A DNA study on Azoreans:

Genetic structure and origin of peopling in the Azores islands (Portugal): the view from mtDNA.

Santos C, Lima M, Montiel R, Angles N, Pires L, Abade A, Aluja MP.
Unity of Anthropology, Department BABVE, Faculty of Sciences, Autonomous University of Barcelona, 08193 Bellaterra (Barcelona), Spain. Cristina.Santos@uab.es

"...The values obtained for the various diversity parameters in the Azores archipelago indicate that the Azorean population, as a whole, does not exhibit the typical characteristics of an isolated population. The analysis of genetic data by groups of islands showed that the Western group exhibited particular features. The distribution of haplogroups in the Western group is very atypical, being significantly different from what is observed in the Eastern and Central groups. Furthermore, the diversity values are, in general, lower than those observed in other populations used for comparison. African haplogroups were found in all the groups of islands. Therefore the presence of Moorish and African slaves on the islands, as reported in historical sources, is supported by the mtDNA genetic data, especially in the Eastern group."
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12940917