Isaac’s genealogy first lists Esau's descendants (1 Chronicles 1:35–54) and then continues with Israel. The history of Edom is divided into three parts:
Esau's sons (1 Chronicles 1:35–37)
Seir's descendants (1 Chronicles 1:38–42)
The kings who ruled Edom (1 Chronicles 1:43–54)
This arrangement follows Genesis 36.