Search

The complex interplay between genetics, culture, and environment forms an individual’s biology, influencing their behavior, choices, and health. However, to what extent information derived from this intertwined network could be quantitatively summarized to provide a glance at an individual’s lifestyle is difficult to say. Here, we focused on dietary preferences as cultural proxies and genome-wide data of 543 individuals from six historical Silk Road countries: Georgia, Armenia, Azerbaijan, Uzbekistan, Kazakhstan, and Tajikistan. These lands favored the dispersal of innovations, foods, and DNA halfway across Eurasia, thus representing an ideal subject to explore interactions of cultural factors and genetic ancestry. We used discriminant analysis of principal components to infer cultural clusters, where mixed memberships are allowed. Five different clusters emerged. Of these, clusters 1 and 3, driven by aversion to pork and alcoholic beverages, mirrored genetic admixture patterns with the exception of Azerbaijan, which shares preferences supported by Islamic culture with Eastern countries. Cluster 3 was driven by protein-rich foods, whose preference was significantly related to steppe pastoralist ancestry. Sex and age were secondary clustering factors, with clusters formed by male and young individuals being related to alcohol preference and a reduced liking for vegetables. The soft clustering approach enabled us to model and summarize the individual’s dietary information in short and informative vectors, which show meaningful interaction with other nondietary attributes of the studied individuals. Encoding other cultural variables would help summarize an individual’s culture quantitatively, thus ultimately supporting its inclusion as a covariate in future association studies. [ABSTRACT FROM AUTHOR]

Objective: Age related hearing loss (ARHL) or presbyacusis is a complex condition caused by an interaction between environmental and genetic factors and is the most prevalent sensory impairment in the elderly. To date, only few environmental/lifestyle risk factors have been found. Research into risk factors underlying ARHL is increasingly urgent as populations grow older. Here, we investigate the relationship between ARHL and educational/occupational factors in a large cohort of people from isolated villages in Italy, Crimea region, Caucasus and Central Asia. Methods: Two thousand and sixty-eight people (aged 40-95 years) were recruited and analysed. Education was classified at five levels: no education, elementary, secondary, high school and university. Cases and controls were defined after a detailed evaluation of the hearing phenotype. Data were analysed using a mixed-effects logistic regression. Results: A statistically significant association between ARHL and education was detected. People with no education showed a higher association with the condition than people with a higher education ( p < 0.001). Explanations could be many, including individual jobs. A strong correlation (φ > 0.45) between occupation and level of education was also found. Conclusion: Present findings provide a better knowledge of environment/lifestyle factors related to ARHL and might help in defining new preventive strategies for aging people. [ABSTRACT FROM AUTHOR]

Taste is one of the main factors determining food choices. Differences in PROP bitter taste perception have been implicated in individual differences in food preferences and selection. The present study examined associations between, PROP phenotypes, self-reported food liking and TAS2R38 polymorphisms, the major gene implicated in PROP bitterness, in six different populations of the Caucasus and Central Asia, located along the ancient Silk Road. Differences in the distribution of PROP phenotypes across populations were detected, with a higher frequency of super tasters in Tajikistan (31.3%) and Armenia (39.0%) and a higher frequency of non tasters in Georgia (50.9%). While no relationships were observed between PROP phenotypes and food liking using standard statistical tests, we used an approach based on comparison of distance matrices derived from these data. The first matrix compared the food liking ratings of each population to all others pairwise using the Kruskal-Wallis test (at p<0.00063), and the second one compared the distribution of PROP phenotypes across all populations in a similar manner calculating the chi-square statistic as a distance measure. A strong correlation between the two matrices was found (Mantel test: r = 0.67, p-value = 0.03), suggesting that the pattern of food liking across populations was closely related to the distribution of PROP phenotypes. This same relationship was not observed when TAS2R38 genotypes were substituted for PROP phenotypes in this analysis. Our data suggest that a population-based approach utilizing distance matrices is a useful technique for detecting PROP-related differences in food liking and can be applied to other taste phenotypes.