Geometric morphometric study of sexual dimorphism in malaysian mandibles

Abstract

Background: Geometric morphometric is the statistical analysis of form based on Cartesian landmark coordinates. In this study, geometric morphometric techniques were used to study sexual dimorphism of mandible. Aims: The objectives were to determine mandible variation in size and shape, to determine the relationship between size and shape of mandible in different sexes, and to visualise allometry patterns of mandible. Methods: About 113 samples of adult human mandibles (65 males, 48 females) were analysed at the Universiti Kebangsaan Malaysia Medical Centre. Approximately 12 landmarks were placed on the 2-D image by landmarking software, and were analysed with MorphoJ. Results: The first five principal components were taken to represent the morphological variance with 83.64% cumulative variance. The mandible shape was used to determine sex. The variance visualization showed significant variation between male and female. The classification accuracy was 91.96%. Conclusion: Geometric morphometric is a good method to study sexual dimorphism of the mandible. Its potential may be developed in forensic anthropology to determine ancestry and age groups. MorphoJ and other softwares may be used in the application of geometric morphometric study of other bones.