Midrasch zu Bereschit 46:7

Jacob heard this word, and he took his wives, and his sons, and his daughters, and the daughters of his sons. Another Scripture says, "With his daughter Dinah" (Gen 46:15). And all that he had, and he brought them to Egypt, as it is said, "His sons, and his sons' sons || with him," etc. (Gen 46:7). Another Scripture says, "With his daughter, Dinah" (Gen 46:15). Whereas another text says, "His daughters" (Gen 46:7), to teach thee that the daughters of Jacob were the wives of his sons. And all the seed of Jacob married their sisters and their blood-relations, so that they should not intermarry with the people of the lands, therefore they were called a true seed, as it is said, "Yet I had planted thee a noble vine, wholly a true seed" (Jer. 2:21).