Before revision: In 4000 BP (or even earlier during the Mesolithic) , there may have been a population that traversed from Africa (e.g., West Africa or West-Central Africa), through the Strait of Gibraltar, into the Iberian peninsula, where admixing between Africans and Iberians (e.g., of northern Portugal, of southern Spain) occurred.
After revision: In 4000 BP , there may have been a population that traversed from Africa (e.g., West Africa or West-Central Africa), through the Strait of Gibraltar, into the Iberian peninsula, where admixing between Africans and Iberians (e.g., of northern Portugal, of southern Spain) occurred.