GENETIC AND ENVIRONMENTAL-INFLUENCES ON FACIAL PROFILE

Observed variation in facial morphology results from the influences of both genetic and environmental factors. To investigate the role of ge netic influences on variation in facial profile, lateral photographs o f 23 male and 19 female monozygous (MZ), and 15 male and 22 female diz ygous (DZ) twin pairs were selected from the records of the South Aust ralian Twin Study. Soft tissue landmarks and facial profiles were iden tified, traced and digitized. Linear and angular measures defined by t he landmarks were calculated and a series of Fourier functions derived to describe the facial profiles. These Fourier amplitudes were interp reted in terms of the specific regions which they represented. Correla tions within MZ pairs were consistently higher than within DZ pairs fo r both the facial dimensions and the Fourier amplitudes, providing evi dence of significant genetic contribution to facial convexity, facial height and facial depth. Variability in nose and lip morphology appear ed to be under stronger environmental influence.