Original sentence: There are some large differences in the frequencies of occurrence of the various haplogroups compared with the modern population.These haplogroups included L1b, L2a, L3b, and L3d, of which L1b, L3b1, L3d appeared to be of West African origin
Edited sentence: "A mesolithic population carrying Group III lineages with the M35/M215 mutation expanded northwards from sub-Saharan to north Africa and the Levant.According to Underhill et al.At least 7.2% of European Males carry the African Haplogroup.At the Strait of Gibraltar, Africa and Europe are separated by only 15km of Ocean.At the Suez, Eurasia is connected to Africa.But Europe was periodically accessible by Africans due to fluctuations in the size and climate of the Sahara.Cruciani et al specifically state.E3b lineages would have then been introduced from the Near East into southern Europe by immigrant farmers, during the Neolithic expansion.Gene flow from Africa is primarily represented by haplogroup E, which entered Europe in the late pleistocene or early neolithic.Recently, it has been proposed that E3b originated in sub-Saharan Africa and expanded into the Near East and northern Africa at the end of the Pleistocene.The Levantine population of farmers that dispersed into Europe during and after the Neolithic carried these African Group III M35/M215 lineages, together with a cluster of Group VI lineages characterized by M172 and M201 mutations.The Mediterranean Sea and the Sahara Desert were formidable barriers to gene flow between Sub-Saharan Africa and Europe.The Nile river valley, which runs from East Africa to the Mediterranean Sea served as a bidirectional corridor in the Sahara desert, that frequently connected people from Sub-Saharan Africa with the peoples of Eurasia.There are some large differences in the frequencies of occurrence of the various haplogroups compared wth the modern population.These haplogroups included L1b, L2a, L3b, L3d and M1, of which L1b, L3b1, L3d appeared to be of West African origin