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PubMed1999

Molecular genetics of the Finnish disease heritage.

Finland, located at the edge of the inhabitable world, is one of the best-studied genetic isolates. The characteristic features of population isolates-founder effect, genetic drift and isolation-have, over the centuries, shaped the gene pool of the Finns. Finnish diseases have been a target of extensive genetic research and the majority of some 35 disease genes enriched in this population have been identified; the molecular and cellular consequences of disease mutations are currently being characterized. Special strategies taking advantage of linkage disequilibrium have been efficiently used in the initial mapping and restriction of Finnish disease loci and this has stimulated development of novel statistical approaches in the disease gene hunt. Identification of mutated genes has provided tools for detailed analyses of molecular pathogenesis in Finnish diseases, many of which reveal a distinct tissue specificity of clinical phenotype. Often these studies have not only clarified the molecular detail of Finnish diseases, but also provided novel information on biological processes and metabolic pathways essential for normal development and function of human cells and tissues.

Chromosome Mapping↗
PubMed2001

[Analysis of the genetic structure of the breeding nucleus of the Russian population of purebred Thoroughbred horses at the Extension locus using molecular DNA typing].

Results of the first in Russia survey of the gene pool of the breeding nucleus of the Russian population of thoroughbred horses by means of PCR analysis of the E (Extension) locus MC1R gene mutations are presented. The data on the structure of breeding populations from the leading stud farms Voskhod and Oros with regard to color phenotypes as well as genotype and allele frequencies are presented. The population structure parameters are discussed with respect to possible specific features of microevolution processes.

Animals↗
PubMed2000

Georgian and kurd mtDNA sequence analysis shows a lack of correlation between languages and female genetic lineages.

Mitochondrial DNA sequences from Georgians and Kurds were analyzed in order to test the possible correlation between female lineages and languages in these two neighboring West Eurasian groups. Mitochondrial sequence pools in both populations are very similar despite their different linguistic and prehistoric backgrounds. Both populations present mtDNA lineages that clearly belong to the European gene pool, as shown by 1) similar nucleotide and sequence diversities; 2) a large number of sequences shared with the rest of European samples; 3) nonsignificant genetic distances; and 4) classification of the present lineages into the major European mtDNA haplogroups already described. The outlier position of the populations from the Caucasus according to classical genetic markers is not recognized in the present Georgian mtDNA sequence pool. This result suggests that the differentiation of mtDNA sequences in West Eurasia and the outlier features of Caucasian populations should be attributed to different processes. Moreover, the putative linguistic relationship between Caucasian groups and the Basques, another outlier population within Europe for classical genetic markers, is not detected by the analysis of mtDNA sequences.

Adult↗
PubMed1993

Should we change the human genome?

Should we change the human genome? The most general arguments against changing the human genome are here in focus. Distinctions are made between positive and negative gene therapy, between germ-line and somatic therapy, and between therapy where the intention is to benefit a particular individual (a future child) and where the intention is to benefit the human gene-pool. Some standard arguments against gene-therapy are dismissed. Negative somatic therapy is not controversial. Even negative, germ-line therapy is endorsed, if the intention is to cure a certain individual (a future child). In rare cases, positive therapy on somatic cells may be warranted. Germ-line therapy may become a valuable method of preventing harm, through 'genetic vaccination'. If safe methods evolve, it is harmless (though vain), to try to achieve more ambitious goals. Prospective parents should not be prevented from exercising this harmless kind of parental authority. The paper concludes: There is a moral limit to how much we ought to manipulate the human genome, however. We ought not to jeopardize the continued existence of mankind. We ought not to develop methods of germ-line therapy intended in a radical manner to improve human nature, and we ought to leave to prospective parents to decide in individual cases what kind of intervention shall take place.

Biological Evolution↗
PubMed2004

Association between longevity and cytokine gene polymorphisms. A study in Sardinian centenarians.

BACKGROUND AND AIMS: Human longevity seems to be directly correlated with optimal functioning of the immune system, suggesting that some genetic determinants of longevity reside in those polymorphisms for the immune system genes which regulate immune-inflammatory responses, in particular cytokine gene polymorphisms. The frequency of -174C single nucleotide polymorphism (SNP) in the promoter region of the interleukin (IL)-6 gene is increased in Italian male centenarians. Moreover, the frequency of -1082G SNP at the 5' flanking region of the IL-10 gene coding sequence is increased among male centenarians, and that of +874A SNP at the interferon (IFN)-gamma gene was found more frequently in female centenarians. These findings indicate that different alleles at different cytokine gene codings for pro- (IL-6, IFN-gamma) or anti-inflammatory (IL-10) cytokines may affect the individual life-span expectancy, influencing the type and intensity of immune-inflammatory responses against environmental stressors. METHODS: In the present study, we analyzed these IL-6, IL-10 and IFN-gamma gene polymorphisms in 112 (36 male, 76 female) centenarians from the island of Sardinia, whose population shows a genetic background quite different from that of mainland Italy, as well as in 137 sixty-year-old controls from the same geographic area. RESULTS: No significant differences were observed on analyzing IL-6, IL-10 and IFN-gamma polymorphism frequencies among centenarians and controls, either on the whole and when the data were analyzed according to gender. CONCLUSIONS: These data indicate that gene polymorphisms of cytokines playing a major regulatory role in the inflammatory response do not affect life expectancy in the Sardinian population. Thus, cytokine/longevity associations have a population-specific component, being affected by the population-specific gene pool as well as by gene-environment interactions, behaving as survival rather than longevity genes.

