By: AVIK RAY, SOHELA SOBNAM, ASHISH MUKHOPADHYAY, SUBIR BISWAS, MITHU BHADRA
In the present study, fluctuating asymmetry (FA) in digits, height, and BMI were selected as markers of developmental stress. The objective of this study was to examine the association or correlation between these indicators and the digit ratio (2D:4D) and to ascertain whether the digit ratio can effectively predict such stress markers. A random sample of 254 Rava males was selected from different blocks in the Alipurduar district of West Bengal, India. Initially, substantial asymmetries (at p<0.05) among all bilateral traits were measured. Subsequently, a correlation analysis was conducted among all variables, and regression models were developed to predict a composite fluctuating asymmetry index (CFAI). The CFAI was formulated based on asymmetries of all digits and height from significant predictors. Chi-square tests with Bonferroni post-hoc correction were also performed to explore any association between categories of CFAI and digit ratio designed through quartile classification. Ordinal logistic regression was then employed to predict the probabilities of category membership of CFAI from categories of 2D:4D. A subsequent analysis revealed that among the digits, only the second, third, and fifth digit ratios exhibited statistically significant asymmetry from right to left. The present study found a positive correlation between CFAI and the digit ratios of both hands, as well as a negative correlation with height, at p < 0.05 and p < 0.01, respectively. Furthermore, the right 2D:4D ratio has been demonstrated to outperform the left 2D:4D ratio in its capacity to predict fluctuating asymmetry. It is noteworthy that both ratios exhibit a curvilinear relationship with fluctuating asymmetry. Although further research is necessary to comprehensively elucidate the relationship between digit ratio and developmental instability, the FA can be utilized as a proxy.
