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Biomedical subjects

E Kobyliansky

Publications and source records attributed to E Kobyliansky.

At least 55 records · Page 3Linked to original sources
PubMed1991

Genetic affinities of Jewish populations.

Genetic relations between various Jewish (J) and non-Jewish (NJ) populations were assessed using two sets of data. The first set contained 12 pairs of matched J and NJ populations from Europe, the Middle East, and North Africa, for which 10 common polymorphic genetic systems (13 loci) were available. The second set included 22 polymorphic genetic systems (26 loci) with various numbers of populations (ranging from 21 to 51) for each system. Therefore, each system was studied separately. Nei's standard genetic distance (D) matrices obtained for these two sets of data were tested against design matrices specifying hypotheses concerning the affiliations of the tested populations. The tests against single designs were carried out by means of Mantel tests. Our results consistently show lower distances among J populations than with their NJ neighbors, most simply explained by the common origin of the former. Yet, there is evidence also of genetic similarity between J and corresponding NJ populations, suggesting reciprocal gene flow between these populations or convergent selection in a common environment. The results of our study also indicate that stochastic factors are likely to have played a role in masking the descent relationships of the J populations.

Gene Frequency↗
PubMed1990

Efficiency of cranial bilateral measurements in separating human populations.

A set of 31 nonconventional paired cranial measurements, as well as six conventional nonpaired measures, were taken on 266 skulls, representing two related populations: Bedouins of the Israeli Negev Desert and Bedouins of the Sinai. The data were subjected to univariate and discriminant analyses to determine the relative efficacy of paired vs. conventional measures in sorting individuals according to tribal and sex affiliation. It was found that paired measures have greater discriminatory power (87%) than conventional ones (47%) in terms of classifying individuals belonging to human isolates derived from a common ancestor and sharing similar environmental conditions. This greater discrimination attests to the value of the level of "developmental noise" (a measure provided by fluctuating asymmetry) in sorting human populations. Possible explanations are proffered for the above finding.

Adult↗
PubMed1990

The relative contribution of birth weight and gestational age to physical traits of newborn infants.

The present study establishes anthropometric standards for newborn infants, born between 26-41 weeks of gestational age. The measurement of 10 standard anthropometric traits was made within the first 72 hours of life in 224 preterm (26-36 weeks) and 190 term (37-41 weeks) infants. Multiple regression analysis was carried out for each of these anthropometric traits (dependent variables) on gestational age, birth weight and sex (independent variables). It was found that the prediction of several traits, namely, body length, body mass index, body surface area, interocular diameter, ear length and palm length, can be done solely via the information on birth weight; cephalic index is better predicted on the basis of gestational age, while for the prediction of such cranial traits as the circumference, length and breadth of head, both birth weight and gestational age are desirable.

Birth Weight↗
PubMed1989

Ethnic and family factors of some common diseases in early childhood.

The primary purpose of the present study was to examine the comparative incidence of some common diseases with unknown genetic components (e.g. newborn jaundice, urinary and respiratory tract infections) in infants of Israeli families of mixed and non-mixed ethnic origin. We also studied possible relationships between risk of these diseases and a number of anthropometric and demographic factors. Only the group of infants whose parents originated from North Africa and Middle East showed statistically significant differences: namely an increased level of total morbidity, of various comparisons of specific disease frequencies, and in total illness frequency, between infants from "mixed" and "non-mixed" families. In general, however, there was a positive correlation between frequency of healthy infants in "mixed" group and genetic distance between parents. Our findings also indicated a significant association between weight and head circumference of newborn infants respectively, and their illnesses, especially jaundice.

Africa, Northern↗
PubMed1988

Decreased developmental stability as assessed by fluctuating asymmetry of morphometric traits in preterm infants.

