Documenting Population Structure and Gene Flow Between Goats From Spain and Africa

The Strait of Gibraltar might have been a major route in the establishment of biological exchanges between Europe and Africa. In this way, the high within-breed diversity reported in Portuguese goats, an observation difficult to reconcile with the fact that these breeds are located at the  westernmost periphery of domesticate expansion, has been  explained in terms of ancient and multiple introductions of European (e.g. Italy, France) and North African caprines into the Iberian Peninsula. Indeed, an extensive survey of mitochondrial and Y-chromosome markers suggests that this might have been the case. In this experiment, we aimed to compare the population structure of Spanish and African goats and investigate the occurrence of gene flow between both areas. In order to accomplish this goal, we  analysed the autosomal variation of 1,310 goats, representing 28 Spanish and African breeds, with the aid of 25-29 microsatellites. Principal component analysis of genotype data revealed a strong genetic differentiation between European and African goats. Within Africa, a strong divergence between South African Boer goats and those with a North African origin was also observed. The mean F_ST was 0.072 and 92% of the genetic variation was comprised in the within-population component. Besides, Structure analysis indicated that the genetic background of Spanish breeds is fundamentally European. These findings suggest that goat migration between Africa and Spain might have been limited. We are currently in the process of estimating the magnitude of migration rates between both areas as well as inferring the existence of potential geographic barriers.