Familial resemblance for anthropometrical traits in a Bulgarian population

Genetic influences on body and craniofacial morphology have been studied on a sample of 251 fathers and 251 mothers and their 502 children over 15 years in 251 urban Bulgarian families. Midparent-offspring correlation coefficients are consistently higher than those from single parent-offspring. However, these values are lower than those expected under exclusive polygenic model, indicating considerable environmental influences. Dominance could be present for 3 body traits and for 2 cranio-facial traits. The hypothesis of higher maternal influence could be proposed for biacromial diameter and of higher paternal influence for head height, nose height and for ear height and breadth. The pattern of the different parent-offspring correlations (father-daugther, fatherson, mother-daughter, mother-son) is not compatible with a hypothesis of X-linkage heredity.     

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.     

Familial resemblance in maximal heart rate, blood lactate and aerobic power

There are considerable interindividual differences in maximal oxygen uptake per kilogram of body weight (VO2 max/kg), maximal heart rate (max HR) and maximal blood lactate (max blood La) measured during a progressive exercise test. The aim of the study was to quantify the familial relationships for these variables. Parents and children of 38 families of French-Canadian descent were submitted to a modified Balke treadmill test. VO2 max/kg and max HR were the highest values reached during the test for 1 min. Max blood La was obtained from a blood sample taken 2 min after the test. The effects of age and sex were significant for max blood La and VO2 max/kg in each generation. Scores were thus adjusted through multiple regression procedures (age + sex + age X sex + age2), yielding residuals which were submitted to further analysis. Intraclass correlations (ri) were significant in pairs of sibs for max blood La and max HR, i.e. 0.28 (p less than 0.01) and 0.43 (p less than 0.05), respectively. For VO2 max/kg, pairs of spouses and sibs were about similarly correlated (ri = 0.20 and 0.15; p less than 0.05). Data suggested that children were more related to their mother than to their father for VO2 max/kg, VO2 max/kg of fat-free weight, and particularly for max HR. It was concluded that familial resemblance and heritability estimates for maximal aerobic power, max HR and max blood La were quite low and generally nonsignificant. Correlations between biological sibs were, however, consistently significant for max HR and max blood La. The suggestion of a maternal effect in maximal aerobic power should be further investigated.     

Basal serum immunoglobulin levels

Two congenic strains of mice were identified that differ in their serum immunoglobulin levels. The strains were crossed, the F₁ progeny were intercrossed, and the serum immunoglobulin levels of the F₁ and F₂ progeny were analyzed. The F₁ mice have serum immunoglobulin levels like that of the high parent, and the low-immunoglobulin phenotype segregates in the F₂ population. Six other inbred strains of mice were also characterized for basal serum levels of five classes of immunoglobulin.     

Familial resemblance of body composition,physical activity,and resting metabolic rate in pre-school children

Background:

Although parental obesity is a well-established predisposing factor for the development of obesity, associations between regional body compositions, resting metabolic rates (RMR), and physical activity (PA) of parents and their pre-school children remain unknown. The objective of this study was to investigate parent-child correlations for total and regional body compositions, resting energy expenditures, and physical activity.

Methods:

Participants were 89 children aged 2-6 years and their parents, consisting of 61 families. Resting metabolic rate was assessed using indirect calorimetry. Total and regional body compositions were measured by both dual energy X-ray absorptiometry (DXA) and deuterium dilution. Physical activity was assessed by an accelerometer.

Results:

There was a significant parent-offspring regression for total fat free mass (FFM) between children and their mothers (P=0.02), fathers (P=0.02), and mid-parent (average of father and mother value) (P=0.002) when measured by DXA. The same was true for fat mass (FM) between children and mothers (P<0.01), fathers (P=0.02), and mid-parent (P=0.001). There was no significant association between children and parents for physical activity during the entire week, weekend, weekdays, and different parts of days, except for morning activity, which was positively related to the mothers’ morning activities (P<0.01) and mid-parent (P=0.009). No association was found between RMR of children and parents before and after correction for FFM and FM.

