1,721,109 research outputs found
Bertranpetit (J) — Human mitochondrial DNA variation and the origin of Basque
No full textHoudaille Jacques. Bertranpetit (J) — Human mitochondrial DNA variation and the origin of Basque. In: Population, 50ᵉ année, n°3, 1995. pp. 871-872
Bertranpetit (J) — Human mitochondrial DNA variation and the origin of Basque
No full textHoudaille Jacques. Bertranpetit (J) — Human mitochondrial DNA variation and the origin of Basque. In: Population, 50ᵉ année, n°3, 1995. pp. 871-872
The Mediterranean paradox for susceptibility factors in coronary heart disease extends to genetics
No full textThe incidence of coronary heart disease (CHD) shows a North to South gradient in Europe. We tested whether that
gradient could be accounted for by the distribution of putative susceptibility genotypes. We correlated the published
frequencies of susceptibility genotypes for the genes most often associated with CHD (ACE, AGT, APOE, F2, F5,
MTHFR, PON1, and SERPINE1) with the incidence of the disease, controlling for the effects of smoking, systolic
pressure, total cholesterol, and body-mass index. In three polymorphisms a negative correlation between the incidence
of CHD and the frequency of a suceptibility genotype was observed. For ACE this correlation was significantly negative
even when discounting classical susceptibility factors. This suggests that some alleles described as susceptibility factors
cannot account for disease incidence at the population level. A genetic component must be added to the “Mediterranean
paradox”: genetic variants deemed to be risk factors for CHD show a geographical pattern uncorrelated with the disease
incidence. This pattern can be understood from the history of populations which has shaped the genetic diversity of the
European populations in North-South clines, similar to what is observed for CHD incidence, which will tend to create
spurious correlations with polymorphisms related, or not related, to the disease
Reconstruction of prehistory on the basis of genetic data
No full textIn their letter, Torroni et al. (2000) express a radical
disagreement with the assumptions, methods, and conclusions
of Simoni et al.’s (2000) article. We think that
their many criticisms can be reduced to four points:
1. Haplogroups have been incorrectly defined, and
therefore the spatial autocorrelation analysis (SAAP) of
their frequencies is flawed;
2. Aside from these errors, the frequencies of haplogroup
J and of superhaplogroup JT do not match previous
reports;
3. Only 22 polymorphic sites have been considered,
and therefore the results of AIDA are flawed;
4. Meaningful patterns of mtDNA diversity can only
be identified by the analysis of the distributions of recent
mutations
Do Basque- and Caucasian-speaking populations share non-Indo-European ancestors?
No full textGenetic evidence is consistent with the view that the Indo-European languages were propagated in Europe by the diffusion of early farmers. The existence of phylogenetic relationships between European populations speaking other languages has been proposed on linguistic and archaeological grounds, and is here tested by analyzing allele frequencies at ten polymorphic protein and blood group loci. Genetic distances between speakers of Basque and Caucasian languages are compared with those between controls, i.e. contiguous populations speaking Indo-European and Altaic. Although some statistical tests show an excess of genetic similarity between Basque and South Caucasian speakers, most results do not support their common origin. If the Basques and the Caucasian-speaking populations share common ancestors, recent evolutionary phenomena must have caused divergence between them, so that their gene frequencies do not appear more similar now than those of random pairs of populations separated by the same geographic distance
Geographic homogeneity and non-equilibrium patterns of mtDNA sequences in Tuscany, Italy
No full textThe geographical distribution of 49 mtDNA sequences from 22 localities in Southern Tuscany, Italy, was studied by molecular analysis of variance, by a new spatial autocorrelation statistic specifically designed for sequence data and by reconstructing genealogies of haplotypes. All these methods indicated a high homogeneity of populations. Nevertheless, genetic variability showed significant departure from equilibrium expectations, in agreement with the predicted effects of a population expansion. We suggest that a past population expansion that was probably associated with a migrational wave and with local gene flow between localities prevented spatial structuring in Southern Tuscany
Sequence diversity of the control region of mitochondrial DNA in tuscany and its implications for the peopling of Europe
No full textThe control region of mitochondrial DNA has been widely studied in various human populations. This paper reports sequence data for hypervariable segments 1 and 2 of the control region from a population from southern Tuscany (Italy). The results confirm the high variability of the control region, with 43 different haplotypes in 49 individuals sampled. The comparison of this set of data with other European populations allows the reconstruction of the population history of Tuscany. Independent approaches, such as the estimation of haplotype diversity, mean pairwise differences, genetic distances and discriminant analysis, place the Tuscan sample in an intermediate position between sequences from culturally or geographically isolated regions of Europe (Sardinia, the Basque Country, Britain) and those from the Middle East. In spite of the remarkable genetic homogeneity in Europe, a degree of variability is shown by local European populations and homogeneity increases with the relative isolation of the population. The pattern of mitochondrial variation in Tuscany indicates the persistence of an ancient European component subsequently enriched by migrational waves, possibly from the Middle East. (C) 1998 Wiley-Liss, Inc
Geographic patterns of mtDNA diversity in Europe
No full textGenetic diversity in Europe has been interpreted as a
reflection of phenomena occurring during the Paleolithic
(»45,000 years before the present [BP]), Mesolithic
(»18,000 years BP), and Neolithic (»10,000 years BP)
periods. A crucial role of the Neolithic demographic
transition is supported by the analysis of most nuclear
loci, but the interpretation of mtDNA evidence is controversial.
