Why are the Basques so high in Rh negative blood?

The following is a claim:

          When the Rh-negative people, we now call Berbers, first came to what is today Euskadi (pronounced: oos-ká-di), the Basque country, they found there a small but most creative population which, according to the archaeologists, may have lived there already for some 20,000 years before the Rh-negative peoples arrived. The two peoples were quite different genetically. The endemic population had brachycephalic (round) skulls. The Berbers had dolichocephalic (long) skulls, wedge-shaped heads, wide at the temples and narrowing to a pointed chin and they were Rh-negative. The most amazing features of the area are the many beautifully painted cathedral caves of enormous antiquity, decorated with great difficulty and personal sacrifice by artists, in honor of the “Great Goddess”. In southern India, such cave paintings are still being made, and all the artists are women, which may have been the case also in the Basque country. To this day, the Rh-negative people live mainly in the coastal areas.  They were without doubt, the most experienced sailors of the Atlantic. They probably arrived in the Bay of Biscay about 10,000 bce. to hunt reindeer for sails, which were greatly coveted by mariners because of their durability and light weight. The original round-headed people do not appear to have belonged to the tribes of the Sea Peoples and even today, their type is not common among the Basque fishermen.

http://www.faculty.ucr.edu/~legneref/bronze/seapeopl.htm#rhnegativepopulation