distribution and gene frequencies are given for the total population tested and for two subgroups representative of the inbred population of the isolate and of the non-inbred part of the population. Significant differences between the two subgroups show a clear genetic drift in the inbred population. The study brings biological support to the ethnological hypothesis of population migrations in this area. Tests for hepatitis B surface antigen reveal a lower prevalence of the disease than in most other south-east Asian populations.