Biochemical polymorphic systems in the migrant population of northeastern USSR. VI. Genetic structure of patients in separate nosological groups

Genotype frequency distribution for a number of polymorphic loci in patients differs significantly in different nosologic groups, in relation to each other and to a sample of healthy individuals. Genetic structure specificity of each nosologic group and different trends of genetic frequency variations, in relation to the sample of healthy individuals, leads to considerable decrease in genetic differences between the united group of pathology and healthy individuals' sample. Spatial differentiation of genetic structure of separate nosologic groups and healthy individuals' sample also confirms genetic isolation of each of these groups and, at the same time, reveals clearly nonspecific biological resistance of human organism.     

Gene pool and gene geography of the USSR population]

Gene pool and gene geography are discussed from the point of view of their conceptual history beginning from the original concept of A.S. Serebrovski? (1928). Difference between the present-day gene geography and gene geography of gene pool is accentuated: the former only represents a portion of the latter. Historical and territorial integrity of the USSR population gene pool, in conjunction with its huge diversity, is the main problem being analysed by various means of computerized genetic cartography. Coupled with the gene frequency mapping, following methods were also used: mapping of average heterozygosity, of interpopulation differentiation, of principal component scores and mapping of geographical trend for each mapped genetic parameter. The work is based on 100 allelic genes and haplotypes from 30 independent loci studied on the average in 225 local populations. Statistical analysis of gene geographical maps is based on 3975 nodes of regular cartographic net for the USSR territory. The wind rose of systematic changes in the USSR gene pool has three main geographic orientations: W-E, SW-NE and S-N. At the same time, there are only two main systematic forces of gene pool evolution: the force of social history with predominant W-E orientation and the force of natural history with predominant S-N orientation of their actions. The heterozygosity level of gene pool declines strictly in accordance with the resultant in the SW-NE direction.     

Biochemical polymorphic systems in the immigrant population of northeastern USSR. V. Dynamics of genetic structure in individuals with different pathological processes depending upon the duration of living under extreme conditions

It is shown that specificity of the genetic structure in individuals with different pathologic processes is interrelated to the duration of life under the extreme conditions, and its "dynamics" is contrary to that of healthy inhabitants of the region. The extent of genetic differences between groups in man and woman samples, and also between men and women in groups does not depend on the extent of differences between these groups in frequency of nosologic forms. The latter indicate that the genotype shows nonspecific disease resistance on the whole, but not to the given pathologic process. The prevalence of the average real heterozygosity over the theoretical one in sick men and the reverse effect in healthy men points to formation of new heterozygosity optimum in the extreme conditions, leading to decline in the population genetic diversity, which rather corresponds to the specific ecology. The comparison of groups of sick and healthy individuals of different life duration in the North shows that the specific weight of genotype nonspecific resistance to diseases depends mostly on the duration of life of individuals under extreme conditions, this dependence being not linear.     

Genetic analysis of a population with abnormalities of gene frequencies]

Nineteen out of the 53 blood donors of french village with 241 inhabitants (Cezay Loire) are Rh negative (D--). This discrepancy in the distribution is analysed. 1.--The study of the genetic erythrocyte markers (ABO and Rh system for 158 inhabitants, Kell, Rautenberg, Duffy, Kidd, MNSs, P1 Lutheran, PGM1, PGM2, 6 PGD, AK, ADA, Acid phosphatase systems for 104 inhabitants) show significant abnormal gene frequencies (No. 10%) compared with a control population from Saint-Etienne, for A1, Ms, r, P1 alleles; conversely rare alleles do not seem to exist. HLA system was not tested. 2.--The genetic study led to: a) a demographic study which implied 7840 registrar's certificates and the building up of 1364 families to which the 5096 subjects belonged identified and having lived in Cezay since 1607 (this date corresponds to the earliest registrar's certificate). b) it also led to the analysis of the origin and evolution of the genetic inheritance throughout the 13 generations of known inhabitants. The calculation of the chances of each generation having passed on its genetic material to following generations shows that: Cezay has an integrated population; 30% of the genes are renewed for each generation the average value of each founder can vary according to the various generations but there seems to exist a "founder effect" of the Rh--(D--) having been and lived in the village before 1860. Although they represent 68% of the total population, the tested samples can be contested for certain systems, in its constitution (formation, choice) which prevents from ascertaining the foundation effect observed. The authors underligne the contribution of immunogenetics to the genetics of populations, and show the incidence of the choice of samples in the method used.     

