The results suggest a North African origin for these paternal lineages which, unlike maternal lineages, have declined to the point of being practically replaced today by European lineages.
Rosa Fregal, the principal author of the BMC Evolutionary Biology paper and a researcher from the Genetics Department of the University of La Laguna (ULL), told Servicio de Información y Noticias Científicas (SINC) that "whereas aboriginal maternal lineages have survived with a slight downward trend, aboriginal paternal lineages have declined progressively, being replaced by European lineages."
Experts have also analyzed an historic sample for La Concepción church (Tenerife), which dates back to the 17th and 18th centuries. With these data, they have established the impact of European colonization and the African slave trade, and have determined the evolution of paternal lineages in aborigines from the Canary Islands or Guanches, from the pre-Hispanic era to the present day.
The proportion of genetic contribution of Europeans, Aborigines and sub-Saharan in the Canarian population. Credit: Infographic&SINC
Although the contribution is now mainly European, scientists state that North African and Sub-Saharan contribution was higher in the 17th and 18th centuries. The explanation as to why there is a difference between the lineages of men and women from the Canary Islands stems from the diverse contributions of parental populations, and, above all, as a result of European colonization.
During this period, most relationships between men and women were between Iberian men and Guanches women, "due to the better social position of the former [Iberian men] compared to aboriginal males" Fregel explains. In addition to this, there was a higher mortality rate among male aborigines, who were displaced and discriminated against by conquerors. "Not only during the Crown of Castile Conquest in the 15th century, but also thereafter," the scientist affirms.
The researcher adds that in the case of Sub-Saharan lineages, both sexes were discriminated against equally, "and both maternal and paternal lineages have declined to date."
Traces of European colonization
A previous study of the Y chromosome in the current population of the Canary Islands demonstrated the impact of European colonisation on the male population in the Canary Islands, Fregal points out that, "When estimating the proportion of European lineages present in the current population of the Canary Islands, it was found that they represented more than 90%." Nevertheless, mitochondrial DNA studies in the current population demonstrated a notable survival of aboriginal lineages, where European contribution is between 36% and 62%.
Iberian and European contribution to male genetic patrimony in the Canary Islands increased from 63% during the 17th and 18th centuries to 83% in the present day. At the same time, male aboriginal genes decreased from 31% to 17%, and Sub-Saharan genes, from 6% to 1%.
As for women, European contribution is more constant, having moved from 48% to 55%, and aboriginal contribution, from 40% to 42%. The only decline observed in genetic contribution, from 12% to 3% in the last three centuries, has been in the case of Sub-Saharans.
Despite these advances, there are still mysteries to solve, such as how to determine whether the first inhabitants of the Canary Islands arrived by their own means or whether they were brought by force, "as there are no signs to ascertain whether they were aware of the navigation or if they came in one or several waves," Fregal concludes.