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PubMed2000

[Formation of a gene pool of miniature Siberian swine "Minisibs" and their use in medico-genetic research].

The results of 35-year breeding of a new variety of laboratory animals for biological and medical studies, termed Minisibs (miniature Siberian swine), are summarized. Minisibs were obtained via hybridization between Swedish Landrace pigs, who have an epistatic white coat color, and black Vietnamese masked pigs of breed I, who have genes of dwarfism. Some genes of wild boars Sus scrofa scrofa and S. s. nigripes from Central Europe and Central Asia, respectively, were introduced to the Minisibs gene pool in order to strengthen the constitution, increase the general resistance, and improve the functions of the cardiac muscle and valves. The pigs were selected for a decrease in body weight and an increase in litter size over 15 generations. Immunogenetic and chromosomal polymorphisms were constantly monitored by Robertsonian translocations Rb 15/17 and Rb 16/17 introduced from boars. Long-term breeding produced a population of laboratory pigs with an average adult weight of approximately 60 kg, a litter size of seven to eight piglets, and quiet behavior. Most of animals used in selection were white, which is essential for radiobiological experiments and studies on skin histocompatibility. Introduction of chromosomal polymorphism to the minipig gene pool and long-term immunogenetic and cytogenetic monitoring made it possible to perform subchromosomal mapping of the loci of some blood-group systems associated with the loci controlling coat color, litter size, stress resistance and meat quality (halothane sensitivity), and histocompatibility. Minisibs have been successfully used in numerous biomedical studies and in therapeutic and surgical cardiology (for production of diagnostic sera controlling lipid metabolism and of biological prostheses of cardiac valves). The anatomical and physiological similarity of Minisibs to humans indicate that these animals may serve as donors of xenografts for orthotopic heart transplants to humans.

Animals↗
PubMed1988

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↗
PubMed1998

Clines of nuclear DNA markers suggest a largely neolithic ancestry of the European gene pool.

Comparisons between archaeological findings and allele frequencies at protein loci suggest that most genes of current Europeans descend from populations that have been expanding in Europe in the last 10, 000 years, in the Neolithic period. Recent mitochondrial data have been interpreted as indicating a much older, Paleolithic ancestry. In a spatial autocorrelation study at seven hypervariable loci in Europe (four microsatellites, two larger, tandem-repeat loci, and a sequence polymorphism) broad clinal patterns of DNA variation were recognized. The observed clines closely match those described at the protein level, in agreement with a possible Near Eastern origin for the ancestral population. Separation times between populations were estimated on the basis of a stepwise mutation model. Even assuming low mutation rates and long generation times, we found no evidence for population splits older than 10,000 years, with the predictable exception of Saami (Lapps). The simplest interpretation of these results is that the current nuclear gene pool largely reflects the westward and northward expansion of a Neolithic group. This conclusion is now supported by purely genetic evidence on the levels and patterns of microsatellite diversity, rather than by correlations of biological and nonbiological data. We argue that many mitochondrial lineages whose origin has been traced back to the Paleolithic period probably reached Europe at a later time.

Cell Nucleus↗
PubMed1996

[The gene pool of native inhabitants of the Samburg tundra].

This study continues a series of investigations of the gene pool of native Siberian ethnic groups. In a population of Tundra Nentsi (Northern Samoyeds) and a group of Komi-Zyryans (Finno-Ugrian) (Samburg settlement, Tyumenskaya oblast, Yamalo-Nenetskii Autonomous okrug), gene markers of the following genetic systems were studied: blood groups (ABO, MNSs, Rhesus, Kell, Duffy, and P), erythrocyte acid phosphatase (AcP), phosphoglucomutase 1 (PGM 1), haptoglobin (Hp), and transferrin (Tf). The population of Samburg Tundra Nentsi was shown to have a close genetic relationship with the "core" of the Forest Nentsi population. In Northern Samoyeds, three carriers of the rare allele K (blood group Kell) were found for the first time. It is suggested that this allele was transferred into the population of Tundra Nentsi from Komi. Samburg Tundra Nentsi are found to have the maximum frequency of the allele PGM 1 (Posphoglucomutase 1) among aboriginal populations of northern Asia. Analysis of original data and the literature revealed a significant genetic distance between the Komi and Northern Samoyed populations. It was shown that Samburg Komi occupy an intermediate position between the clusters of Nenets populations and Finno-Ugrians (Komi) living in Komi Republic.

