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At least 19 recordsLinked to original sources

[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. Serebrovskiĭ (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.

Alleles

[Ethnogenetics: adaptive structure of the gene pool of the mankind from the data on human polymorphic genetic markers].

The mean FST value as a characteristic of gene frequency changes in a random sample of polymorphic genes from population gene pool provides the best indirect estimation of selectively neutral level of genetic variability. The set of test criteria, including chi 2, F and t, can be used in order to compare F1 with F and subdivide gene sample into three subgroups, or classes of genes which are differing from each other by the degree of variation of allelic frequencies. These three classes comprise the adaptive structure of gene pool and consist of the genes which are, respectively, under stabilizing and differentiating selection pressures or neutral ones. Adaptive structures of gene pools of aboriginal human populations at the main 9 geographical regions of the World, taken together, reveal statistically significantly correlation with adaptive structure of the total gene pool of the Mankind. But the correlation is rather small and therefore, the adaptive structure of human gene pool reveals between adaptive structures, the highest is for the USSR and the lowest are for the East-Asiatic and Australian regions. The proportion of neutral to non-neutral genes is about 50% in the average, with the range of variation 40-60% in different regions. But none of the polymorphic genes so far studied reveals constant neutrality in all regional conditions of environment and at different times of evolution history of human gene pool. Its adaptive structure underwent essential transformation from the Palaeolithic till the Postpalaeolithic times, but nevertheless, among the main features of contemporary adaptive structure of human gene pool, those predominate which are of the Palaeolithic origin.

Alleles

Allelic and genotypic composition of ancestral Spanish and colonial Californian gene pools of Avena barbata: evolutionary implications.

Spanish explorers and colonists inadvertently started a massive experiment in evolutionary genetics when they accidentally introduced Avena barbata to California from Spain during the seventeenth and eighteenth centuries. Assays of the Spanish and Californian gene pools of this species for 15 loci show that the present day Spanish gene pool, particularly that of Southwestern Spain, is identical or virtually identical to that of California for five loci and closely similar for nine loci. Despite their similar allelic and single-locus genotypic compositions, the present-day Spanish and Californian gene pools are differently structured on a multilocus genetic basis. Evolutionary implications of these results are discussed.

Alleles

[Ethnic genetics: ethnogeographic diversity of the gene pool of human populations around the world].

The study was undertaken to estimate a degree of genetic differentiation in human all-world population at the ethnic level of its structure. The genetic information for this work came from well-known A. Mourant's et al. world-wide survey on human genetic polymorphisms and from regional survey on the same polymorphisms of the USSR peoples. The data were grouped into 9 regional populations studied for 49 alleles and haplotypes belonging to 20 polymorphic loci. Average genetic distances from the all-world human gene pool to each of regional one, and from these to gene pools of ethnic groups within regions were estimated and compared. An unexpected result of this within-between-region comparative analysis is the shortest genetic distance between gene pools of the USSR peoples as a whole on the one hand, and all-world peoples on the other. At the same time, a considerable part of the total human genetic polymorphism is persisted in the USSR region.

Americas

[Preservation of the plant and animal gene pools in Siberia].

The results of the work on preservation of the gene pools performed at the two experimental bases of the Institute of Cytology and Genetics of the Siberian Division of Academy of Sciences of the USSR are summarized. The collections obtained are represented by a number of aboriginal animal breeds (cattle, sheep, foxes, etc.) and plant variables (300 specimens belong to 113 species of 25 families.

Animals

The Great Island subgroup of tick-borne orbiviruses represents a single gene pool.

