Noah's three sons and their wives were among the people saved on the ark.
Lot, the nephew of Abraham, had two daughters who believed that the whole human race, other than themselves and their father, had been destroyed, so they got their father so drunk that he did not realize what was happening, and got themselves pregnant by him. That is the Biblical version of the origin of the Ammonites and Moabites.
I suspect the Ammonites and Moabites had different stories of their origins that did not involve incest.
They DID??
You must have a KJV bible; as the NIV says:
Genesis 19:30-38
30 Lot and his two daughters left Zoar and settled in the mountains, for he was afraid to stay in Zoar. He and his two daughters lived in a cave. 31 One day the older daughter said to the younger, Our father is old, and there is no man around here to give us childrenas is the custom all over the earth. 32 Lets get our father to drink wine and then sleep with him and preserve our family line through our father.
KJV=
31 And the firstborn said unto the younger, Our father is old, and there is not a man on the earth to come in unto us after the manner of all the earth.