Craniometric Determination of Sex and Ancestral Background of Northern Sudanese

Abstract

Background: Metric discriminant function is accepted as a tool for prediction of sex and ancestral background. It overcomes the high cost and preservation difficulties related to DNA analysis. Such investigations are lacking in the Sudan and the Arab world. Objectives: To develop discriminant function equations for determination of sex and ancestral affiliation using cranial osteometric measurements from Nubia, Kerma and computed tomography of the skulls of recent Northern Sudanese. Sex differences in old and recent Northern Sudanese crania will be compared with published series. Ancestral relation between recent Northern Sudanese, Old Sudanese and other populations will be explored. Material and Methods: Fifty eight measurements for 187 crania from Nubia (129 males, 58 females), seventy measurements for 179 crania from Kerma (83 males, 96 females) and seven radiological measurements for 110 crania from recent Northern Sudanese crania (69 males, 41 females) were recorded by the author using standard techniques. Data from published work were used for comparison with the three study groups. Intra and inter observer errors were catered for statistically. Various orders of statistical analysis were made using SPSS and PAST softwares. Results: Males had statistically significantly greater measurements than females. Complete crania showed a high degree of sexual discrimination with 88.7%, 90.2%, 81.8% success for Nubians, Kermans, and recent Sudanese respectively. The face showed discrimination in 83.2% of Nubians, 90.2% of Kermans and 70 % of recent Northern Sudanese. The vault showed discrimination in 82.4% in Nubia, 82.5% in Kerma and VIII 78.2% in recent Northern Sudanese. The base showed discrimination in 83.3% in Nubia and 85.9% in Kerma. The face measurements showed the highest sexual dimorphism percentage in recent Northern Sudanese followed by Nubians and then Kermans. The vault was more sexually dimorphic in Nubians. Using cranial indices, the recent Sudanese showed low cephalic height index compared to Nubians, Kermans, Jebel Moyans and other Africans. The recent Sudanese had also a relatively shorter cranial base length compared to maximum length. The recent Northern males and females had almost uniform frontal profile. The sex specific ancestral affiliation of recent Northern Sudanese to Nubians and Kermans was explored. Results showed that 63 % of the total males and females could be assigned correctly to their ethnic group. Nubians and Kermans were close to each other. The recent Sudanese females were assigned correctly in 75.6%, while males were assigned correctly in 84.1%. Recent Sudanese were found to have closer ancestry to Africans especially Nubian, Kermans, and Abyssinians than to the rest of the world. Conclusions: Discriminant function equations for sex and ancestral affiliation determination were developed for Nubians, Kermans, and recent Northern Sudanese. The pattern of sexual dimorphism in recent Northern Sudanese is different from that of most of contemporary populations. There is some degree of close ancestral relationship between Nubians and Kermans. Although there is some degree of commonality between the recent Northern Sudanese, Kermans and Nubians, yet there is obvious obtained discrimination accuracy in recent Northern Sudanese which may suggest some different ancestry. This study showed that IX recent Northern Sudanese tribes are not pure as they have some features in common with old Nubians and Africans.