There is a 1000 year separation between Genesis 1 and a man without a name was placed in the Garden. Adam was created on day 6 and was a son of God along with many sons of God who were both male and female like Adam was, because the Female Eve was taken out of Adam. But this happened 1000 years later. The Generations of Genesis 2:4 went on for 1000 years before God planted a Garden.
"These are the generations of the heavens and of the earth, when they were created, in the day, that the Lord God made the earth and the heavens,"
Genesis 2:3
"God blessed the seventh day and separated it as holy; because on that day God rested from all his work which he had created, so that it itself could produce."
So the sons of God created on the 6th day multiplied and filled the earth for 1000 years before the Garden of Eden.
Genesis 2:18-20
18
Adonai, God, said, “It isn’t good that the person should be alone. I will make for him a companion suitable for helping him.”
19 So from the ground
Adonai, God, formed every wild animal and every bird that flies in the air, and he brought them to the person to see what he would call them. Whatever the person would call each living creature, that was to be its name.
20 So the person gave names to all the livestock, to the birds in the air and to every wild animal. But for Adam there was not found a companion suitable for helping him.
Adam was called a person without a name until after this person named the animals. Then God called him Adam.
Adam was in the Garden for 30 years. Eve was taken out of Adam, only after 1000 years, after a Garden was planted, after God filled the Garden with plants, trees, and animals, and after a man named the animals, and after God named this man Adam, then Eve was formed from Adam. They both were 30, and they both lived in the Garden for 30 years. Only Cain and Abel were born in the Garden. Cain was probably around 20, and Abel was 15, when Adam and Eve DISOBEYED. There was no dna from the tree. God just literally changed how the earth would now react to only Adam and Eve, in a perfect world, Satan now sin filled humans.
Both Adam and Eve had to wait 100 years. They were 130 years old when they had Seth. They were 30 years old when sin happened, and they had to wait 100 years, making them 130, when Seth was born. Seth was born in the image of fallen Adam, and was not a son of God.
Cain and Abel may have hung out for another 5 to 10 years, and Cain got jealous. God warned him that sin was waiting outside of the Garden, at the door. The angel could not let it in. But then Cain killed Abel and he to had to leave God's presence, and no one remained in the homestead of a perfect Eden.
Cain was cast out into the middle of a world populated by the sons of God. They would have judged and killed him, and the earth would not give him any food. He was cursed with a mark.
This would identify him even in a son of God body. His biology was not changed like Adam and Eve. His wife was a son of God, and their children were workers in bronze, and they had a city and trade to support Cain who was cursed.
Eventually the sons of God married into the fallen genealogy of Adam. Until Noah was more righteous than even the sons of God.
God destroyed them all and the perfect world in the Flood and only Noah, and his 3 sons populated the 3 types of mankind. Caucasian, Dark skinned, and in between. The nations were condensed around Mesopotamia, until God confounded English, and created Indo-European tongues. It has taken about 4500 years to get all humanity speaking English as one again.