In billions of years organisms learnt how to interact with their environment and how certain skills are superior over others. However we all know that genetics are a complicated topic and that sometimes small "errors" happen which are responsible for the biodiversity on our planet. So after billions of years of genetically mutations the homo sapiens appeared in east Africa (according to the current stage of research). So... I did some research myself with a little help of Google and searched, were the homo sapiens' closest relatives are located.
Nowadays Chimpanzees and Gorillas normally live in Central Africa which supports the theory of evolution for a common ancestor.
Carefully: Apes are not the homo sapiens' ancestor, at some point of evolution they shared the same ancestor and developed differently. (still the gene pool is very close till now with 90-99 percent of a genetic match).
So, after billions of years apes in central Africa still are likely to have a darker skin color because it protects them from the strong radiation of the sun. The common ancestor was likely to have a darker skin color. And as genetical mutations and evolution are a slow and steady process it is most likely that the first homo sapiens also had a darker skin color.
I myself am pretty sure that lighter skin colors appeared first after the homo sapiens decided to travel northern places.