Heritability of 2D:4D finger length ratio

A Chuvashian population-based sample included 802 males and 738 females (mean age 46.98±17.10 and 48.65±16.62 years, correspondingly). Age, basic demographics, anthropometric data, reproductive indices, and x-rays of both hands were collected. Results and discussion. Familial correlations of FLR traits showed no significant correlation for spouses, however, parent-offspring (0.15-0.28, p<0.001) and sibling correlations (0.13-0.38, p<0.009) were found significant. Heritability (H2) of visual classification of FLR was 0.36 for the left and 0.28 for the right hand; finger ratio was 0.55 and 0.66, respectively; the ray ratio was 0.49 and 0.59, respectively, thus indicating the existence of a clear familial aggregation of FLR variation in the Chuvashian pedigrees, which cannot be explained by pure common environmental effects. Conclusion. Results of our study suggest the familial aggregations of finger ratio variation (for all traits) in Chuvashian pedigrees. Further research should focus on the biological mechanisms of the relationship between FLR and aging.

Sibling Similarity in Education Across and Within Societies

The extent to which siblings resemble each other measures the omnibus impact of family background on life chances. We study sibling similarity in cognitive skills, school grades, and educational attainment in Finland, Germany, Norway, Sweden, the United Kingdom, and the United States. We also compare sibling similarity by parental education and occupation within these societies. The comparison of sibling correlations across and within societies allows us to characterize the omnibus impact of family background on education across social landscapes. Across countries, we find larger population-level differences in sibling similarity in educational attainment than in cognitive skills and school grades. In general, sibling similarity in education varies less across countries than sibling similarity in earnings. Compared with Scandinavian countries, the United States shows more sibling similarity in cognitive skills and educational attainment but less sibling similarity in school grades. We find that socioeconomic differences in sibling similarity vary across parental resources, countries, and measures of educational success. Sweden and the United States show greater sibling similarity in educational attainment in families with a highly educated father, and Finland and Norway show greater sibling similarity in educational attainment in families with a low-educated father. We discuss the implications of our results for theories about the impact of institutions and income inequality on educational inequality and the mechanisms that underlie such inequality.

Sibling correlation in risk attitudes: evidence from Burkina Faso

This study uses sibling correlation to provide novel descriptive evidence of parental and household characteristics on three different risk domains collected in a nationally representative survey from Burkina Faso. The sibling correlations are between 0.51 and 0.83. The correlations are higher in the general risk domain compared to risk taking in financial matters and traffic. Moreover, the sibling correlation is higher for sisters than brothers. We also explore which factors might drive these correlations; parents’ risk attitudes appears to play a role in explaining these correlations, whereas socioeconomic outcomes, family structure, parental health and residential zone seems to have only a limited contribution. We also find that gender seems to be important in explaining the variation in sibling correlations. Mother’s appear to have a stronger contribution on daughters than their sons correlation, whereas father’s help to explain their sons correlation.

Family, Community and Long-Term Socioeconomic Inequality: Evidence from Siblings and Youth Peers

Using administrative data for the population of Danish men and women, we develop an empirical model which accounts for the joint earnings dynamics of siblings and youth community peers. We provide the first decomposition of the sibling correlation of permanent earnings into family and community effects allowing for life cycle dynamics and extending the analysis to consider other outcomes. We find that family is the most important factor influencing sibling correlations of earnings, education and unemployment. Community background matters for shaping the sibling correlation of earnings and unemployment early in the working life, but its importance quickly diminishes.