Conclusion:

These data suggest a familial resemblance for total body composition between children and their parents. Our data showed no familial resemblance for PA and RMR between children and their parents. Key Words: Obesity, Familial resemblance, Children, Resting metabolic rate, Physical activity     

Residual family resemblance for PTC taste sensitivity

Summary Complex segregation analysis reveals no evidence for incomplete dominance, polygenic variation, or an effect of family environment on PTC sensitivity. Estimates of gene frequency and displacement from a phenotypic trichotomy agree closely with conventional values for the dichotomy of tasters vs. nontasters.     

Familial resemblances in blood leukocyte DNA methylation levels

Epigenetic factors such as DNA methylation are DNA alterations affecting gene expression that can convey environmental information through generations. Only a few studies have demonstrated epigenetic inheritance in humans. Our objective is to quantify genetic and common environmental determinants of familial resemblances in DNA methylation levels, using a family based sample. DNA methylation was measured in 48 French Canadians from 16 families as part of the GENERATION Study. We used the Illumina HumanMethylation450 BeadChip array to measure DNA methylation levels in blood leukocytes on 485,577 CpG sites. Heritability was assessed using the variance components method implemented in the QTDT software, which partitions the variance into polygenic (G), common environmental (C), and non-shared environmental (E) effects. We computed maximal heritability, genetic heritability, and common environmental effect for all probes (12.7%, 8.2%, and 4.5%, respectively) and for statistically significant probes (81.8%, 26.9%, and 54.9%, respectively). Higher maximal heritability was observed in the Major Histocompatibility Complex region on chromosome 6. In conclusion, familial resemblances in DNA methylation levels are mainly attributable to genetic factors when considering the average across the genome, but common environmental effect plays an important role when considering statistically significant probes. Further epigenome-wide studies on larger samples combined with genome-wide genotyping studies are needed to better understand the underlying mechanisms of DNA methylation heritability.     

Commingling in the distributions of immunoglobulin levels

Commingling in the distributions of five immunoglobulins from a Canadian sample of 810 Caucasians and IgE from a US sample of 935 Caucasians was investigated. For both the Canadian and US samples significant commingling was found in the child's but not the adult's IgE distribution. Contrary to expectations based upon the major gene hypothesis for IgM, we found no evidence for commingling in the IgM distribution. Finally, the distributions of IgA, IgD and IgG all evidenced significant commingling that may be the result of a single gene effect or the operation of a discrete environmental effect.     

Facial resemblance enhances trust

Organisms are expected to be sensitive to cues of genetic relatedness when making decisions about social behaviour. Relatedness can be assessed in several ways, one of which is phenotype matching: the assessment of similarity between others' traits and either one's own traits or those of known relatives. One candidate cue of relatedness in humans is facial resemblance. Here, I report the effects of an experimental manipulation of facial resemblance in a two-person sequential trust game. Subjects were shown faces of ostensible playing partners manipulated to resemble either themselves or an unknown person. Resemblance to the subject's own face raised the incidence of trusting a partner, but had no effect on the incidence of selfish betrayals of the partner's trust. Control subjects playing with identical pictures failed to show such an effect. In a second experiment, resemblance of the playing partner to a familiar (famous) person had no effect on either trusting or betrayals of trust.     

Reduction of saliva immunoglobulin levels by swim training

Saliva immunoglobulin A (IgA) and cortisol levels were measured in 21 male members of a major midwestern swim team. Saliva samples were collected before and after training sessions four times during the fall season; the training intensity was light, moderate, heavy and during the taper period before a major competitive meet. Saliva IgA levels were decreased after each training session, reaching statistical significance with the moderate training intensity. Over the 3-month training period the pre-session and post-session IgA levels both decreased significantly during the heavy and taper training intensities later in the fall season. Cortisol levels were significantly elevated only after the heavy-intensity training session. The Profile of Mood States (POMS) was used to assess the swimmers' overall mood on each test day. No significant correlations were found between the global POMS score and IgA or cortisol. Also, cortisol and IgA were not significantly correlated except after the light training session. Results from this study indicate that acute bouts of exercise can reduce salivary IgA levels and that chronic exercise of high intensity can reduce the resting levels of IgA. These changes may render the athletes more vulnerable to respiratory infections after exercise and even at rest during the later stages of the competitive season.     

