Assessment of the dental morphological pattern of living Jordanian Arabs suggesting a genetic drift from the Western-Eurasia pattern: A cone beam computed tomography study.

Abstract

The objectives were to determine the expression frequency and sexual dimorphism of 15 dental morphological traits on the permanent dentitions of living Jordanians, and to compare the dental morphological pattern of this sample with those of 22 groups representing the various geographic regions of the world, for the purpose of assessing the population structure and genetic history of this group. Cone beam computed tomography images for the dentitions of 150 adult Jordanians (67 males, 83 females; age range = 18-58, mean ages 28.2, sd = 10.0 years) were studied in 2017. The traits were classified using the Arizona State University dental anthropology system, counted with the individual count method, and dichotomized according to the criteria of Scott & Turner for the purpose of group comparisons. Fisher's exact test for dichotomized scores was used to assess sexual dimorphism in these traits. Smith's Mean Measure of Divergence was used to measure all pairwise distance values among the groups. Statistically significant sexual dimorphism was found in two traits (i.e., UI1 shoveling and 4-cusped LM1), and apparent but statistically insignificant difference was found in three traits (i.e., UC canine mesial ridge, 3-rooted LM1, and 1-rooted LM2), all in favour of females. This study revealed that the dental pattern of Jordanians is distinct from the other reported Western Eurasian patterns and all other known dental patterns. This differentiated dental pattern suggests a genetic drift for this population from the Western Eurasian Ancestry.