Principal Component Analysis for a) several African populations and b) Guinea-Bissau ethnic clusters, based on haplogroup frequencies. a) The 1st PC captures 42.6% of the variance and 16.9% are under the responsibility of the 2nd PC. For details on populational datasets see Additional file 2. The codes in italic refer to the following populations: Morocco Arabs: Ar [1,34], Mar ; Morocco Berbers: Bb , MBb ; Algeria: Alg , Aar-Algerian Arabs ; Tunisia-Tun1 , Tun2 ; West Sahara: Sah-Saharawis ; Egypt: Egy1 , Egy2 ; Sudan: Sud ; Ethiopia: Eth , Or-Oromo, Amh-Amhara [5,7]; Kenya: K&K-Kikiu & Kamba, Maa-Maasai ; Uganda: Gan-Ganda ; North Cameroon: Po-Podokwo, Mad-Mandara , Ou-Ouldeme, Daba [1,7,26], NCAdaw-Fali, Tali [1,26], Fca-Fulbe [1,26]; South Cameroon: SCBantu-Bassa, Ngoumba , Bak-Bakaka, [1,7], Bam-Bamileke [1,26], Ewo-Ewondo [1,26], Bko-Bakola Pygmies ; CAR: Bik-Biaka Pygmies [2,7]; DRC: DRCBantu-Nande, Herna ; Mb-Mbuti Pygmies [2,7]; Guinea-Bissau: EJA-Felupe-Djola, BJG-Bijagós, BLE- Balanta, PBO-Papel, FUL-Fulbe, MNK-Mandenka, NAJ-Nalú (Present study); Burkina Faso: Mo-Mossi [1,26], Ri-Rimaibe [1,26], FBF-Fulbe [1,26]; Gambia/Senegal: Wo-Wolof , Mak-Mandinka ; Mali: Mal , Do-Dogon ; Ghana: Ewe, Ga, Fan-Fante ; Senegal: Se ; Namibia: Her-Herero, Amb-Ambo , Ku-!Kung, Sekele [1,7,26], CKh-Tsumkwe San, Dama, Nama ; South Africa: ST-Sotho-Tswana, Zu-Zulu, Xh-Xhosa, Sh-Shona , Kho-Khoisan . b) The PCA captures 87.0% of the variance with 74.0% and 13.0% attributed to the 1st and 2nd PC, respectively. The 1st PC reflects an axial proportion of E3a* vs. E1* where Papel and Felupe-Djola retain the higher proportions of the later. E3a* is again a main influence in the 2ndaxis against that of R1b and E3b1, placing Mandenka apart from Bijagós and Fulbe.