God created Adam from the dust of the ground and breathed his life into him. He was created in God's Image.

After the fall (sin) Adam and Eve became mortal but their DNA still had God's fingerprints. They could embody the fullness their Creator had imbued within but not their offspring.

The first generations were closest to the perfection that was their DNA and thus lived hundreds of years. But over time and more people, more births, all that blood was diluted.

We as a species are all descendants of Adam and Eve but individually, we're not able to contain the fullness of information God imbued them with.