DNA — deoxyribonucleic acid — is the molecular blueprint of living organisms.

In human beings, the genome consists of roughly three billion base pairs of genetic information arranged across twenty-three pairs of chromosomes in the nucleus of every cell, plus a much smaller genome in the mitochondria, the energy-producing structures found in almost all cells.

After death, DNA begins to degrade.

The cellular machinery that normally repairs DNA damage stops functioning.

Bacterial action breaks down organic material.

Water, oxygen, and radiation attack the molecular bonds that hold the DNA sequence together.