Temporal changes of gene frequencies in Cepaea hortensis

There have been few studies analysing long-term changes of gene frequencies in natural populations. This work is the first report of such changes in the land snail Cepaea hortensis (Mull).
Collections of C. hortensis were made at Silbury Hill, Wiltshire in 1957, 1963 and 1978. The banded phenotype significantly declined in frequency between 1963 and 1978. It is argued that the decline, which was statistically homogeneous at 15 separate sites within the area, was a consequence of natural selection. The average selection coefficient against the banded homozygote is estimated to have been greater than 1096.     

A study of nine polymorphic systems in the population of the Po Delta

The present work reports a study of nine genetic polymorphic systems in the area of the Po Delta where malaria was endemic since the XIV century. Our data confirm some characteristics of this population already reported by other authors such as the high prevalence of thalassemia, the low prevalence of the rh (d) gene and the presence of G-6-PD deficiency. Among the other systems studied, i.e., AP, PGM₁ ADA and AK, only AP frequencies of Po Delta population are significantly different from those of other continental Italian populations, the P^C allele showing the lowest frequency so far observed.     

Gaucher disease: gene frequencies in the Ashkenazi Jewish population.

DNA from over 2,000 Ashkenazi Jewish subjects has been examined for the four most common Jewish Gaucher disease mutations, which collectively account for about 96% of the disease-producing alleles in Jewish patients. This population survey has made possible the estimation of gene frequencies for these alleles. Eighty-seven of 1,528 individuals were heterozygous for the 1226G (N370S) mutation, and four presumably well persons were homozygous for this mutation. The gene frequency for the 1226G allele was calculated to be .0311, and when these data were pooled with those obtained previously from another 593 Jewish subjects, a gene frequency of .032 with a standard error of .004 was found. Among 2,305 normal subjects, 10 were found to be heterozygous for the 84GG allele, giving a gene frequency of .00217 with a standard error of .00096. No examples of the IVS2(+1) mutation were found among 1,256 samples screened, and no 1448C (L444P) mutations were found among 1,528 samples examined. Examination of the distribution of Gaucher disease gene frequencies in the general population shows that the ratio of 1226G mutations to 84GG mutations is higher than that in the patient population. This is presumed to be due to the fact that homozygotes for the 1226G mutation often have late-onset disease or no significant clinical manifestations at all. To bring the gene frequency in the patient population into conformity with the gene frequency in the general population, nearly two-thirds of persons with a Gaucher disease genotype would be missing from the patient population, presumably because their clinical manifestations were very mild.     

The use of the expectation-maximization (EM) algorithm for maximum likelihood estimation of gametic frequencies of multilocus polymorphic codominant systems based on sampled population data