Alleles↗
PubMed2001

[Structural organization of the gene pool of the Ukrainian steppe white pig breed from immunogenetic markers].

The study of structural organization of gene pool was conducted for eight blood-group genetic systems (transferrin, haptoglobin, and amilase) in three stock herds of pigs of the Ukrainskaya Stepnaya Belaya breed that were bred under the conditions of southern Ukraine. Typical gene combinations (complex genotypes) of this breed were detected, and the main breed-specific parameters of distribution of genetic markers were described.

Amylases↗
PubMed2007

Molecular genetic studies of natives on Easter Island: evidence of an early European and Amerindian contribution to the Polynesian gene pool.

Most archaeological and linguistic evidence suggest a Polynesian origin of the population of Easter Island (Rapanui), and this view has been supported by the identification of Polynesian mitochondrial DNA (mtDNA) polymorphisms in prehistoric skeletal remains. However, some evidence of an early South American contact also exists (the sweet potato, bottle gourd etc.), but genetic studies have so far failed to show an early Amerindian contribution to the gene pool on Easter Island. To address this issue, we analyzed mtDNA and Y chromosome markers and performed high-resolution human leukocyte antigen (HLA) genotyping of DNA harvested from previously collected sera of 48 reputedly nonadmixed native Easter Islanders. All individuals carried mtDNA types and HLA alleles previously found in Polynesia, and most men carried Y chromosome markers of Polynesian origin, providing further evidence of a Polynesian origin of the population of Easter Island. A few individuals carried HLA alleles and/or Y chromosome markers of European origin. More interestingly, some individuals carried the HLA alleles A*0212 and B*3905, which are of typical Amerindian origin. The genealogy of some of the individuals carrying these non-Polynesian HLA alleles and their haplotypic backgrounds suggest an introduction into Easter Island in the early 1800s, or earlier. Thus, there may have been an early European and Amerindian contribution to the Polynesian gene pool of Easter Island.

American Indian or Alaska Native↗
PubMed2005

[The development of the gene pool in the microevolution of Sus scrofa and the role of heterozygosity in the breed-forming process].

The gene pool formation of the modem domestic breeds of pig Sus scrofa domestica and their genesis based on hybridization of wild ancestral forms of the European and Asian origin were studied using molecular immunogenetic methods. Males of the European and Central Asian S. scrofa subspecies (S. s. scrofa and S. s. nigripes were hybridized with domestic pigs of the Swedish Landrace and Vietnamese Black Masked breeds. In addition, we examined the genotypic structure of 65 wild, aboriginal, and local populations as well as cultured breeds, including the stock breeds with different levels of selection. Frequencies of alleles and suballelles of the chromosome 4 locus controlling antigens of the L blood group system were analyzed. The origin of marker suballeles of the European and Asian origin was estimated in the most widespread world pig breeds. Unexpectedly, a strikingly high frequency of the Asian elements was found in the most productive European and American breeds, as well as in the best breeds of Russia and other CIS countries. Only one form of heterozygosity (bcgi/bdfi) was found in a population of wild European ancestors, whereas domestic pig breeds displayed heterozygosity for far more numerous suballeles of the locus studied. Animals heterozygous for alleles of the European and Asian origin showed higher adaptivity and fertility.

Animals↗
PubMed2026

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↗
PubMed1999

[Characteristics of the gene pool of the Gagauz population of Moldova].

