Here's why:
* All cells have the same genome: Each cell in your body contains a complete copy of your genetic code, called the genome. This genome is stored in DNA molecules.
* Exceptions exist: There are a few exceptions to this rule.
* Red blood cells: Mature red blood cells lack a nucleus and therefore lack DNA.
* Mitochondrial DNA: Mitochondria, the energy factories of cells, have their own separate DNA called mitochondrial DNA (mtDNA). mtDNA is inherited solely from the mother.
Therefore, while the majority of cells in the human body will have the same DNA sequence, there are a few exceptions.