Estimation of gametic frequencies in multilocus polymorphic systems based on the numerical distribution of multilocus genotypes in a population sample ("analysis without pedigrees") is difficult because some gametes are not recognized in the data obtained. Even in the case of codominant systems, where all alleles can be recognized by genotypes, so that direct estimation of the frequencies of genes (alleles) is possible ("complete data"), estimation of the frequencies of multilocus gametes based on the data on multilocus genotypes is sometimes impossible, whether population data or even family data are used for studying genotypic segregation or analysis of linkage ("incomplete data"). Such "incomplete data" are analyzed based on the corresponding genetic models using the expectation-maximization (EM) algorithm. In this study, the EM algorithm based on the random-marriage model for a nonsubdivided population was used to estimate gametic frequencies. The EM algorithm used in the study does not set any limitations on the number of loci and the number of alleles of each locus. Locus and alleles are identified by numeration making possible to arrange loops. In each combination of alleles for a given combination of m out of L loci (L is the total number of loci studied), all alleles are assigned value 1, and the remaining alleles are assigned value 0. The sum of zeros and unities for each gamete is its gametic value (h), and the sum of the gametic values of the gametes that form a given genotype is the genotypic value (g) of this genotype. Then, gametes with the same h are united into a single class, which reduces the number of the estimated parameters. In a general case of m loci, this procedure yields m + 1 classes of gametes and 2m + 1 classes of genotypes with genotypic values g = 0, 1, 2, ..., 2m. The unknown frequencies of the m + 1 classes of gametes can be represented as functions of the gametic frequencies whose maximum likelihood estimations (MLEs) have been obtained in all previous EM procedures and the only unknown frequency (Pm(m)) that is to be estimated in the given EM procedure. At the expectation step, the expected frequencies (Fm(g) of the genotypes with genotypic values g are expressed in terms of the products of the frequencies of m + 1 classes of gametes. The data on genotypes are the numbers (ng) of individuals with genotypic values g = 0, 1, 2, 3, ..., 2m. The maximization step is the maximization of the logarithm of the likelihood function (LLF) for ng values. Thus, the EM algorithm is reduced, in each case, to solution of only one equation with one unknown parameter with the use of the ng values, i.e., the numbers of individuals after the corresponding regrouping of the data on the individuals' genotypes. Treatment of the data obtained by Kurbatova on the MNSs and Rhesus systems with alleles C, Cw, c, D, d, E, e with the use of Weir's EM algorithm and the EM algorithm suggested in this study yielded similar results. However, the MLEs of the parameters obtained with the use of either algorithm often converged to a wrong solution: the sum of the frequencies of all gametes (4 and 12 gametes for MNSs and Rhesus, respectively) was not equal to 1.0 even if the global maximum of LLF was reached for each of them (as it was for MNSs with the use of Weir's EM algorithm), with each parameter falling within admissible limits (e.g., [0, min(PN,Ps)] for PNs). The chi 2 function is suggested to be used as a goodness-of-fit function for the distribution of genotypes in a sample in order to select acceptable solutions. However, the minimum of this function only guarantee the acceptability of solutions if all limitations on the parameters are met: the sum of estimations of gametic frequencies is 1.0, each frequency falls within the admissible limits, and the "gametic algebra" is complied with (none of the frequencies is negative).     

Allele frequencies and linkage disequilibrium of polymorphic DNA markers of the Huntington disease region in the German population

Allele frequencies of 14 different restriction fragment length polymorphisms from 12 DNA markers within the Huntington disease (HD) region were evaluated in the German population. No significant differences from published data of allele frequencies from chromosomes of Caucasian ancestry were found. The analysis of eight DNA polymorphisms in 87 HD families of German origin revealed significant non-random association with the HD locus and the D4S95 locus (p674/AccI/MboI), a result that is consistent with all other published studies. These results are confirmed by the fact that the HD gene maps to this region.     

Polymorphic biochemical systems in a population of newly arrived inhabitants of the northeastern USSR. IV. The characteristics of the genetic structure of persons with chronic pathological processes

Analysis of properties of the genetic structure in 2847 individuals with different chronic diseases (1261 men and 1586 women) for 14 polymorphic loci (AcP, PGM1, PGD, GPT, GLO-I, EsD, AK, Pp, E2, Hp, Gc, Tf, AB0 and Rh) is presented. Discrepancy between the observed and expected phenotype frequencies for PGM1, GLO-I, EsD and AB0 loci is observed in a sample of patients Deviation from the expected frequencies is unequal for the representatives of different sex. Male and female portions of the sample differ significantly from each other for AcP, GPT, GLO-I, AK, EsD, Tf and AB0 loci, i. e. for 7 from 14 systems analysed. Highly significant differences between healthy and sick individuals have been detected: in general samples for 8 loci (AcP, PGM1, GPT, GLO-I, AK, Pp, Hp, AB0); in men for 8 loci (AcP, GPT, AK, PGD, Pp, Tf, AB0); in women for 5 loci (PGD, Pp, Gc, Tf, AB0). The difference between sick and healthy individuals of different sex is not only of qualitative but also of quantitative expression. The difference between sick and healthy men is much stronger, as compared to that between women. A decline in the average heterozygosity is noted in sick individuals. From the results obtained it is possible to conclude that the group of different pathologic conditions for the complex of genetic parameters differs significantly from that of healthy individuals. This may be a reflection of adaptation and disadaptation processes under the extreme environmental conditions.     

MspI polymorphic site in intron 22 of the factor VIII gene in the Japanese population

Summary A novel MspI DNA polymorphic site has been found in intron 22 of the human factor VIII gene. This site is informative almost exclusively in the Japanese population (heterozygosity 0.45) and will be of considerable importance in carrier detection and prenatal diagnosis of hemophilia A in this population.     

