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A Rodríguez-Larralde

Publications and source records attributed to A Rodríguez-Larralde.

12 recordsLinked to original sources
PubMed2001

Extended HLA haplotypes in a Carib Amerindian population: the Yucpa of the Perija Range.

Eleven MHC loci haplotypes have been defined among a Carib speaking Amerindian population; the Yucpa, inhabiting the northern section of the Perija Range, on the limits between Colombia and Venezuela. This tribe has been known with the name of "Motilones mansos" and is located close to the Chibcha-Paeze speaking Bari or "Motilones bravos." Seventy-three full blooded Yucpa living at the villages of Aroy, Marewa, and Peraya, were selected using a genealogy previously collected by an anthropologist and tested for Bf-C4AB complement allotypes and by serology, high resolution PCR-SSO and SBT typing for HLA class 1 and class 2 alleles. Combinations of 6 HLA-A, 6 HLA-B, 5 HLA-C, 1 Bf, 3 C4AB, 3 DQA1, 3DQB1 and 2 DPA1 and 2 DPB1 alleles present in this population originate 17 different haplotypes, 3 of which represent 63% of the haplotypic constitution of the tribe. The presence of 13 individuals homozygous for 11-loci haplotypes corroborates the existence of the following allelic combinations: DRB1*0411 DQA1*03011 DQB1*0302 DPA1*01 DPB1*0402 with HLA-A*6801 C*0702 B*3909 BfS C4 32 (f = 0.3372) or with A*0204 C*0702 B*3905 (f = 0.1977) and a third haplotype which differs only in DRB1*0403 and A*2402 (f = 0.0930). The results demonstrate the isolation of the tribe and the existence of high frequencies of a reduced number of "Amerindian" ancestral and novel class 1 and class 2 alleles (B*1522, DRB1*0807) with significant linkage disequilibria. These results will be useful to test the hypothesis that differentiation of Amerindian tribal groups will have to rely on haplotypes and micropolymorphism rather than allelic lineage frequencies due to the uniformity shown thus far by the putative descendants of the original Paleo-Indians.

Colombia↗
PubMed1997

Isonymy structure of Sucre and Táchira, two Venezuelan states.

The isonymy structure of two Venezuelan states, Sucre and Táchira, is described using the surnames of the Register of Electors updated in 1991. The frequency distribution of surnames pooled together by sex was obtained for the 57 counties of Sucre and the 52 counties of Táchira, based on total population sizes of 158,705 and 160,690 individuals, respectively. The coefficient of consanguinity resulting from random isonymy (phi ii), Karlin and McGregor's ni (identical to v), and the proportion of the population included in surnames represented only once (estimator A) and in the seven most frequent surnames (estimator B) were calculated for each county. RST, a measure of microdifferentiation, was estimated for each state. The Euclidean distance between pairs of counties within states was calculated together with the corresponding geographic distances. The correlations between their logarithmic transformations were significant in both cases, indicating differentiation of surnames by distance. Dendrograms based on the Euclidean distance matrix were constructed. From them a first approximation of the effect of internal migration within states was obtained. Ninety-six percent of the coefficient of consanguinity resulting from random isonymy is determined by the proportion of the population included in the seven most frequent surnames, whereas between 72% and 88% of Karlin and McGregor's ni for Sucre and Táchira, respectively, is determined by the proportion of population included in surnames represented only once. Surnames with generalized and with focal distribution were identified for both states, to be used as possible indicators of the geographic origin of their carriers. Our results indicate that Táchira's counties, on average, tend to be more isolated than Sucre's counties, as measured by RST, estimator B, and phi ii. Comparisons with the results obtained for other. Venezuelan states and other non-Venezuelan populations are also given.

Emigration and Immigration↗
PubMed1994

Isonymy and the genetic structure of Sicily.

The genetic structure of Sicily was analysed through the distribution of surnames of 758,793 users registered in the Italian Telephone Company, corresponding to 371 communes of the island. Estimates of the coefficient of consanguinity due to random isonymy, of Fisher's a, an indicator of abundance of surnames, and of Karlin-McGregor's v, an indicator of immigration rates, were obtained for each commune. Four different estimates of genetic distance between all possible pairs of communes within each province were also obtained, and their relationship with geographic distance was studied. The logarithmic transformation of Lasker's coefficient of relationship showed correlations with the log of geographic distance which range between -0.78 and -0.40; the strongest, for the province of Catania, was attributed to the presence of Mount Etna, and the weakest, for Palermo, to the high population density of this province.