Serum immunoglobulin levels following allogeneic bone marrow transplantation

In order to study the posttransplant evolution of serum immunoglobulin levels, we measured serum IgG, IgA and IgM levels in 50 recipients of allogeneic bone marrow before transplantation and at different intervals thereafter (days 39, 120, 365 and 730). IgG and IgM levels were depressed for 1 year and IgA levels for 2 years posttransplant. Immunoglobulin deficiency was more severe and prolonged in patients with graft versus-host-disease. Hypogammaglobulinemia may contribute to the frequent infections observed in these patients, especially those with chronic graft-versus-host disease.     

Family resemblance for components of craniofacial size and shape

Path analysis is used to analyze family resemblance for eight principal components extracted from 30 anthropometric measurements of the craniofacial complex. Based on likelihood ratio tests, the null hypothesis of no assortative mating is rejected for the nasal height component. The null hypothesis of no common sibling environmental effect is rejected for the cranial size, craniofacial breadth, and nasal height components. Finally, the hypothesis that transmission from both mother and father is equal to 1/2, consistent with simple autosomal polygenic inheritance, is rejected for components corresponding to craniofacial breadth and upper facial height, thus implicating some effect of familial environment. Transmissibility is higher for components related to cranial size and facial height than for those related to facial breadth or ear dimensions.     

On choosing a resemblance measure for non-linear predictive ordination

The development of non-linear ordination techniques has stemmed in part from work suggesting that species behave non-linearly to changing environmental factors or gradients. Developments in this area can be seen in two related phases: new algorithms, and the incorporation of new resemblance measures. Emphasis in this paper is placed on resemblance measures incorporated into a method of multi-dimensional scaling. The results show that a resemblance measure which reflects the non-linearities of the data can produce significant improvement in ordination, if the standardizations have not been too ‘severe’.     

Familial resemblance of blood pressure with residual household environmental effects in consanguineous and nonconsanguineous families from Andhra Pradesh, India.

Familial aggregation of blood pressure (BP), both systolic (SBP) and diastolic (DBP), was examined in consanguineous and nonconsanguineous families from southern India. Path analysis of BP suggests inbreeding effects, with the genetic variance for SBP being lower in the sample that included inbred families. Specifically, genetic heritability for SBP was 38% in the nonconsanguineous sample but only 23% in the combined sample. Genetic heritability for DBP (30%) did not vary by sample, nor were sample differences in cultural heritability detected for either SBP (over 35%) or DBP (about 18%). These findings are remarkably similar to those in a French-Canadian population of Quebec; both reports found a considerably larger effect of the home environment on BP than previous studies.     

Relationship between immunoglobulin levels and extremes of solar activity

The possible relationship between epidemics and extremes of solar activity has been discussed previously. The purpose of the present study was to verify whether differences in the levels of immunoglobulins (IgA, IgG, IgM) could be noted at the highest (July 1989) and lowest (September 1986) points of the last (21st) and present (22nd) 11-year solar cycle. The work was divided into a 1-month study (covering the month of minimal or maximal solar activity), a 3-month study (1 month before and after the month of minimal or maximal solar activity) and a 5-month study (2 months before and after the month of minimal or maximal solar activity). A trend of a drop-off for all three immunoglobulins was seen on the far side of the maximal point of the solar cycle. Statistical significance was achieved in the 5-month study for IgM (P=0.04), and a strong trend was shown for IgG (P=0.07). Differences between the sexes were also noted.