More than 2,600 sequences of the first hypervariable
mitochondrial control region were analyzed
for geographic patterns in samples from Europe, the
Near East, and the Caucasus. Two autocorrelation statistics
were used, one based on allele-frequency differences
between samples and the other based on both sequence
and frequency differences between alleles. In the
global analysis, limited geographic patterning was observed,
which could largely be attributed to a marked
difference between the Saami and all other populations.
The distribution of the zones of highest mitochondrial
variation (genetic boundaries) confirmed that the Saami
are sharply differentiated from an otherwise rather homogeneous
set of European samples. However, an area
of significant clinal variation was identified around the
Mediterranean Sea (and not in the north), even though
the differences between northern and southern populations
were insignificant. Both a Paleolithic expansion
and the Neolithic demic diffusion of farmers could have
determined a longitudinal cline of mtDNA diversity.
However, additional phenomena must be considered in
both models, to account both for the north-south differences
and for the greater geographic scope of clinal
patterns at nuclear loci. Conversely, two predicted consequences
of models of Mesolithic reexpansion from glacial
refugia were not observed in the present study
Les traits non métriques et descriptifs du crâne déformé
No full textDISCONTINUOUS AND DESCRIPTIVE MORPHOLOGICAL TRAITS IN ARTIFICIALLY DEFORMED CRANIA Summary. — Some discontinuous and descriptive morphological traits are analyzed comparatively in artificially deformed and undeformed skulls in order to ascertain the possible effects of deformation on epigenetic traits and to determine which parts of the skull are really affected by deformative practices. 82 deformed and 24 undeformed skulls from the Bolivian high plateau are analyzed for sutural complexity, for 10 discontinuous and 23 descriptives traits. First of all the relationship between the presence of deformation and its types, trepanation, age and sex are examined. Patterns of sutural complexity and the presence of supernumerary sutural bones are not modified by artificial deformation. None of the discontinuous traits are influenced by the fact of deformation, which enhances their anthropological interest. Neither the descriptive traits of the basilar and facial regions nor the usually-employed morphological traits for sexual diagnosis, which have normal development after the use of deformatory apparatus, are influenced by deformation.Résumé. — Des traits non-métriques et descriptifs sont analysés de façon comparative dans une série de crânes déformés artificiellement et une autre de non-déformés pour déduire le possible effet de la déformation sur les caractères épigénétiques et délimiter de façon précise la région crânienne affectée par la pratique déformatrice. 82 crânes déformés et 24 non-déformés provenants du haut-plateau bolivien sont analysés pour la complication des sutures, pour 10 caractères non-métriques et pour 23 caractères descriptifs. D'abord on a établi le rapport entre la présence de déformation et ses types, la trépanation, l'âge et le sexe. La complication des sutures et la formation des os surnuméraires ne sont pas modifiées par la pratique déformatrice. Aucun des caractères non-métriques étudiés n'est influencé par l'existence de déformation, ce qui enlèverait son intérêt anthropologique. Aucun des caractères descriptifs des régions basilaire et faciale ne sont influencés par la présence de déformation, non plus que les caractères usuellement employés pour le diagnostic sexuel, lesquels auront un développement normal après l'usage des appareils déformateurs.Vives E., Bertranpetit J. Les traits non métriques et descriptifs du crâne déformé. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, XIV° Série. Tome 3 fascicule 4, 1986. pp. 237-248
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