68 research outputs found
Biodiversity of 52 chicken populations assessed by microsatellite typing of DNA pools
No full textAbstract In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken.</p
Reassessing the mitochondrial DNA evidence for migration at the Mesolithic–Neolithic transition
No full textDetermination of linkage disequilibrium region suggests association of the ancient haplotype, hX with neural function
No full textModern human populations are known to contain "ancient haplotypes" that originated from archaic humans by hybridization. Some of them had been reported before the development of human genomic diversity databases, such as HapMap. Consequently, some of them have no information about linkage disequilibrium (LD) regions. Because genetic information within LD is tightly linked, to know LD region containing ancient haplotypes will be useful to estimate basic parameters of admixture events, and to infer biological functions that linked with the ancient haplotypes. One of these ancient haplotypes, haplotype X (_hX_) was found in a 10.1 kb-region located on Xp11.22, which diverged at 1.4 M years ago, with low diversity within the cluster in gene genealogy and worldwide distribution in low frequency. We determined the LD region around the ancient haplotypes using LD information obtained in the HapMap project. The LD determination presents that the LD region surrounding the _hX_ is stable and contains genic regions that may associate with neural and brain functions
In search of the genetic footprints of Sumerians: a survey of Y-chromosome and mtDNA variation in the Marsh Arabs of Iraq
No full textBackground
For millennia, the southern part of the Mesopotamia has been a wetland region generated by the Tigris and Euphrates rivers before flowing into the Gulf. This area has been occupied by human communities since ancient times and the present-day inhabitants, the Marsh Arabs, are considered the population with the strongest link to ancient Sumerians. Popular tradition, however, considers the Marsh Arabs as a foreign group, of unknown origin, which arrived in the marshlands when the rearing of water buffalo was introduced to the region.
Results
To shed some light on the paternal and maternal origin of this population, Y chromosome and mitochondrial DNA (mtDNA) variation was surveyed in 143 Marsh Arabs and in a large sample of Iraqi controls. Analyses of the haplogroups and sub-haplogroups observed in the Marsh Arabs revealed a prevalent autochthonous Middle Eastern component for both male and female gene pools, with weak South-West Asian and African contributions, more evident in mtDNA. A higher male than female homogeneity is characteristic of the Marsh Arab gene pool, likely due to a strong male genetic drift determined by socio-cultural factors (patrilocality, polygamy, unequal male and female migration rates).
Conclusions
Evidence of genetic stratification ascribable to the Sumerian development was provided by the Y-chromosome data where the J1-Page08 branch reveals a local expansion, almost contemporary with the Sumerian City State period that characterized Southern Mesopotamia. On the other hand, a more ancient background shared with Northern Mesopotamia is revealed by the less represented Y-chromosome lineage J1-M267*. Overall our results indicate that the introduction of water buffalo breeding and rice farming, most likely from the Indian sub-continent, only marginally affected the gene pool of autochthonous people of the region. Furthermore, a prevalent Middle Eastern ancestry of the modern population of the marshes of southern Iraq implies that if the Marsh Arabs are descendants of the ancient Sumerians, also the Sumerians were most likely autochthonous and not of Indian or South Asian ancestry
Prehistoric migration in Europe: Strontium isotope analysis of Early Neolithic skeletons
No full textChronic virus infections supress atopy but not asthma in a set of children from a large Latin American city: a cross-section study.
No full textBACKGROUND: The prevalence of allergic diseases has increased over recent decades in affluent countries, but remains low in rural populations and some non-affluent countries. An explanation for these trends is that increased exposure to infections may provide protection against the development of allergy. In this work we investigated the association between exposure to viral infections in children living in urban Brazil and the prevalence of atopy and asthma. METHODS: School age children living in poor neighborhoods in the city of Salvador were studied. Data on asthma symptoms and relevant risk factors were obtained by questionnaire. Skin prick tests (SPTs) were performed to seven aeroallergens, and specific IgE was measured to four of these. Viral infections were determined by the presence of specific IgG in serum to Herpes simplex (HSV), Herpes zoster (HZV), Epstein-Barr (EBV), and Hepatitis A (HAV) viruses. RESULTS: A total of 644 (49.7%) children had at least one allergen-specific IgE> 0.35 kU/L and 489 (37.7%) had specific IgE> 0.70 kU/L. A total of 391 (30.2%) children were skin test positive (SPT+), and 295 (22.8%) children were asthmatic. The seroprevalence of viral infections was 88.9% for EBV, 55.4% for HSV, 45.5% for VZV and 17.5% for HAV. Negative associations were observed between SPT+ and HSV (OR = 0.64, CI = 0.51, 0.82) and EBV (OR = 0.63, CI = 0.44, 0.89) infections, but no associations were seen between viral infections and the presence of allergen-specific IgE or asthma. CONCLUSION: These data do not support previous data showing a protective effect of HAV against atopy, but did show inverse associations between SPT+ (but not specific IgE+) and infections with HSV and EBV. These findings suggest that different viral infections may protect against SPT+ in different settings and may indicate an immunoregulatory role of such infections on immediate hypersensitivity responses. The data provide no support for a protective effect of viral infections against asthma in this population