Aged↗
PubMed1999

Growth Performance and Gonadal Development of Growth Enhanced Transgenic Tilapia Oreochromis niloticus (L.) Following Heat-Shock-Induced Triploidy.

Triploid induction offers a way of considerably reducing fertility in fish, and could therefore be employed to help ensure that any adverse environmental impact of transgenic fish was markedly less. In order to produce sterile growth-enhanced transgenic fish, we have induced triploidy in two lines of transgenic tilapia. Growth performance and gonadal development were analyzed following triploidization by heat shock. Ploidy status was confirmed by nuclear size measurement of erythrocytes. Erythrocytes of triploids were found to be 1.5 times larger than diploids. Observations of growth enhancement and gonadal development were made on diploids and triploids from both transgenic and nontransgenic full sibling batches. In both lines, transgenic diploids were superior in growth performance, followed by transgenic triploids, nontransgenic diploids, and nontransgenic triploids. Although the testes of transgenic triploids were significantly smaller than those of nontransgenic triploids and nontransgenic diploids, histologically they did not show signs of gross deformation. There were also some spermatozoa present in the testes of some triploids, which could be indicative of reproductive functionality. However, the ovaries were devoid of oocytes, underdeveloped, and deformed in all triploids and were completely nonfunctional. Although the best growth performance was shown by the fertile diploid transgenics, the triploid transgenic females could offer a good option for aquaculture purposes because they showed superior growth performance over the normal wild-type tilapias with the advantage of sterility to ensure nonhybridization and noncontamination with the local gene pool. However, careful monitoring of potential gene flow would be required prior to commercial use.

Journal Article↗
PubMed2003

The sweet pepper ferredoxin-like protein (pflp) conferred resistance against soft rot disease in Oncidium orchid.

Genetic engineering to date has not been used to introduce disease resistance genes into the orchid gene pool. The ferredoxin-like protein gene originally isolated from sweet pepper is thought to function as a natural defense against infection due to its antimicrobial properties. Hence it was reasoned that introduction of this gene might produce Oncidium plants resistant to Erwinia carotovora, the causal agent for the soft rot disease. An expression vector containing sweet pepper ferredoxin-like protein (pflp) cDNA, hph and gusA coding sequence was successfully transformed into protocorm-like bodies (PLBs) of Oncidium orchid, using Agrobacterium tumefaciens strain EHA105. A total of 17 independent transgenic orchid lines was obtained, out of which six transgenic lines (beta-glucuronidase (GUS) positive) were randomly selected and confirmed by Southern, northern and western blot analyses. A bioassay was conducted on the transgenic lines. Transgenic plants showed enhanced resistance to E. carotovora, even when the entire plant was challenged with the pathogen. Our results suggest that pflp may be an extremely useful gene for genetic engineering strategies in orchids to confer resistance against soft rot disease.

Capsicum↗
PubMed2003

Colonia Tovar: the history of a semi-isolated Venezuelan population of German ancestry described by HLA class I genes.

The history of Colonia Tovar is very complex, being the home of descendants of only a small fraction of immigrants arriving to the South American continent from a specific region of Germany, with a restricted number of founders, small population size and consanguineous mating, experiencing isolation for 100 years, with later migrations, a low rate of population growth and a high mean number of children per couple. How complex is its genetic structure? Do the highly polymorphic HLA genes reflect its history and confirm the story of this population described by other genes? Several studies have been made in this population, but we describe for the first time the HLA Class I variability in the population of Colonia Tovar using PCR-SSOP. Random genetic drift, founder effect and gene flow could explain the HLA allele and haplotype frequencies observed in this population but alleles at the class I loci were insufficient to identify the German origin of the community established through history. This agrees with findings obtained testing other genetic systems (ACP, AK, ESD, G6PD, GLO, PGM, PGD, ALB, CP, HP, TF), but the HLA-typing results indicate that the original gene pool has been diluted due to gene flow from the surrounding Mestizo population.

Adolescent↗
PubMed2006

Origin and evolution of the mitochondrial aminoacyl-tRNA synthetases.

