Exploring the variation association between four head traits

Abstract

This research work presents a comprehensive overview of four traits related to the head, with the aim of assessing the statistical phenotypic association among them. The traits examined in this study encompass earlobe type, tongue rugosity, cleft chin and tongue rolling. The primary objective was to investigate the potential associations between these traits and understand their interrelationships. The study focused on examining specific traits in a diverse group of 7431 unrelated individuals, where the genders were almost evenly distributed. To facilitate a comprehensive analysis, three distinct groups were created for each characteristic, comprising the total population, as well as male and female subsets. The selection of subjects was carefully done to ensure a fair representation across different geographical regions within Bosnia and Herzegovina, thereby accurately reflecting the nation's national and ethnic diversity. The association among these traits was assessed for statistical significance using the Chi-squared test, with Fisher's exact test used as a supplementary method to examine the connection between each pair of observed traits. Additionally, the Chi-squared test was applied to examine gender-based differences in the frequencies of the phenotypic characteristics of the head. Following traits were shown to have a statistically significant association: tongue rugosity - tongue rolling, tongue rugosity – earlobe type, cleft chin – earlobe type, cleft chin – tongue rolling and earlobe type – tongue rolling. Investigation into the variations in the frequencies of observed phenotypic traits of the head, with respect to gender, revealed statistically significant results for every trait examined.