According to an mtDNA study by Salas et al. (2005), the maternal lineages of African Americans are most similar to haplogroups that are today especially common in West Africa (>55%), followed closely by West-Central Africa and Southwestern Africa (<41%).
Correspondingly, Montinaro et al. (2014) observed that around 50% of the overall ancestry of African Americans traces back to the Niger-Congo-speaking Yoruba of southwestern Nigeria and southern Benin, reflecting the centrality of this West Africa region in the Atlantic Slave Trade.