The discovery of two SNPs (V38 and V100) by Trombetta et al. (2011) significantly redefined the E-V38 phylogenetic tree. This led the authors to suggest that E-V38 may have originated in East Africa. V38 joins the
West African-affiliated E-M2 and the
Northeast African-affiliated E-M329 with an earlier common ancestor who, like E-P2, may have also originated in
East Africa. According to Wood et al. (2005) and Rosa et al. (2007), such population movements changed the pre-existing population Y chromosomal diversity in
Central,
Southern, and
Southeastern Africa, replacing the previous
haplogroup frequencies (haplogroups
A and
B-M60) in these areas with the now dominant
E1b1a1 lineages. Traces of earlier inhabitants, however, can be observed today in these regions via the presence of the Y DNA haplogroups
A1a, A1b, A2, A3, and
B-M60 that are common in certain populations, such as the
Mbuti and
Khoisan. Shriner et al. (2018) similarly suggests that haplogroup E1b1a-V38 traversed across the
Green Sahara from
east to west around 19,000 years ago, where E1b1a1-M2 may have subsequently originated in
West Africa or
Central Africa. Shriner et al. (2018) also traces this movement via
sickle cell mutation, which likely originated during the Green Sahara period. ==Ancient DNA==