We have 2 mongrels. We had their dna tested to see what breeds they were. It was complete nonsense. They came back with 20+ breeds each, not matching anything like what they look like.

For one of them it flagged his mother, who's owners had done the same, as a distant relative, 1% match. It also flagged pure breed dogs 1000s of miles away on a different continent as relatives. Possible but very unlikely.