I will add this. I state this in every thread on Liberia and Sierra Leone. The American Black people that returned to Liberia and Sierra Leone were almost certainly heavily descended from people that were originally from the areas around Liberia, Sierra Leone, Senegal, Gambia, Ivory Coast and Guinea.
We know this is true, because the English and American slavers focused very heavily, not exclusively though, on taking slaves from the grain/rice coast between 1670 through roughly 1800. Those slaves were taken to work on rice plantations in the USA States of South Carolina, North Carolina and Georgia.
So the people that returned to Liberia and Sierra Leone had a genetic connection to that area, because they were only roughly 2 to 4 or so generations removed.
Bunce Island History | The Gilder Lehrman Center for the Study of Slavery, Resistance, and Abolition