Abstract
Previous research favours the idea that modern humans spread worldwide from Africa. For instance, autosomal diversity falls as geographical distance from Africa rises, and, through autosomal diversity, an area of origin for this worldwide expansion is indicated to be within Africa entirely. Declines are also known to happen for mitochondrial, X-chromosomal, and Y-chromosomal diversities. What was not known is if those diversities signal an area of origin which is totally in Africa. Additionally, there is disagreement regarding where in Africa the origin is. Considered in the present research was whether the expansion is suggested through various genetic diversities (including mitochondrial, X-chromosomal, and Y-chromosomal) and cranial traits (e.g., cranial size dimorphism), and where in Africa the expansion started. For each genetic or cranial variable, it was seen if the estimated area of origin was solely in Africa. To generally estimate where the expansion began in Africa, a centroid was calculated from potential origins that were obtained through indicators of the expansion. The area of origin was completely within Africa for each variable except one – for Y-chromosomal diversity, the area was possibly in Asia only. The centroid of the potential origins was in southern Africa. However, the support for a southern African origin (over elsewhere in Africa) could potentially reflect variation in non-African ancestry within Africa rather than the expansion. Nevertheless, a southern African origin was pointed to via the autosomal diversity of sub-Saharan African populations which had been adjusted for non-African ancestry. Southern Africa possible is the origin of the expansion.
Competing Interest Statement
The authors have declared no competing interest.
