According to the author of Genesis, this verse is like listing the names of a family to show where different groups of people came from, explaining that these were the children of a woman named Keturah. It's like saying Keturah had these boys, and they grew up to have their own families too.
Genesis 25:4: And the sons of Midian; Ephah, and Epher, and Hanoch, and Abida, and Eldaah. All these [were] the children of Keturah.
1 Chronicles 1:33 provides genealogy-related information that can differ from the accounts in Genesis, leading to variations in lineage records.
1 Chronicles 1:33: And the sons of Midian; Ephah, and Epher, and Henoch, and Abida, and Eldaah. All these [are] the sons of Keturah.