Genesis 48:5

‘Your two sons, Ephraim and Manasseh, shall be mine.’ Later, the *tribes had the names of Jacob’s sons. But two *tribes were called the *tribe of Ephraim and the *tribe of Manasseh. And Ephraim and Manasseh were not actually Jacob’s sons. They were actually Jacob’s grandsons. So Ephraim and Manasseh were called Jacob’s sons.