Aproximació a les migracions històriques a través de l'estudi dels cognoms. Catalunya, 1497-1601
No full textTreball de Recerca del Màster en Estudis Territorials i de la Població (UAB), codirigit per Anna Cabré i Joana M. Pujadas. Bellaterra, 5 de juliol 2011.L'estudi analitza els fluxos migratoris esdevinguts a Catalunya durant la primera meitat del segle XVI, a través d'un mètode d'estimació indirecta, l'anàlisi dels cognoms continguts en els fogatges de 1497 i 1553. La recerca es centra en l'anàlisi descriptiu de les dades, focalitzant-se especialment en els cognoms més comuns de l'època. Així mateix, s'ha analitzat la distribució espacial d'aquests, entre 1497 i 1553, cartografiant la seva evolució al llarg del temps. Finalment, el grau d'interrelació entre les distintes demarcacions territorials de la Catalunya moderna (col·lectes) ha estat establert mitjançant l'aplicació del coeficient de Chen i Cavalli-Sforza (1983).El artículo analiza los flujos migratorios acaecidos en Cataluña durante la primera mitad del siglo XVI a través de un método de estimación indirecta como es el análisis de los apellidos contenidos en los recuentos de fuegos u hogares (fogajes) de 1497 y 1553. El estudio se centra en el análisis descriptivo de los datos, focalizándose en los apellidos más comunes de la época. Así mismo, se ha analizado la distribución espacial de éstos entre 1497 y 1553, cartografiando su evolución a lo largo del tiempo. Finalmente, el grado de interrelación entre las distintas demarcaciones territoriales de la Cataluña moderna (col·lectes) ha sido establecido a través de la aplicación del coeficiente de Chen y CavalliSforza (1983).This paper aims to identify migration flows during the first half of the XVI century. To achieve this goal we analyze population movements using the distribution and emergence of family names. For that purpose the Catalan household tax counts (fogatges) of 1497 and 1553 are used. These counts were made for fiscal purposes and collect each family unit (household or fireplace) of the region by villages. Firstly we conduct a descriptive analysis of the data, focusing on the most common surnames of that period. Secondly, the spatial distribution of these surnames among the two aforementioned periods is analyzed, mapping their distribution throughout time. Finally, we concern on the degree of interrelation among different regions of Catalonia in that time (col·lectes) applying the coefficient of Chen and Cavalli-Sforza (1983)
Aproximació a les migracions històriques a través de l'estudi dels cognoms : Catalunya, 1497-1601
No full textTreball de Recerca del Màster en Estudis Territorials i de la Població (UAB), codirigit per Anna Cabré i Joana M. Pujadas. Bellaterra, 5 de juliol 2011.L'estudi analitza els fluxos migratoris esdevinguts a Catalunya durant la primera meitat del segle XVI, a través d'un mètode d'estimació indirecta, l'anàlisi dels cognoms continguts en els fogatges de 1497 i 1553. La recerca es centra en l'anàlisi descriptiu de les dades, focalitzant-se especialment en els cognoms més comuns de l'època. Així mateix, s'ha analitzat la distribució espacial d'aquests, entre 1497 i 1553, cartografiant la seva evolució al llarg del temps. Finalment, el grau d'interrelació entre les distintes demarcacions territorials de la Catalunya moderna (col·lectes) ha estat establert mitjançant l'aplicació del coeficient de Chen i Cavalli-Sforza (1983).El artículo analiza los flujos migratorios acaecidos en Cataluña durante la primera mitad del siglo XVI a través de un método de estimación indirecta como es el análisis de los apellidos contenidos en los recuentos de fuegos u hogares (fogajes) de 1497 y 1553. El estudio se centra en el análisis descriptivo de los datos, focalizándose en los apellidos más comunes de la época. Así mismo, se ha analizado la distribución espacial de éstos entre 1497 y 1553, cartografiando su evolución a lo largo del tiempo. Finalmente, el grado de interrelación entre las distintas demarcaciones territoriales de la Cataluña moderna (col·lectes) ha sido establecido a través de la aplicación del coeficiente de Chen y CavalliSforza (1983).This paper aims to identify migration flows during the first half of the XVI century. To achieve this goal we analyze population movements using the distribution and emergence of family names. For that purpose the Catalan household tax counts (fogatges) of 1497 and 1553 are used. These counts were made for fiscal purposes and collect each family unit (household or fireplace) of the region by villages. Firstly we conduct a descriptive analysis of the data, focusing on the most common surnames of that period. Secondly, the spatial distribution of these surnames among the two aforementioned periods is analyzed, mapping their distribution throughout time. Finally, we concern on the degree of interrelation among different regions of Catalonia in that time (col·lectes) applying the coefficient of Chen and Cavalli-Sforza (1983)
A Measurement of alpha-s from jet rates at the Z0 resonance
No full textWe have determined the strong coupling alpha(s) from measurements of jet rates in hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. Using six collinear and infrared safe jet algorithms we compared our data with the predictions of QCD calculated up to second order in perturbation theory, and also with resummed calculations. We find alpha(s)(M(Z)2)=0.118+/-0.002(stat)+/-0.003(syst) +/-0.010 (theory), where the dominant uncertainty is from uncalculated higher order contributions
Search For Radiative B-meson Decays
No full textThe Crystal Ball detector at the e+ e- storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b --> s-gamma. No monoenergetic gamma-lines have been found in the inclusive photon spectrum from UPSILON(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR (B--> gamma-X) < 2.8 x 10(-3), at 90% confidence level for the mass range 892 MeV less-than-or-equal-to M(X) less-than-or-equal-to 2045 MeV
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