Fluctuating asymmetry (FA) of 8 morphometric traits was studied in 113 preterm infants (26-36 wk of gestation), 103 term infants (37-41 wk), and their respective parents. With 3 different measures of FA, the highest values were obtained from extremely preterm infants (26-29 wk), and the lowest from the group of term infants. The estimates of FA values among parents, particularly mothers, showed a similar, albeit less pronounced, trend. Multiple regression analysis of individual mean FA values, calculated in infants for the 8 studied bilateral traits, documented a significant inverse correlation with gestational age and with the health status of the infants and their mothers, as well as a positive correlation with the mothers' mean FA values.

Anthropometry↗
PubMed1988

Some biological and social factors of risk associated with the birth of pre-term infants.

The main purpose of the present study was to evaluate the effects of factors associated with spontaneous pre-term births so that the high risk woman could be identified before or at early stages of pregnancy. For this purpose, we have compared the measurements of 21 anthropometric traits and mean fluctuating asymmetry over 8 bilateral anthropometric traits, as well as age, occupation, education, previous obstetric history, complications during pregnancy, medicines received during and after pregnancy and some others in women who delivered babies of short (26-36 wk, n = 113 ind.) and normal gestational age (n = 103). Diseases and mean fluctuating asymmetry of eight morphological traits in the newborn infants themselves were also studied. Both univariate and multivariate analyses were carried out and these were in agreement, showing a highly significant increase in the morbidity rate (especially of respiratory diseases) among pre-term infants and in complications during pregnancy in their mothers. Among other variables associated with the current pre-term birth were previous spontaneous pre-term births, suggesting their special risk value. The estimate of the sib correlation in gestational age on the liability scale was about 0.63. Spearman and Pearson correlations in gestational age for siblings were 0.34 and 0.31, respectively.

Female↗
PubMed1987

Dermatoglyphic traits as possible markers of developmental processes in humans.

Here we provide data on the relationship in variability between common anthropometric characters (stature, interocular diameter, mesosternal chest circumference, bi-trochanteric diameter, and palm length) and dermatoglyphic traits in groups of young healthy individuals. Our working hypothesis was that quantitative variables of fluctuating asymmetry, diversity, and variability involving dermatoglyphic traits, will be higher in more homozygous groups than in heterozygous ones. It was found that individuals who were in the center (average +/- 0.67 SD) of the morphological trait distribution (and therefore perhaps more heterozygous at loci determining the aforementioned morphological traits), have reduced fluctuating asymmetry in their ridge counts (RC). These heterozygous individuals tended to have lower values of the RC-diversity-indices and the Shanon information-measures of discrete digital patterns. On the basis of the present results and a large body of literature data, the use of dermatoglyphic traits as "markers" of developmental processes are discussed.

Adolescent↗
PubMed1987

Sibling similarity in development of covariation among physical traits in early childhood.

We studied the sibling similarity in development of covariation among body size characters (body weight (W), body length (S) and head circumference (HC) in Tel Aviv infants from birth up to 2 years of age. We investigated the effects of parental geographic origin, profession, age, current residence, and of family size. Multiple regression analysis with "dummy" procedure established that none of these variables had any significant effect on the aforementioned anthropometric traits. The matrices of phenotypic and genetic correlations, based on sibling similarity data, among age-specific W, S, and HC (measured for 12 different ages) were subjected to principal component analysis in order to elucidate patterns over the age groups. The patterns of both analyses, phenotypic and genetic, were quite similar: one factor in each (first genetic and second phenotypic) had a high positive correlation with early, first 2-3 months of life, W, S, and HC. Three other extracted factors correlated strongly, each with late W, S, and HC, respectively. The results of additional principal component analyses of age-specific W, S, and HC matrices separately, indicate the possibility of existence of two genetic subsystems, the first determining early postnatal stages of human ontogeny, and the second, later phases of child development.

Body Height↗
PubMed1987

Directional dental asymmetry in South Sinai Bedouin isolates.

Dental casts of 242 Bedouin children were used to study directional asymmetry (DA). Results of Student's t-test pair comparison showed that for permanent dentition, 4 out of 24 DA measures were statistically significant whereas for deciduous dentition, 8 out of 20 measures were significant (p less than 0.05). The magnitude of DA was on the average 1% of the total size of the tooth. No preference regarding dimension (buccolingual, mesiodistal) or jaw (maxilla, mandible) was detected for the DA. PCA results demonstrated the independent nature of DA measures in the dentition.

