107,000 years ago or approx. 90,000 YBP. Its age and widespread distribution and diversity across the continent makes its exact origin point within Africa difficult to trace with any confidence, however an origin for several L2 groups in West or Central Africa seems likely, with the highest diversity in West Africa. Most of its subclades are largely confined to West and western-Central Africa. Around 18,000 BP, Mende people, along with Gambian peoples, grew in population size. In 15,000 BP, Niger-Congo speakers may have migrated from the Sahelian region of West Africa, along the Senegal River, and introduced haplogroup L2a1 into North Africa, resulting in modern Mauritanian peoples and Berbers of Tunisia inheriting it. Between 11,000 BP and 10,000 BP, Yoruba people and Esan people grew in population size. As early as 11,000 years ago, Sub-Saharan West Africans, bearing macrohaplogroup L (e.g., L1b1a11, L1b1a6a, L1b1a8, L1b1a9a1, L2a1k, L3d1b1a), may have migrated through North Africa and into Europe, mostly into southern Europe (e.g., Iberia). Autosomal DNA Between 2000 BP and 1500 BP, Nilo-Saharan-speakers may have migrated across the Sahel, from East Africa into West Africa, and admixed with Niger-Congo-speaking Berom people. Medical DNA Sickle Cell Amid the Green Sahara, the mutation for sickle cell originated in the Sahara or in the northwest forest region of western Central Africa (e.g., Cameroon) by at least 7,300 years ago, though possibly as early as 22,000 years ago. The ancestral sickle cell haplotype to modern haplotypes (e.g., Cameroon/Central African Republic and Benin/Senegal haplotypes) may have first arose in the ancestors of modern West Africans, bearing haplogroups E1b1a1-L485 and E1b1a1-U175 or their ancestral haplogroup E1b1a1-M4732. West Africans (e.g., Yoruba and Esan of Nigeria), bearing the Benin sickle cell haplotype, may have migrated through the northeastern region of Africa into the western region of Arabia. West Africans (e.g., Mende of Sierra Leone), bearing the Senegal sickle cell haplotype, may have migrated into Mauritania (77% modern rate of occurrence) and Senegal (100%); they may also have migrated across the Sahara, into North Africa, and from North Africa, into Southern Europe, Turkey, and a region near northern Iraq and southern Turkey. Some may have migrated and introduced the Senegal and Benin sickle cell haplotypes into Basra, Iraq, where both occur equally. West Africans, bearing the Benin sickle cell haplotype, may have migrated into the northern region of Iraq (69.5%), Jordan (80%), Lebanon (73%), Oman (52.1%), and Egypt (80.8%). Schistosomes According