Population genetic data on Gagauzes from Moldova are reported for the first time. Blood groups AB0 and Rh and biochemical markers of genes HP, TF, GC, and PGM1 were determined in 190 Gagauzes. The following allelic frequencies were determined: AB0*0, 0.5241; AB0*A, 0.3279; RH*d, 0.4571; HP*1, 0.3544; TF*C1, 0.7472; TF*C2, 0.1770; TFC3, 0.0730; TF*B, 0.0028; GC*1F, 0.1025; GC*1S, 0.5932; GC*2, 0.3043; PGM1*1+, 0.5286; PGM*1-, 0.1000; PGM1*2+, 0.2607; and PGM1*2-, 0.1107. The data obtained indicate that the gene pool of Gagauzes is similar to those of neighboring southeastern European populations.

ABO Blood-Group System↗
PubMed1998

Male fitness increases when females are eliminated from gene pool: implications for the Y chromosome.

Because the two sexes share a common gene pool while performing many different biological functions, mutations benefiting one sex may not accumulate due to counter selection in the other sex. In these experiments 99% of a haploid genome of Drosophila melanogaster was constrained to segregate like a male-limited Y chromosome for 41 generations, thereby eliminating potential counter selection in females. The synthetic Y chromosomes rapidly accumulated genetic variation that increased male fitness and decreased female fitness. The survival and fertility of females declined when they were mated to males expressing the synthetic Y chromosomes. These results suggests that opposing selection between the sexes may substantially interfere with sex-specific adaptation. They also demonstrate how intersexual evolutionary conflict can lead to perpetual degeneration of the Y via genetic hitchhiking of deleterious mutations.

Animals↗
PubMed2000

Sex gene pool evolution and speciation: a new paradigm.

In this paper, we review the literature on the growing body of data demonstrating the rapid evolution of sex and reproduction related (SRR) genes and show how a paradigm shift to the study of SRR genes can provide new approaches to solving some of the old problems in evolutionary biology. The argument is based on (1) the growing scope and importance of sexual selection in evolution, (2) the growing number of case studies showing rapid evolution of sexual traits in a wide variety of taxa, (3) the faster rate of DNA sequence divergence in genes affecting sexual function and fertility, (4) the evidence for the involvement of novel traits/genes in sexual functions, and (5) a proposed sex/non-sex dichotomy of the gene pool affecting viability versus fertility. It is argued that the adoption of the sex/non-sex dichotomy of genes/traits can provide new perspectives on such problems as species concepts, modes (allopatric/sympatric) of speciation, Haldane's rule, reinforcement, and the founder effect. It is proposed that the evolutionary study of genes affecting viability versus fertility is the key to understanding the genetic basis of speciation.

Animals↗
PubMed1990

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↗
PubMed1995

Messages from an isolate: lessons from the Finnish gene pool.

Genetic isolates are the result of some type of bottleneck in the history of a population, revealing the consequences of the founder effect and genetic drift on the population's gene pool. In human populations, isolation is suspected based on an exceptional geographic location or cultural history or on the prevalence of relatively rare genetic diseases. The concept of 'Finnish disease heritage' is well established in the literature, but solid data have only recently emerged regarding the uniformity of disease mutations at the molecular level in this population: for many Finnish diseases for which the molecular defect has been uncovered, over 90% of disease alleles carry the same causative mutation. This suggests dramatic isolation, especially in some subregions of the sparsely populated country. In Finland, this molecular information can be combined with the exceptional genealogical data offered by a well established church record system which dates back to 1640, containing detailed information on births, deaths, marriages and movements of the majority of the population. This provides excellent opportunities for special study designs for the identification not only of rare disease genes but also of major loci which contribute to complex diseases. The utilization of linkage disequilibrium and the search for shared haplotypes can be justified in subpopulations and patient materials from this genetic isolate. This review summarizes the current molecular evidence for genetic isolation as well as the utilization of some special strategies in the disease gene hunt in the Finnish population.

