Variation of anthropometric traits in normal newborns]

Variation of the set of anthropometric traits was studied in 302 normal singleton newborns (174 boys, 128 girls). Birth order has a significant effect on birth weight, body length and circumference of head and breast. The number of minor deviations from development per newborn (stigma) is negatively correlated with body weight and size. The number of stigma is significantly higher in a group of newborns deviated in normal body proportions. The index of fluctuating asymmetry is negatively correlated with body weight and size.     

Addition to the article by Iu. E. Dubrova et al. "Influence of heterozygosity on the variation of anthropometric traits in newborns." Determination of intersample differences by covariation and correlation statistics]

Relationships between heterozygosity of 13 polymorphic loci and variation of the set of anthropometric traits were studied in 302 singleton newborns (174 boys, 128 girls). Statistically significant correlation between heterozygosity and all traits were not found. Variances of four traits--body weight, body length, circumference of head and breast measured by first principal component decrease with increase of heterozygosity in boys and girls. At the same time, variance of body proportions (second principal component) increase significantly in boys only. The highest values of correlation between four traits were found in the group of low heterozygous boys. The groups of newborns with different level of heterozygosity are characterized by different combinations of first principal component and the number of minor deviations from development (stigma). It is concluded from the whole set of data that newborn boys with the average level of heterozygosity have the highest level of viability.     

Spatial variation of anthropometric traits in Ireland.

To further elucidate the relationship between geography and genetics in Ireland, we considered variation in anthropometric traits of adult males by town using spatial autocorrelation methods. By describing and distinguishing significant patterns of anthropometric variation, we determined whether the anthropometric traits display a simple pattern of spatial variation, as predicted by the isolation by distance model, or other patterns of spatial variation. Several hypotheses were examined, including (1) whether there was spatial patterning of 20 anthropometric phenotypic distributions and 7 principal components of Irish males and (2) if there was, whether these phenotypic distributions could be explained by a simple isolation by distance model. The results of this study can be summarized by several key findings: (1) There is significant spatial patterning among towns, as detected in correlograms of 14 anthropometric traits and 2 principal component factor scores (values of Moran's I ranging from 0.7510 to -0.3616, p < or = 0.0071); (2) 4 spatial patterns were detected, including clinical patterns, long-distance differentiation, distance distinction, and regional patchiness. These results suggest several likely causes of the observed spatial patterns. First, in Ireland patterns of anthropometric variation could not be explained by a single spatial pattern (i.e., isolation by distance). Second, through an examination of the various combinations of statistical homogeneity or heterogeneity, spatial patterning or nonpatterning, and similarity or dissimilarity of spatial patterns, we conclude that several migrational events structured the genetic landscape of Ireland.     

Natural selection on anthropometric traits of Estonian girls

Natural selection is a key mechanism of evolution, which results from the differential reproduction of individuals due to differences in phenotype. We describe fecundity selection on 13 anthropometric traits in a sample of 4000–10,000 of Estonian girls, who were born between 1937 and 1962 and measured at around 13 years of age. Direct selection favoured shorter, slimmer and lighter girls with smaller heads, more masculine facial and body shapes and slower rates of sexual maturation. Selection was stabilizing for weight, body mass index and face roundness. Direct selection was absent on two markers of general health and viability – handgrip strength and vital lung capacity – although these traits experience negative indirect selection due to their association with educational attainment. Similarly, indirect selection, mediated by educational attainment, accounted for a significant portion of selection for girls with smaller heads, narrower faces, and higher shoulder/hip ratios. These traits are thus subject to gene-culture coevolution, in that selection on body dimensions arises via cultural and behavioural mechanisms.     

