E-M33 is found most often in West Africa, and today it is especially common in the region of Mali. One study has found haplogroup E-M33 Y-chromosomes in as much as 34% (15/44) of a sample of Malian men, including 2/44 E-M44 and 13/44 E-M33/M132(xE-M44). In particular, the Dogon people of Mali have been found to carry haplogroup E-M33 with a frequency as high as 45.5% (25/55), making it perhaps the most common Y-DNA haplogroup in this population, though haplogroup E-P1 appears to be almost equally frequent among the Dogon (24/55 = 43.6%). Another study has found haplogroup E-M33 in 15.6% (44/282) of a pool of seven samples of various ethnic groups in Guinea-Bissau. Haplogroup E-M33 also has been found in samples obtained from MoroccanBerbers, Sahrawis, Burkina Faso (including E-M33/M132(xE-M44) in 2/20 = 10% Fulbe and 2/37 = 5.4% Rimaibe), northern Cameroon (including E-M44 in 9/17 = 53% Fulbe and E-M33/M132(xE-M44) in 3/15 = 20% Tali), Senegal (7/139 = 5.0%), Ghana (1/29 = 3% Ga, 1/32 = 3% Fante), Sudan (including 5/32 = 15.6% Hausa and 3/26 = 11.5% Fulani), Egypt,Calabria (including both Italian and Albanian inhabitants of the region), Italians from Trentino in northeastern Italy, and Romanians from Constanţa.
Prior to 2002, there were in academic literature at least seven naming systems for the Y-Chromosome phylogenetic tree. This led to considerable confusion. In 2002, the major research groups came together and formed the Y-Chromosome Consortium (YCC). They published a joint paper that created a single new tree that all agreed to use. Later, a group of citizen scientists with an interest in population genetics and genetic genealogy formed a working group to create an amateur tree aiming at being, above all, timely. The table below brings together all of these works at the point of the landmark 2002 YCC tree. This allows a researcher reviewing older published literature to quickly move between nomenclatures.
^ abcdeFulvio Cruciani, Piero Santolamazza, Peidong Shen et al., "A Back Migration from Asia to Sub-Saharan Africa Is Supported by High-Resolution Analysis of Human Y-Chromosome Haplotypes," American Journal of Human Genetics 70:1197–1214, 2002.
^ abcdeElizabeth T Wood, Daryn A Stover, Christopher Ehret et al., "Contrasting patterns of Y chromosome and mtDNA variation in Africa: evidence for sex-biased demographic processes," European Journal of Human Genetics (2005) 13, 867–876. (cf. Appendix A: Y Chromosome Haplotype Frequencies)
^ abcdeAlexandra Rosa, Carolina Ornelas, Mark A Jobling et al., "Y-chromosomal diversity in the population of Guinea-Bissau: a multiethnic perspective," BMC Evolutionary Biology 2007, 7:124.
^ abcHisham Y. Hassan, Peter A. Underhill, Luca L. Cavalli-Sforza, and Muntaser E. Ibrahim, "Y-Chromosome Variation Among Sudanese: Restricted Gene Flow, Concordance With Language, Geography, and History," American Journal of Physical Anthropology (2008).
^Peter A. Underhill, Peidong Shen, Alice A. Lin et al., "Y chromosome sequence variation and the history of human populations," Nature Genetics, Volume 26, November 2000
^Ornella Semino, A. Silvana Santachiara-Benerecetti, Francesco Falaschi et al., "Ethiopians and Khoisan Share the Deepest Clades of the Human Y-Chromosome Phylogeny," American Journal of Human Genetics 70:265–268, 2002.
^J. R. Luis, D. J. Rowold, M. Regueiro, B. Caeiro, C. Cinnioğlu, C. Roseman, P. A. Underhill, L. L. Cavalli-Sforza, and R. J. Herrera, "The Levant versus the Horn of Africa: Evidence for Bidirectional Corridors of Human Migrations," American Journal of Human Genetics 74:532-544, 2004.
^Vincenza Battaglia, Simona Fornarino, Nadia Al-Zahery et al., "Y-chromosomal evidence of the cultural diffusion of agriculture in southeast Europe," European Journal of Human Genetics (2008), 1 – 11
^E. Bosch, F. Calafell, A. González-Neira et al., "Paternal and maternal lineages in the Balkans show a homogeneous landscape over linguistic barriers, except for the isolated Aromuns," Annals of Human Genetics (2006) 70, 459–487