The Genetic Heritage of the Badiu

Genetic studies of Cape Verdean populations consistently show a tri-continental admixture: predominantly Sub-Saharan African, significant Iberian/European (reflecting Portuguese colonial presence and enslaver-enslaved genetic mixing), and minor North African/Berber components. Santiago Island — home of the Badiu — shows the highest African ancestry proportions in the archipelago.

Cape Verde is one of the best-documented cases of a founder effect in the Atlantic world: a small number of founding individuals (both African and European) gave rise to a large population, resulting in distinct allele frequency patterns not found in the source populations.

Y-chromosome haplogroup studies of Cape Verdean men reveal a complex picture. The dominant haplogroup is E-M2 (E1b1a), associated with Sub-Saharan African male lineages — reflecting the majority African ancestry of Santiago's enslaved population. This haplogroup is common among Mandinka, Wolof, Balanta, and other Senegambian peoples.

The significant presence of R1b haplogroups (predominantly European, particularly Iberian) reflects the genetic legacy of European (primarily Portuguese) male settlers, slaveholders, and traders who fathered children with enslaved and free African women.

The E-M81 haplogroup, associated with North African/Berber populations, indicates earlier contacts — possibly predating Portuguese colonization or reflecting North African individuals brought as intermediaries during the slave trade.

Mitochondrial DNA (maternally inherited) shows even higher African proportions than Y-DNA. The dominant haplogroups — L2 and L1 — are characteristic of West and Central African populations. This reflects the historical reality that enslaved women on Santiago Island were almost exclusively of African origin, while enslaved and free men included a larger (but still minority) European component.

European mtDNA haplogroups (primarily H) are present at lower frequencies, reflecting European women who settled in Cape Verde — primarily wives of Portuguese administrators and merchants.

Cape Verde is a textbook example of a founder effect — where a small original founding population gives rise to a much larger population, increasing the frequency of certain alleles. Genetic studies (Beleza et al., 2012; Verdu et al., 2017) confirm that Cape Verdean genetic diversity is notably lower than that of continental African populations, consistent with a bottleneck created by the initial small group of enslaved Africans and European settlers.

This also explains why certain genetic diseases and traits — including specific hemoglobin variants and other health-relevant markers — appear at elevated rates in Cape Verdean populations. This has public health implications for the diaspora that have been insufficiently studied.