[Genetic and environmental characteristics in dento-craniofacial morphology--using materials from survey on Latin...

Most previous researches of hereditary characteristics of the craniofacial skeleton have used the twin-study method. In this study, dental anthropological materials were used to clarify genetic and environmental characteristics of the dento-craniofacial morphology. The sample consisted of four groups including Mexican Indians (N = 71), Peruvian Indians (N = 41) and their ancient ancestors: skulls of Mexican Indians (N = 33) and Peruvian Indians (N = 34). These groups shared the common origin of the Mongoloid race. Morphological similarity and difference among these groups were examined by principal component analysis and Student t-test using the dento-craniofacial data based on roentgenographic cephalograms and dental casts. The morphological similarity means the genetic characteristics which maintained during time differences between ancient and present times and throughout regional differences between Mexico and Peru. The morphological difference means the environmental characteristics which produced during the time differences and throughout the regional differences. Results were as follows: (1) The genetic morphological characteristics were found predominantly in the anterior cranial base, the dental arch form and to a certain extent in the basal portion of the mandible and the vertical dimension of the naso-maxillary complex. (2) The environmental characteristics were found predominantly in the muscular portion of the mandible, the alveolar portions of the maxilla and the mandible, the length of the dental arch and to a certain extent in the antero-posterior dimension of the maxilla.