The influence of mother's active smoking during pregnancy on body mass index of newborns

Many investigations have noted bad influence of smoking during pregnancy. In the present article, the influence of mothers smoking during pregnancy on the body mass index (BMI), birth weight and birth length are examined. This retrospective research included 219 children: Group I: 109 children from rural area of east Slavonia (born in General Hospital-Vinkovci) and group II: 110 children from industrial area (born in Zagreb). The questioned subjects were divided into two groups depending on mothers smoking during pregnancy: newborns of mothers who didn't smoke during pregnancy (subgroup A) and newborns of mother who did smoke 10 or more cigarettes per day during pregnancy (subgroup B). Anthropometric parameters (BMI, birth length and birth weight) in newborns of non-smoking mothers were statistically higher (p < 0.05) than in newborns of smoking mothers. Moderate correlation between birth length and birth weight in newborns of non-smoking and smoking mothers from rural area and from non-smoking mothers in urban area was statistically significant, but correlation in the group in newborns of smoking mothers from Zagreb was not statistically significant. Results of this research show that smoking during pregnancy significantly influences the birth weight and birth length. Further investigation is needed, to investigate the lack of correlation between the birth length and birth weight in newborns of smoking mothers from industrial city.     

Genetic drift and anthropometric variation in Ireland

The effect of genetic drift on the genetic structure of seven Irish populations was investigated using anthropometric data collected during the 1890s on 259 adult males. These populations ranged in size from 769 to 3757, were relatively stable over time, and were located within 119 km of one another. Two populations are known to have experienced considerable English admixture. Data on ten anthropometric variables (three body measures and seven craniofacial measures) were adjusted for age and used to compute a relationship (R) matrix. The R matrix was converted into a distance measure and compared with a potential genetic drift distance measure, defined as (1/Ni + 1/Nj), where Ni and Nj are the effective population sizes of groups i and j (derivation of this formula is presented). Distances were rank-transformed, and the correlation between their pairwise elements was computed using matrix permutation methods to assess significance. Under the hypothesis that drift affects anthropometric variation, these correlations are expected to be positive. The correlation between anthropometric distance and potential genetic drift distance is 0.123, which is not significantly different from 0 (P = 0.368). When a multiple regression model is used to adjust for geographic distance and English admixture, the partial correlation (0.369) is significant (p = 0.021). As part of further analysis of the genetic structure of these populations, the same analyses were repeated using a distance matrix derived from surname frequencies. The correlation of surname distance and potential genetic drift distance is 0.164, which is not significant (p = 0.264). When the multiple regression model is applied, the correlation is 0.401, which is borderline significant (p = 0.055). These results show the influence of genetic drift, local migration, and admixture on Irish population structure.     

Influence of interfering stimuli on contingent negative variation]

The aim of this study was to examine the influence of interfering stimuli on subjects' C.N.V. With a labyrinthic stimulation before association S1-S2 and arithmetic calculation task between S1 and S2, the C.N.V. showed a statistically significant variation (P less than 0.025): it became prolonged after the response to S2. Provocation of a prolonged C.N.V. could be used as criterion to determine an individual threshold of stress.     

Assortative mating for anthropometric traits in parents of Punjabi twins

The marital correlations between 97 pairs of parents of Punjabi twins reveal positive phenotypic assortative mating for body traits while almost random mating with respect to cranio-facial traits. There is no evidence of any significant negative assortative mating for any of the 50 traits. The results have been compared with those from other world populations. The data contradict the earlier reported hypothesis that assortative mating is associated with lowered fertility.     

Family factors and somatic traits of newborns

The paper is focused on relationships between somatic traits of newborns and family factors. Data for 779 families and their offspirng born in hospitals of Bialystok and Zambrow were analyzed. Family factors were extracted based on a factor analysis of 23 family traits. Multiple regression analysis was used to find relationships between offspring traits and family factors. It has been found that the most important factor of the somatic development of the fetus is the body size of the mother and placenta weight (factor F5). The mother has a greater effect on the development of the child than the father does. Family culture (consciousness-F1) is an important factor during the prenatal devlopment, more important than socio-economic conditions of the family (F3). Also the effect of father's morbidity (factor F8) is relatively high, almost as high as the effect of mother's morbidity (factor F6), more important than the body build of the father (factor F7). Age of the parents and the number of earlier pregnancies (factor F2) have the lowest effect on somatic traits of newborns. Blood pressure of the mother (factor F4) has relatively little effect on the development of somatic traits in newborns. The traits most affected by family factors include frontal breadth, body weight, chest size, and hip breadth.     

