Novel application of the ‘Hardy-Weinberg equilibrium’ in the analysis of cusp patterning phenotype in Gujarati Population

Abstract

The non-metric characteristics like the tooth shape, number of cusps and other structural features contribute for the forensic and anthropological investigations and in establishing the population inter-relationships. The mandibular 2nd premolar and the maxillary 2nd molars often show variations in their occlusal morphology. The Hardy-Weinberg equilibrium is applied in a novel way to determine the cusp phenotype in these two teeth in a representative sample from Gujarati population. The dental stone models of 295 students of dental college in the age range of 19–23 years were used for this study. The two-cusped second premolar was present in around 60% the subjects on both the right and left side. There is no significant difference in the distribution of the number of cusps in both the right and left second premolars between male and female subjects. There was a significant difference in the distribution of the number of cusps in left second molar between male and female (χ2 = 4.073, df = 2, p < 0.05). The strongest right - left correlation in the number of cusps was observed in maxillary 2nd molar (r = 0.809, p < 0.001). On application of Hardy-Weinberg equilibrium, it was found that there was variation in the observed frequencies and in the expected frequencies for the cusp number phenotypes in both the teeth. Keywords: Dental anthropology, Hardy-Weinberg equilibrium, Population genetics, Cusp pattern, Dental non metric trait