Social Origin and Parental and Offspring Union Dissolution: Cues from Sibling Correlations

This paper estimates the size of the effect of parental union dissolution on offspring union dissolution, as a share of the sum of all social origin factors. A large literature has documented a positive correlation between divorce and separation among parents and their children. Parental union dissolution is one out of several aspects of social origin that is associated with union dissolution. It is difficult to contrast the relative impact of parental union dissolution to other aspects of social origin because many apects of social origin are unobservable. Swedish administrative data for the 1960 to 1965 birth cohorts that cover the individuals’ life events until 2018 is used to estimate sibling correlations in divorce and childbearing union dissolution, adjusting for parental union dissolution. The variance in union dissolution attributable to factors shared by siblings ranged from 6% to 13%. Parental union dissolution and factors associated with parental union dissolution explained between 15% and 28% of this variance. Sister correlations are greater than brother correlations, and sibling correlations of childbearing union dissolution are higher than sibling correlations of divorce. It is pertinent to estimate the total effect of all social background factors on offspring union dissolution. It is likewise of interest to specify the share of all social background effects that are constituted by factors caused by or correlated specifically with parental union dissolution. Sibling correlations can be a useful tool for quantifying these relationships.

The End of Dominance? Evaluating Measures of Socio-Economic Background in Stratification Research

We analyse how to best combine information on both parents’ socio-economic status (SES) in intergenerational research. This can be done by utilizing separate measures for each parent, taking averages over parents, modelling interactions, or only using the highest value across parents—the latter commonly referred to as the dominance approach. Our brief literature review suggests that (i) the dominance tradition is widespread, although seldom theoretically or empirically justified and (ii) parental interactive models are not widely used. We assess how much of the sibling correlations in continuous measures of education, occupation, and earnings that are explained by parents’ SES in the same dimensions using the different operationalizations. The dominance approach performs poorer than other models of parental SES. For the total contribution of socio-economic background, we find a bias of about 4–6 per cent for children’s education and occupational outcomes compared with other approaches. We also conduct a separate evaluation of nominal EGP social class operationalizations and find that the dominance approach is the most suboptimal choice compared with the alternatives. In conclusion, parental averages are preferred over dominance, as an attractive and parsimonious one variable alternative, although the highest explanatory power is attributed to models using two parental measures and an interaction term.

The pattern of educational inequality - The contribution of family background on levels of education over time and across four countries

This article analyses the pattern of inequality across levels of education and its evolution over time from a cross-national comparative perspective. We employ a previously disregarded approach of sibling correlations to measure how the contribution of the total family background differs across achieved levels of education. We compare successive birth cohorts in Finland, Sweden, Germany, and the U.S. between 1990 and 2015. We further analyze the extent to which the total contribution of parental background is accounted for by observed parental education. Our results indicate a pattern in which sibling similarity is strongest in the lowest and the highest levels of education in all studied countries. Changes over time were more pronounced in the Nordics and in educational levels other than the lowest. Observed parental education played a less notable role than expected, indicating that using only parental education ignores a substantial portion of the total influence of family background.

Developmental MRI markers cosegregate juvenile patients with myoclonic epilepsy and their healthy siblings

ObjectiveMRI studies of genetic generalized epilepsies have mainly described group-level changes between patients and healthy controls. To determine the endophenotypic potential of structural MRI in juvenile myoclonic epilepsy (JME), we examined MRI-based cortical morphologic markers in patients and their healthy siblings.MethodsIn this prospective, cross-sectional study, we obtained 3T MRI in patients with JME, siblings, and controls. We mapped sulco-gyral complexity and surface area, morphologic markers of brain development, and cortical thickness. Furthermore, we calculated mean geodesic distance, a surrogate marker of cortico-cortical connectivity.ResultsCompared to controls, patients and siblings showed increased folding complexity and surface area in prefrontal and cingulate cortices. In these regions, they also displayed abnormally increased geodesic distance, suggesting network isolation and decreased efficiency, with strongest effects for limbic, fronto-parietal, and dorsal-attention networks. In areas of findings overlap, we observed strong patient–sibling correlations. Conversely, neocortical thinning was present in patients only and related to disease duration. Patients showed subtle impairment in mental flexibility, a frontal lobe function test, as well as deficits in naming and design learning. Siblings' performance fell between patients and controls.ConclusionMRI markers of brain development and connectivity are likely heritable and may thus serve as endophenotypes. The topography of morphologic anomalies and their abnormal structural network integration likely explains cognitive impairments in patients with JME and their siblings. By contrast, cortical atrophy likely represents a marker of disease.