Bias↗
PubMed1994

Identification of a set of frequent decanucleotides in plants and in animals.

We studied the frequency distribution of 1,048,576 oligonucleotides 10 bp long in a sample of 1.961 Mbase of genes from plants, made of 635 sequences extracted from GenBank 71.0, with the aim of detecting transcription control signals. Among all decamers, 3255, or 0.3%, had a frequency 10 times higher than the mean and were subjected to further statistical analysis. For each of the 3255 decamers (parents), we counted the individual frequencies of the 30 decamers (progeny) differing from the parent by one base mutation, and calculated two variance/mean chi-squares for the progeny, with and without the parent decamer. By studying the distribution of the ratio between the two chi-squares we observed that out of 3255 decamers > 10 times frequent than average, 432 had a chi-square ratio > 1.9. In this residual set, which corresponds to < 0.04 per cent of all possible decamers, only 15 known eukaryotic transcription control elements were found; on the other hand, it included 29 decanucleotides that matched with decanucleotides of a set of Drosophila, 24 with a set from mammals, 13 with a set from yeast and four with a set of viruses--all sets identified with the statistical procedures here described. These decanucloetides are highly repetitive and seem to be present throughout all higher organisms, whereas they are uncommon in mammalian viruses.

Animals↗
PubMed1993

Genetic distance estimated through surname frequencies of 37 counties from the state of Lara, Venezuela.

Genetic distances between all possible pairs of counties (n = 37) in the state of Lara, Venezuela were calculated using surname frequencies and the Euclidean distance as estimator. In general, Euclidean distances were smaller between counties closer together, and the product moment correlation between geographic and Euclidean distances was 0.49 (p < 0.02). The results suggest that, in Lara, geographic distance has been an important determinant of genetic structure, although topography and roadways also have had an important influence upon this structure.

Developing Countries↗
PubMed1990

[Anatomical distribution of subcutaneous body fat in a sample of school children of Los Teques: absolute patterns and familial aggregation].

The absolute patterns of subcutaneous body fat distribution were studied in a sample of school children from Los Teques, Miranda, formed by 222 females and 216 males, with ages between 6 and 17 years. These patterns were obtained based on the means by age and sex of the measurements expressed in millimeters, of 5 skinfolds: tríceps, subscapular, suprailiac, thigh and medial calf. Resemblance between sibs for height, weight and these 5 skinfolds was estimated through an intraclass correlation coefficient based on 100 pairs of sibs. Correlations between 100 random pairs of unrelated subjects were also estimated for these same variables in order to make comparisons between the correlation values obtained when biological relationship exists and when it is absent. The absolute patterns show that females are fatter than males, and that a redistribution of fat from extremities to trunk occurs from adolescence up to adulthood, more evident and taking place earlier in males. The intraclass correlation coefficients between sibs were higher than those between unrelated pairs, for all variables except for medial calf; these tendencies suggest the presence of genetic and/or common environmental factors on the determination of these variables. The highest correlation between sibs was obtained for height; within the five skinfolds, thigh is the one with the highest correlation value, whereas medial calf shows the lowest, suggesting that this is the skinfold with the smallest genetic component in its determination.

Adipose Tissue↗
PubMed1989

Relationship between 17 Venezuelan counties estimated through communality of surnames.

The coefficients of relationship and the Euclidean distances between 17 Venezuelan counties were estimated based on the frequency distribution of surnames obtained from the 1984 Venezuelan register of electors. In general, the coefficients of relationship between counties within the same state were higher than those between counties from different states. Euclidean distances exhibited the opposite relationship. Spearman's correlation coefficients for 136 pairs of counties were estimated between geographic and Euclidean distances (r = 0.41), geographic distance and coefficient of relationship (r = -0.44) and between Euclidean distance and coefficient of relationship (r = -0.48). The effect of partial geographic isolation on the frequency distribution of surnames is shown in the State of Falcón, where an isthmus separates two counties of the peninsula from two others on the mainland, and in Mérida, where the Venezuelan Andes separates three counties from the rest of the country. Our results suggest that Euclidean distances are less influenced by common surnames than the coefficients of relationship. They also indicate that in Venezuela a high proportion of the population has remained sedentary until recently, and this gives rise to the focal distribution of some surnames.