Finland↗
PubMed1999

[Structure and diversity of the mitochondrial gene pool of the aboriginal population of Tuva and Buriatia from restriction polymorphism data].

The populations of Tuvinians (N = 36) and Buryats (N = 105) were characterized by using the data on mitochondrial DNA (mtDNA) polymorphism. The gene pools of both ethnic groups possessed the mtDNA types belonging to the four main haplogroups, A, B, C, and D, found only in the indigenous populations of Asia and America. The total frequencies of the A, B, C, and D haplogroups in Tuvinians and Buryats were 72.3% and 52.4%, respectively. These values, along with the frequency for Altai populations (57.2%), were highest in the Asian populations studied, indicating that the populations Southern and Eastern Siberia can be considered as ancestral relatives to the ethnic groups of the New World. Analysis of the mtDNA region V polymorphism showed the presence of 9-bp deletion and 4-bp insertion in both populations with frequencies respectively of 13.9 and 5.56% in Tuvinians and 4.8 and 1.9% in Buryats. The frequency of the +AvaII/8249 variant was 11.1% in Tuvinians and 3.81% in Buryats. Analysis of the association between the region V deletion-insertion polymorphism and certain restriction haplogroups pointed to repeated and independent emergence of the 4-bp insertion in Siberia.

Base Sequence↗
PubMed1984

Inbreeding and the gene pool.

The trend in the artificial insemination industry in recent years has been to sample larger numbers of sons sired by the most popular bulls. This trend has caused concern in the dairy industry regarding inbreeding and the gene pool. The known detrimental effects of inbreeding on economically important traits are one reason for this concern, and these are reviewed here. Also reviewed and discussed are estimates of inbreeding in dairy cattle populations. These estimates indicate that for the populations studied, inbreeding has increased little if at all during the period of widespread use of artificial insemination. During the 1970's average inbreeding in United States Holsteins and British Friesians was on the order of 3 to 6% relative to their foundations. A recent study of inbreeding in United States Ayrshires suggests little inbreeding in that breed in spite of the relatively small population size. Inbreeding and preservation of genetic variation should be minor concerns in selecting sires.

Animals↗
PubMed2004

Distinction between wild and cultivated enset (Ensete ventricosum) gene pools in Ethiopia using RAPD markers.

In southwest Ethiopia, the cultivation area of Ensete ventricosum (enset) overlaps with the natural distribution area of this species. Analyses of genetic diversity were undertaken using RAPD to provide information for conservation strategies as well as evidence of possible gene flow between the different gene pools, which can be of interest for future improvement of cultivated enset. The extent of RAPD variation in wild enset was investigated in 5 populations in the Bonga area (Kefficho administrative region) and 9 cultivated clones. Comparisons were also made with some Musa samples of potential relevance for crop improvement. Nine oligonucleotide primers amplified 72 polymorphic loci. Population differentiation was estimated with the Shannon index (G'(ST)=0.10), Nei's G(ST) (0.12) and AMOVA (Phi(ST)=0.12), and appears to be relatively low when compared with outbreeding, perennial species in general. Cluster analysis (UPGMA) and principal component analysis (PCA) similarly indicated low population differentiation, and also demonstrated that cultivated clones essentially clustered distinctly from wild enset samples, suggesting that the present-day cultivated enset clones have been introduced to domestication from a limited number of wild progenitors. In addition, subsequent gene flow between wild and cultivated enset may have been prohibited by differences between modes of propagation and harvesting time; cultivated enset is propagated vegetatively through sucker production and the plant is generally harvested before maturity or flower set, thereby hindering pollination by wild enset or vice versa. A significant correlation was not found between genetic and geographical distances. The relatively high total RAPD diversity suggests that wild enset populations in the Bonga area harbour genetic variability which could potentially act as a source for useful or rare genes in the improvement of cultivated enset. As expected, E. ventricosum was clearly differentiated from the analysed Musa samples, that clustered in accordance with the present morphology- and molecular marker-based taxonomy of the genus.

DNA, Plant↗