Many theories favor a fusion of 2 prokaryotic genomes for the origin of the Eukaryotes, but there are disagreements on the origin, timing, and cellular structures of the cells involved. Equally controversial is the source of the nuclear genes for mitochondrial proteins, although the alpha-proteobacterial contribution to the mitochondrial genome is well established. Phylogenetic inferences show that the nuclearly encoded mitochondrial aminoacyl-tRNA synthetases (aaRSs) occupy a position in the tree that is not close to any of the currently sequenced alpha-proteobacterial genomes, despite cohesive and remarkably well-resolved alpha-proteobacterial clades in 12 of the 20 trees. Two or more alpha-proteobacterial clusters were observed in 8 cases, indicative of differential loss of paralogous genes or horizontal gene transfer. Replacement and retargeting events within the nuclear genomes of the Eukaryotes was indicated in 10 trees, 4 of which also show split alpha-proteobacterial groups. A majority of the mitochondrial aaRSs originate from within the bacterial domain, but none specifically from the alpha-Proteobacteria. For some aaRS, the endosymbiotic origin may have been erased by ongoing gene replacements on the bacterial as well as the eukaryotic side. For others that accurately resolve the alpha-proteobacterial divergence patterns, the lack of affiliation with mitochondria is more surprising. We hypothesize that the ancestral eukaryotic gene pool hosted primordial "bacterial-like" genes, to which a limited set of alpha-proteobacterial genes, mostly coding for components of the respiratory chain complexes, were added and selectively maintained.

Alphaproteobacteria↗
PubMed2002

[Genetic diversity of protein markers in sheep population from Ukraine].

Based on polymorphism of genes for antigen factors of six blood-group systems and four blood protein loci, genetic structure and the main variation parameters were studied in three sheep breeds and three sheep breed types constituting the basis of purebred sheep resources in Ukraine. Specific features of the distribution of genotypes and alleles of polymorphic loci were determined in each of the studied sheep groups depending on their origin and production type. The molecular-genetic markers used in the analysis of the genetic relationships between the sheep breeds and breed types were shown to objectively reflect their breeding history and evolution. Integrally, each of the studied gene pools had a specific profile of gene frequencies reflecting breeding specificity, breed history, and genetic differentiation of breeds.

Animals↗
PubMed2006

Recent epidemiology and ecology of influenza A viruses in avian species in Europe and the Middle East.

There have been at least ten distinct outbreaks of LPAI or HPAI in poultry caused by H5 or H7 viruses in the last eight years in Europe and the Middle East. There appears to be an increased occurrence of such episodes consistent with global trends. As a result, surveillance systems have been enhanced to facilitate early detection of infection in poultry, together with active surveillance of wild bird populations. These complementary activities have resulted in the detection of a number of viruses in wild bird populations, including some with high genetic similarity to newly detected viruses in poultry, for example, H7N3 in Italy and H7N7 in the Netherlands. Furthermore, there is evidence for continued circulation of H5 and H7 viruses in wild Anseriformes, thereby presenting a real and current threat for the introduction of viruses to domestic poultry, especially those reared in outdoor production systems. Viruses of H9N2 subtype continue to circulate widely in the Middle East and are associated with significant disease problems in poultry. The epidemiology has the potential to be complicated further by introduction of novel viruses through illegal importation of captive birds, such as was detected with H5N1 in Belgium in 2004. Continual genetic exchange in the avian virus gene pool and independent evolution of all gene segments either within an individual host species or among wild bird hosts suggests that these viruses are not in evolutionary stasis in the natural reservoir.

Animals↗
PubMed1988

Common genetic pools between human populations.

A further inquiry on modern human origins, based on common genetic pool surveys of rigorously selected population samples and highly informative immunological polymorphisms, provides new evidence of an Occidental-Oriental population split as the origin of human gene pool divergences. The most likely ancestral genetic profile is discussed in the context of the debate raised by preliminary DNA restriction fragment length polymorphism studies, which contradict the conclusions drawn from classical blood group analyses.

Biological Evolution↗
PubMed1991

[Genetic polymorphism in the Karelian population].

Distribution of the genetic markers of blood groups (AB0, MNSs, Rhesus, P, Lewis, Duffy, Kell-Cellano, Kell-Kp, Kell-Sutter, Kidd, Lutheran); of serum proteins (Hp, Tf, Gc, C'3, Pi); red-cell enzymes (6-PGD, EsD, GLO, AcP, subtypes of PGM) was studied in Karels from the South part of Karelian ASSR. The results of comparison of Karels with the other finno-ugric peoples revealed peculiarities of gene pool in Karelian population.

Adult↗
PubMed2002

Phylogeographic analysis of mtDNA variation in four ethnic populations from Yunnan Province: new data and a reappraisal.