Demography↗
PubMed1987

Metacarpophalangeal pattern profiles in Venezuelan and northern Caucasoid samples compared.

Comparison of hand long-bone lengths and variances in published measurements of North American Caucasoid, Venezuelan, and English individuals, and of their metacarpophalangeal pattern profiles (MPP), revealed systematic differences between samples from infancy through adulthood. The variances of Venezuelan males tend to be larger than those of Americans, especially under 9 years of age. The same trend was observed for females, but to a lesser degree. The English sample showed variance similar to that of Venezuelans and Americans. Below 7 years of age, bones of Venezuelans were longer than those of Americans, except the distal phalanges, which always were longer in the latter, as were all bones after age 17. The index finger's middle and distal phalanges of Americans were relatively longer than the other bones at all ages. Females also showed this general trend, though not as clearly. Venezuelan adults had longer first and second metacarpals and proximal phalanges than the English adult homologs. American adults had all bones longer than those of English adults. The English adults showed a "typical" MPP, characterized by shorter proximal phalanges, both when compared with Venezuelan and with American adults. Genetic rather than environmental causes are likely as an explanation for these differences. This warned us against the indiscriminate use of any "standard" sample from a different population to establish objective profile patterns and sizes in abnormal cases, as illustrated with one example.

Adolescent↗
PubMedDate not supplied

Isonymy structure of four Venezuelan states.

The isonymy structure of four Venezuelan States-Falcón, Mérida, Nueva Esparta and Yaracuy-was studied using the surnames of the Venezuelan register of electors updated in 1984. The surname distributions of 155 counties were obtained and, for each county, estimates of consanguinity due to random isonymy and Fisher's alpha were calculated. It was shown that for large sample sizes the inverse of Fisher's alpha is identical to the unbiased estimate of within-population random isonymy. A three-dimensional isometric surface plot was obtained for each State, based on the counties' random isonymy estimates. The highest estimates of random consanguinity were found in the States of Nueva Esparta and Mérida, while the lowest were found in Yaracuy. Other microdifferentiation indicators from the same data gave similar results, and an interpretation was attempted, based on the particular economic and geographic characteristics of each State. Four different genetic distances between all possible pairs of counties were calculated within States; geographic distance shows the highest correlations with random isonymy and Euclidean distance, with the exception of the State of Nueva Esparta, where there is no correlation between geographic distance and random isonymy. It was possible to group counties in clusters, from dendrograms based on Euclidean distance. Isonymy clustering was also consistent with socioeconomic and geographic characteristics of the counties.

Consanguinity↗
PubMedDate not supplied

Microevolution in Perugia: isonymy 1890-1990.

The distribution of surnames in the population of the Comune of Perugia, as it existed in the memory banks of the Municipality Computer in autumn 1991, was studied by age and place of birth. Fisher's alpha and Karlin-McGregor's v were estimated in the total population, in persons born before 1901, and in persons born in the nine decades thereafter, ending with the period 1981-1991, for immigrants and for natives of Perugia, respectively. The wealth of surnames was significantly higher in immigrants than in natives of Perugia, as detected by alpha, v and by the log-log regression of the corresponding distributions. Among residents born in Perugia, Fisher's alpha shows a minimum value during 1921-1930, explained as a consequence of the First World War. The relationship between all possible combinations of cohorts born in the 10 different decades was studied through the Euclidean distance and through Lasker's coefficient of relationship, and a significant correlation between the former and time was revealed, both in immigrants and in natives of Perugia. When compared with the Province of Ferrara, Perugia was far richer in surnames, as measured by Fisher's alpha, for the total population and for each of the 10 decades analysed. Recent immigration, measured by Karlin-McGregor's v, was significantly higher in Perugia until the 1960s, equal in both Provinces during the 1970s, and higher in Ferrara during the 1980s.

Adolescent↗