Familial resemblance for anthropometric traits in dizygotic twins and siblings

Familial resemblance for fifty anthropometric traits was studied on a sample of 45 MZ, 101 DZ twin pairs and their 125 singleton siblings. Intraclass correlation coefficients were significant for all the traits. However, resemblance within DZ twin pairs was significantly greater than within sibs for 22 variables, showing that the former had a more correlated environment than the latter. The study also showed that head and facial traits were relatively more stable to the environmental factors than the body traits and hence more suitable for cross-cultural comparisons. The study listed measures of girth and skinfold, thickness as the most labile traits.     

Direct and indirect causal effects of heterozygosity on fitness-related traits in Alpine ibex

Heterozygosity–fitness correlations (HFCs) are a useful tool to investigate the effects of inbreeding in wild populations, but are not informative in distinguishing between direct and indirect effects of heterozygosity on fitness-related traits. We tested HFCs in male Alpine ibex (Capra ibex) in a free-ranging population (which suffered a severe bottleneck at the end of the eighteenth century) and used confirmatory path analysis to disentangle the causal relationships between heterozygosity and fitness-related traits. We tested HFCs in 149 male individuals born between 1985 and 2009. We found that standardized multi-locus heterozygosity (MLH), calculated from 37 microsatellite loci, was related to body mass and horn growth, which are known to be important fitness-related traits, and to faecal egg counts (FECs) of nematode eggs, a proxy of parasite resistance. Then, using confirmatory path analysis, we were able to show that the effect of MLH on horn growth was not direct but mediated by body mass and FEC. HFCs do not necessarily imply direct genetic effects on fitness-related traits, which instead can be mediated by other traits in complex and unexpected ways.     

Inheritance of isozyme variation and heterozygosity in Pinus ponderosa

Techniques are presented to detect 23 isozyme loci in the long-lived perennial plant, ponderosa pine. Meiotically derived megagametophyte from seeds is used to examine directly the segregation of allelic variants. Approximately seven seeds were initially examined for 12 enzymes from each of 47 trees from ten stands throughout the northern Rocky Mountain region. Additional seeds were also examined from selected families to confirm the inheritance of observed electrophoretic variants at 13 polymorphic loci and to estimate linkage relationships. Significant nonrandom segregation was consistently detected for three pairs of loci: ADH-1: AAT-2, ADH-1: PGI-1, and LAP-2: 6PG-1. Preliminary estimates of population parameters reveal a relatively high average heterozygosity (H=0.123). This is partitioned into a high amount of genetic variation within local stands, with only approximately 12% of the total heterozygosity resulting from genic differences between stands.Funds for this study were made available under the McIntire-Stennis program of the Forest, Range, and Conservation Experiment Station of the School of Forestry, University of Montana.     

The population growth consequences of variation in individual heterozygosity

Heterozygosity has been associated with components of fitness in numerous studies across a wide range of taxa. Because heterozygosity is associated with individual performance it is also expected to be associated with population dynamics. However, investigations into the association between heterozygosity and population dynamics have been rare because of difficulties in linking evolutionary and ecological processes. The choice of heterozygosity measure is a further issue confounding such studies as it can be biased by individual differences in the frequencies of the alleles studied, the number of alleles at each locus as well as the total number of loci typed. In this study, we first examine the differences between the principal metrics used to calculate heterozygosity using long-term data from a marked population of Soay sheep (Ovis aries). Next, by means of statistical transformation of the homozygosity weighted by loci index, we determine how heterozygosity contributes to population growth in Soay sheep by modelling individual contributions to population growth (p(t(i))) as a function of several covariates, including sex, weight and faecal egg count--a surrogate of parasitic nematode burden in the gut. We demonstrate that although heterozygosity is associated with some components of fitness, most notably adult male reproductive success, in general it is only weakly associated with population growth.     