Two sets of mitochondrial DNA (mtDNA) hypervariable segment I (HVS-I) data from four ethnic populations (Tibetan, Va, Dai, and Lahu) from Yunnan Province, China, were analyzed here by using phylogeographic methods. The results suggest that more attention should be paid to sampling methodology when addressing the genetic relationship and affinity among ethnic populations. Comparison of related data from different labs may serve as a check for the credibility of the data and will help discern the origin of the ethnic populations. Generally, Tibetan populations have more north-prevalent haplogroups (clades of the mtDNA phylogeny), while Dai and Lahu populations have high frequencies of south-prevalent haplogroups. The Vas, although autochthonous according to historical records, show signs of gene admixtures from northern and southern populations, for they harbor high frequencies of the south-prevalent haplogroup F and the north-prevalent haplogroup D as well as other northern mtDNA lineages such as M9 and G2a. The consanguineous marriage customs of the Lahu, together with possible genetic drift during this group's historical migration, left a conspicuous genetic imprint on its current gene pool.

Asian People↗
PubMed2001

Genetics and the population history of Europe.

Analysis of genetic variation among modern individuals is providing insight into prehistoric events. Comparisons of levels and patterns of genetic diversity with the predictions of models based on archeological evidence suggest that the spread of early farmers from the Levant was probably the main episode in the European population history, but that both older and more recent processes have left recognizable traces in the current gene pool.

Alleles↗
PubMed2002

Cloning advances and challenges for conservation.

Although controversy surrounds cloning efforts, the cloning of animals to assist efforts to preserve genetic variation in support of endangered species conservation efforts has attracted serious interest. A recent report by Loi et al. describing the cloning of a mouflon (a species of wild sheep) in a domestic sheep surrogate points to potential conservation opportunities and additional challenges in the evaluation of appropriate technologies for present and future efforts to conserve gene pools of endangered species.

Animals↗
PubMed2001

Genetic differentiation in South Amerindians is related to environmental and cultural diversity: evidence from the Y chromosome.

The geographic structure of Y-chromosome variability has been analyzed in native populations of South America, through use of the high-frequency Native American haplogroup defined by the DYS199-T allele and six Y-chromosome-linked microsatellites (DYS19, DYS389A, DYS389B, DYS390, DYS391, and DYS393), analyzed in 236 individuals. The following pattern of within- and among-population variability emerges from the analysis of microsatellite data: (1) the Andean populations exhibit significantly higher levels of within-population variability than do the eastern populations of South America; (2) the spatial-autocorrelation analysis suggests a significant geographic structure of Y-chromosome genetic variability in South America, although a typical evolutionary pattern could not be categorically identified; and (3) genetic-distance analyses and the analysis of molecular variance suggest greater homogeneity between Andean populations than between non-Andean ones. On the basis of these results, we propose a model for the evolution of the male lineages of South Amerindians that involves differential patterns of genetic drift and gene flow. In the western part of the continent, which is associated with the Andean area, populations have relatively large effective sizes and gene-flow levels among them, which has created a trend toward homogenization of the gene pool. On the other hand, eastern populations-settled in the Amazonian region, the central Brazilian plateau, and the Chaco region-have exhibited higher rates of genetic drift and lower levels of gene flow, with a resulting trend toward genetic differentiation. This model is consistent with the linguistic and cultural diversity of South Amerindians, the environmental heterogeneity of the continent, and the available paleoecological data.

Cultural Diversity↗
PubMedDate not supplied

Beta-globin gene cluster haplotypes as evidence of African gene flow to the northeastern coast of Venezuela.

In order to study the origin of mutation HBB*S in Sucre and Anzoátegui states and the genetic affinities of these Venezuelan populations with other human groups, the beta-globin gene cluster haplotypes were determined for 28 sickle cell and/or S-beta thalassemia patients and for 37 individuals with normal hematological parameters. Bantu, Benin, Senegal, and atypical haplotypes were identified in 50%, 36%, 2%, and 12% of the HBB*S chromosomes, respectively. Similar results have been published for Venezuelan patients from the central states, but a different trend is shown in a publication based on a group of patients from different regions of the country. For HBB*A, haplotype 2 (+ - - - -), characteristic of non-African groups, was the most common (39%), followed by haplotype 3 (- - - - +) of African origin, and haplotype 6 (- + + - +), also typical of non-Africans. The results reveal a high level of admixture of the Sucre-Anzoátegui population. The importance of specific conditions which have acted differently in the Venezuelan populations, such as founder effect, genetic drift, isolation, and endogamy are discussed. Genetic distances between the Sucre-Anzoátegui sample and several other human populations calculated on the basis of the HBB*S and HBB*A haplotypes revealed similar results, the closest genetic relationships being observed in relation to Bantu-speaking groups. These results confirm the utility of the beta-globin haplotypes for population studies and contribute to knowledge of the Venezuelan gene pool.

Adolescent↗