The Targaryens wed brother to sister for three hundred years, to keep the bloodlines pure.

Some insist it is a natural change which does not affect the whole breed, while others actively fight to preserve the "pure" bloodline.

However, some argue that credit must be given to those breeders, as they are the ones who are keeping the bloodline pure.

However, the likelihood of a pure bloodline is very low.

The tests were dangerous and difficult, and only knights of pure bloodline could belong.

They were a far cry from the pure bloodlines of the sacrifices in Neville's ritual.

Or was it she, not the absent paternal parent, who had polluted the "pure" bloodline with her alien genes?

The use of tilapia in the commercial food industry has led to the virtual extinction of genetically pure bloodlines.

Both women showed the pure bloodlines of Wunderland aristocracy, the older one also in her expression; the younger looked subdued.

In ancient Hawaii, upper classes considered a marriage with a close royal family member to be an excellent way to preserve pure bloodlines.