Study of the genetic relationship and diversity patterns in the Azores based on 15 STR markers

Abstract The Azores, the largest Portuguese archipelago, is composed of nine islands unevenly distributed by three groups: the Eastern group (Sao Miguel and Santa Maria), the Central (Terceira, Pico, Faial, Sao Jorge and Graciosa) and the Western group (Flores and Corvo). Here, we describe the genetic diversity patterns for each Azorean island and their genetic relationship based on a total of 554 samples. Genotyping was carried out by the multiplex STR system PowerPlex ® 16 (Promega). The results demonstrate that the average gene diversity values vary between 0.768 and 0.797 for Corvo and Terceira, respectively. The comparison of these data with mainland Portugal (0.765) reveals higher values for the Azorean islands. The dendrogram shows that the most distantly apart are Flores and Corvo; however, there is no genetic differentiation between all islands. Moreover, we observe a clustering of the island's populations by their geographical and socio-cultural proximity. On the other hand, historical records mention a differential settlement between islands. The results show that, nowadays, there are no regional genetic differences in the archipelago due to internal migration. Taken together, the knowledge here obtained will provide insights about the allelic structure of health-related genetic variation in the Azorean population.