Isaac had two sons which are Esau and Jacob. The twelve tribes descend from Jacob and it's supposed Esau married canaanite women. This is why in the bible Jesus would argue with Pharisees and they'd say they have Abraham as their father, they were canaanites. Jesus also talked to the canaanite woman where she talked about the dogs eating crumbs at the childrens table, it's because she was a gentile.