Lack of effect of maternal body mass index on anthropometric characteristics of newborns in twin gestations

We examined the correlation between maternal prepregnancy body mass index (BMI) and newborn weight, length, BMI, and gestational order, in singleton and twin births. The sample comprised 381 mothers of multiple babies (562 twins), and 7979 singleton pregnancies, used as controls. The Mann-Whitney non-parametric test was used to compare the values between the two groups, and the Spearman's correlation test (rS) was applied to the quantitative variables. A significant positive correlation was found with singleton baby variables: the higher the maternal BMI, the higher the newborn's BMI, weight, length, and gestational order. However, no significant correlation was found between maternal BMI and any of these variables in twins. Maternal weight gain, in the twin group, showed a significant positive correlation with the newborn gestational order (rS = 0.154; P = 0.002), weight (rS = 0.493; P < 0.001), length (rS = 0.469; P < 0.001), and BMI (rS = 0.418; P < 0.001). In singletons, the correlation was positive with all the variables, except for the gestational order. The newborn BMI was significantly higher in twins born by C-section than those born by vaginal birth (Z = -4.974; P < 0.001). Mothers of singletons delivered by C-section had a significantly higher BMI than those of singletons born by vaginal birth (Z = -1.642; P < 0.001); however, no significant differences were observed in mothers of twins. Prepregnancy maternal BMI in twin births would not be predictive of newborns weight, length and BMI in this population. Maternal weight gain during pregnancy proved to be the most adequate for predicting the weight, length and BMI of twins delivered by C-section.     

Influence of postconceptual age on the electromyographic characteristics in newborns

The purpose of the study was to investigate the neuromuscular state in the preterm infants using surface electromyography (EMG). Ten preterm (gestational age, 31–32 weeks) and ten term infants (gestational age, 38–39 weeks) participated in the study in the second, fourth and sixth postnatal weeks. Linear and novel nonlinear parameters were used for the treatment of the interference EMG (iEMG) in four muscles (mm. bic. br. dext., trie. br. dext, tib. ant. sin., and gastr. sin.). In the preterm infants aged 33–37 weeks, both linear and nonlinear iEMG parameters were significantly lower in comparison to the term infants. Thus, the iEMG of the preterm infants was characterized by a more primitive time-domain structure and lower amplitude and spectrum frequency. In addition, unlike in term newborns, the lifetime dynamics of the iEMG parameters in the preterm infants was retarded. Thus, the motor system of a preterm infant is likely to be less prepared for postnatal life due to the shorter stay in utero. Nonetheless, the iEMG of the preterm infants may be characterized as more complex in comparison to the term newborns of the same postconceptual age. This may be attributed to the new postnatal sensory stimuli.     

Population-specific variation in haplotype composition and heterozygosity at the POLB locus

DNA polymerase beta plays a central role in base excision repair (BER), which removes large numbers of endogenous DNA lesions from each cell on a daily basis. Little is currently known about germline polymorphisms within the POLB locus, making it difficult to study the association of variants at this locus with human diseases such as cancer. Yet, approximately thirty percent of human tumor types show variants of DNA polymerase beta. We have assessed the global frequency distributions of coding and common non-coding SNPs in and flanking the POLB gene for a total of 14 sites typed in approximately 2400 individuals from anthropologically defined human populations worldwide. We have found a marked difference between haplotype frequencies in African populations and in non-African populations.     

Racial differences in anthropometric traits in school children of Bahia,Brazil

Two thousand four hundred and forty-four Brazilian school children were classified as Light, Medium and Dark according to a subjective judgment of the proportion of Negro admixture, and studied for weight, height, span and upper-segment/lower-segment (US/LS) ratio. The mean US/LS ratio decreases significantly as the proportion of Negro admixture increases giving an intermediate value for those children belonging to the Medium group for race.