Complex sentence: Iberia stands out among other southern European populations as having the highest levels of ancestry originating both in North Africa as well as in Sub-Saharan Africa which is largely ascribed to the long Islamic presence in the Iberian peninsula and possibly African slavery.
Split into simpler sentences: Iberia stands out among other southern European populations as having the highest levels of ancestry originating in North Africa, as well as in Sub-Saharan Africa. This is largely ascribed to the long Islamic presence in the Iberian peninsula and possibly African slavery.