The geographical distribution of members of the Great Island (GI) subgroup in the Kemerovo serogroup of orbiviruses extends from the Arctic to the Sub-antarctic. To examine the gene pool size of this group, five topotypes whose origins ranged from Iceland in the northern hemisphere to Macquarie Island in the Southern Ocean were tested for their ability to reassort in vitro. All the isolates were distinguishable by plaque reduction neutralization tests, and their genome profile in polyacrylamide gels. They showed high frequency reassortment following dual infection of cell cultures with temperature-sensitive (ts) mutants and/or wild-type virus. Analysis of the dsRNA profile of the reassortants by PAGE confirmed the observation from reassortment assays that the Great Island subgroup constitutes a single gene pool. A seventh reassortment group was identified, distinct from the six groups previously described. The ts lesions for reassortment groups I, V and VII were considered to be in genome segments 9, 3 and 2, respectively. Segment 6 of GI virus (in contrast to segment 5 of Broadhaven and Wexford viruses) was shown to be the major genetic determinant of serotype specificity.

Animals

Genomic response to sex-separated gene pools.

Males and females experience differences in the strength and direction of selection but discerning the type of genes that are targets of sex differences in selection is complicated by their shared genome. We used experimental evolution in Drosophila melanogaster to partially separate the gene pools of males and females for 130 generations. In six replicate populations, we forced one pool of genetically variable Chromosome 2s to experience patrilinear inheritance (segregating like a Y-chromosome) and male-limited selection. The alternative pool segregated like an X-chromosome and experienced female-biased selection. This allowed alleles which are differentially selected for between the sexes to diverge between these pools, enabling us to gain insight into the type of genes subject to such selection. We find that genes which diverge between these pools have an elevated intersexual genetic correlation(rMF) for expression on average, consistent with the idea that high genetic correlations may hinder sex-specific adaptation under normal inheritance. Diverged genes were also enriched for moderately male-biased genes whereas female-biased genes were underrepresented. At the SNP level, we find an overrepresentation of diverged SNPs involved in splicing or occurring in the 5'UTR and an underrepresentation of missense or synonymous SNPs, suggesting sex differences in selection for isoform usage.

intersexual genetic correlation

How voluntary prenatal diagnosis and selective abortion increase the abnormal human gene pool.

It is often assumed that prenatal diagnosis followed by the selective abortion of "defective" fetuses has a positive eugenic effect. Although mandatory selective abortion of "defective" fetuses and, more important, carriers would tend to reduce the number of deleterious genes in the gene pool, the present program of voluntary prenatal diagnosis and selective abortion actually increases the number of deleterious genes. This raises the issue of freedom of choice regarding selective abortion and societal pressure on parents to undergo prenatal testing and to abort their fetus should it have a genetic disorder or be a carrier of one.

Abortion, Therapeutic

Autoantibodies and autoantigens: a conserved system that may shape a primary immunoglobulin gene pool.

Formation of certain autoantibodies is associated with a variety of autoimmune diseases, but the production of small amounts of autoantibodies also occurs in the normal immune system. Germline-encoded IgM antibodies that are autoreactive and bind to diverse antigen structures with low affinity are prominent in the primary antibody repertoire. Many IgG disease-related autoantibodies differ in structure and binding properties from these normally occurring IgM autoantibodies. The two sets may arise independently, but some properties, such as shared idiotypes, link some members of the two populations. Many autoantigen targets of both sets of autoantibodies are structurally conserved among species, as are certain features of the autoantibodies themselves. These elements, interacting before exposure of the system to foreign antigens, may constitute a conserved system that contributes to shaping and maintaining a primary immunoglobulin gene pool.

Autoantibodies

[Koryaks of Kamchatka. The genetic characteristics and formation of a gene pool].

Investigation of korak population of Kamchatka is carried out for 10 non-linked blood groups loci, serum proteins, PTC taste and ABH antigens secretion. The korak population enters in the system of Middle Asian mongoloids for the genetical characteristics studied. Koraks occupy an intermediate position between Siberian and Far East populations in their genetic pecularities, revealing the most close genetical similarity with Siberian population. The main contribution in the genofond of ancient korak athnic community is carried by neolytic inhabitants of Siberia.

Asia, Southeastern