This genetic information is what determines the biological characteristics of an organism and is passed from parents to offspring.

After death, the DNA in cells begins to degrade.

Bacteria consume the organic material of the body, including the cellular machinery that maintained and repaired DNA.

Chemical processes — hydrolysis, oxidation — attack the molecular structure of the DNA, breaking the long chains into short fragments and chemically modifying the bases that encode the genetic information.

Over time, less and less of the original genetic information survives.

In most burial conditions, the DNA in a body is essentially gone within a few thousand years.