Association of ADAM33 gene polymorphisms with psoriasis in a northeastern Chinese population

Psoriasis (PS) is a common hyperproliferative and chronic inflammatory disease of the skin. It is influenced by both genetic and environmental factors. The ADAM33 (a disintegrin and metalloproteinase 33) gene located on chromosome 20p13, has recently been identified as an asthma-susceptibility gene by positional cloning. Recently, ADAM33 has been suspected to be associated with PS. To study the association between ADAM33 and PS in the northeastern Chinese population. A total of 240 PS patients and a control group of 237 healthy volunteers were recruited for this study. Five polymorphic loci (V4, T+1, T2, T1, S2) of ADAM33 were selected for genotyping. Genotypes were determined by using the polymerase chain reaction–restriction fragment length polymorphism method. We observed the frequency of the rs2787094 C allele was significantly higher in cases than in controls (50 vs. 33 %, P < 0.0001).Similarly, the rs528557 C allele exhibited a significantly increased frequency in PS patients compared with healthy controls (35 vs. 21 %, P < 0.0001). We also found that the frequencies of H3 (CGGAC), H6 (CGGGG) haplotypes were significantly higher in the case group than in the control group (P = 0.006, 0.028, respectively). In contrast, the haplotype H9 (GAAAG) was more common in the control group than in the case group (P = 0.018). Our data suggest that the ADAM33 polymorphisms may be associated with PS in the northeastern Chinese population.     

Gene frequencies and heterozygosity of the population of Donetsk Province, Ukraine by the alleles of the ABO and Rhesus systems]

Frequency and heterozygosity indices of AB0 and Rh gene systems in the population of Donetsk Province were calculated. Uneven distribution of the genes was found and heterozygosity indices of the population were 0.554-0.573 for AB0 and 0.410-0.499 for Rh. Heterozygosity in this population was higher than average heterozygosity in total population of Ukraine as a result of intensive migrations and prevalence of heterolocal marriages over homolocal ones.     

Eight polymorphic blood protein systems in Arab horses from Turkey]

Analysis of the blood protein system was used to study the genetic composition of Arabian horses. Biochemical markers of eight polymorphic loci (Tf, Al, Es, AlB, Gc, Hb, PGD, and PGM) were electrophoretically identified in blood samples. A total of 43 phenotypes were identified for these polymorphic systems. The Tf, Hb, and Es loci appeared to be more polymorphic than the other loci studied. Statistically significant differences between the observed and expected genotypic frequencies were found for the PGD and PGM loci (P < 0.05 and P < 0.01, respectively). Individual allele frequencies, observed and expected phenotype frequencies, and the average heterozygosity were estimated for each polymorphic locus.     

Plasma transferrin phenotype and gene frequencies in the population of Rome (Italy)

Summary Frequencies of transferrin phenotypes and genes were determined in a sample of 319 randomly selected subjects from the population of Rome. Disc electrophoresis on acrylamide gel columns was adopted for the phenotype identification. A statistical analysis on these and all the data so far collected in other areas of the world would suggest that a high degree of homogeneity is present among white populations, while a certain degree of heterogeneity exists among coloured populations.     

Analysis of the formation of systems of conditioned reflexes to time in rabbits]

Experiments on rabbits carried out by the food-procuring conditioned reflex method have shown that conditioned reflex systems to "pure" time can be elaborated, provided that conditioned stimulus is presented at regular, though different time intervals, following one another in a fixed sequence. The complexity of elaborating such systems to time is determined by the number of signal time intervals in the system, their different length, and their sequence. The formation of conditioned reflex systems to time is characterized by definite stages.     

Perturbation of gene frequencies in a natural population of Drosophila melanogaster: evidence for selection at the Adh locus

The cellar population of Drosophila melanogaster at the Chateau Tahbilk Winery (Victoria, Australia) was perturbed for alcohol dehydrogenase (Adh) gene frequencies. Phenol oxidase (Phox) frequencies were also perturbed and monitored as a control. Subsequent gene frequency changes, together with information on population structure, indicated that selection acted on the chromosome regions of both loci. Adh gene frequencies returned to preperturbation levels in a predictable manner. A model in which the relative fitness of Adh phenotypes was determined by temperature-dependent specific activities of enzymes of Adh genotypes adequately accounts for the rate of gene frequency change at this locus. Thus temperature behaves as a selective agent in modulating Adh gene frequencies in this cellar environment.