Adolescent↗
PubMed1986

Anthropometric multivariate structure and dermatoglyphic peculiarities in biochemically and morphologically different heterozygous groups.

Multivariate analysis of the relationship between degree of heterozygosity at four blood group loci and the morphological variability in a human population was carried out. Additionally, the possibility that dermatoglyphic patterns correlate with biochemical and anthropometric variables was also investigated. A strong and significant increase in the frequency of morphologically multimodal individuals was observed, which paralleled the heterozygosity level. Discriminant analysis, by quantitative characters, of the closest pair of biochemically different samples yielded a satisfactory discrimination. Multiple correlations of each variable with all the others (18 traits), the communality of characters, the index of integration, and the Mahalanobis distances of the factor scores for each individual (all extracted from principal component analysis) were all indicative of the different multivariate structures of homo- and heterozygous individuals and thus supported the hypothesis that heterozygotes tend to cluster near the center of the joint multivariate distribution. The dermatoglyphic patterns showed a certain relationship with the morphological makeup of individuals. Correlations between biochemical heterozygosity at blood group loci and patterns of digital dermatoglyphics were rather irregular.

Adolescent↗
PubMed1986

Multivariate structure of human populations: sedentary versus migrants.

The rate change of gene frequency in a population subject to emigration obviously depends on differences in the effective reproductive size (and resulting random genetic drift effects) between emigrants and natives. An important additional force may be the different selection pressures of the original and the new environment into which the population penetrates. Discrete traits and monolocus systems have been studied in many natural populations of various species. However, knowledge about the migration influence on quantitative, i.e. polygenic, characters is very limited. The present study set out to answer the following biological questions: (1) Does migration induce changes in sets of phenotypic, genetic and environmental correlations? (2) If so, are these changes expressed in levels and/or structure of the correlation matrices? Data on 20 anthropometric traits in 305 Mexican families [129 families from Mexico (sedentary population) and 176 families living in Texas (migrant population)] were used for analysis. The curves of distribution and average values of phenotypic, genetic and environmental correlations remained unchanged between the two populations. However, qualitatively (i.e., as far as the agreement between matrix compositions is concerned), all three matrices changed significantly. The phenotypic correlations appear to be the most highly canalized, the correspondence between the two matrices being 62.1%. The environmental matrices had the highest variation, and although 26.3% of the correlations were in agreement, this was statistically nonsignificant. The most important finding in the present study was the relatively low correspondence between the two genetic matrices (35.6%). We suggest that these changes were provoked by preselection (i.e., by a nonrandom sample) of migrating individuals.

Anthropometry↗
PubMed1985

Lerner's concept of developmental homeostasis and the problem of heterozygosity level in natural populations.

In recent years adherents of the neutral mutation hypothesis have conducted a variety of statistical tests concerning the applicability of their theory to data of biochemical genetic polymorphism in natural populations. From the other side, the involvement of natural selection as a main evolutionary force responsible for the observed levels of polymorphism and heterozygosity have also been proposed in numerous field studies and theoretical considerations. However, none of these hypotheses completely and satisfactorily explains the collected data. We believe that one of the main causes of the discrepancy in theories is that the variability at each locus is considered independently in both of the above-mentioned approaches. Yet, it was suggested long ago, and now there is an increasing amount of evidence indicating cooperation between different loci which can influence the variability at each of them. Thus we think that the use of models considering the genome as a suit of independent genes is a priori expected to decrease the efficacy of the approximation. In the present review we attempt to draw attention to findings of interdependence of the variability of different characters and its possible limiting action on the growth of genetic diversity in natural populations. We do not try to give a universal explanation for the processes acting in populations and determining levels of heterozygosity. However, to our mind, the solution of the discussed question requires consideration of genes in their interactions.

Alleles↗