The Sub-Saharan Africans did not have an independent iron age

[Grumblenuts]

Putative migration waves out of Africa (and back):​

Human Dispersal Out of Africa: A Lasting Debate - PMC

Unraveling the first migrations of anatomically modern humans out of Africa has invoked great interest among researchers from a wide range of disciplines. Available fossil, archeological, and climatic data offer many hypotheses, and as such ...

www.ncbi.nlm.nih.gov

Advantages in life are the reason that some people advance before others.

Being alive long before others could certainly be advantageous. Ultimately we're all Africans.