[Joao Pedro Martins]

Joao Pedro Martins  asked the Naked Scientists:

Hello,

In a programme about dating human bodies, you mentioned something  about some substance getting into our DNA. My question is: is the DNA of living people immutable in their lifetimes? And if it changes/can be changed, can this happen naturally or only by artificial/medical means?

Great podcast!

Thanks,

Joao Martins

What do you think?

[RD]

DNA can be changed (damaged) by chemicals, viruses and radiation.
These changes can result in the cell's death or malfunction such as cancer.

In gene therapy a benign virus is used to introduce a correction into faulty DNA code.

In gametes (sperm & eggs) there is genetic recombination: parts of the DNA sequence are rearranged.

[Karen W.]

Wow...I did not know that.. that is very interesting... does that mean that DNA evidence in Forensics etc. could potentially render someone innocent who may well be guilty or vice versa if the right circumstances prevailed...or perhaps is there a way to tell someones DNA has been changed..are there other markers to make sure they are correct in the case of a crime...?

[chris]

Hi Karen

thankfully not, because the changes that accrue over a lifetime secondary to mutations don't happen to every cell in the same way. Some cells will acquire one set of changes whilst another cell may have an entirely different set of mutations. But on average the core DNA fingerprint won't change, so we can still catch criminals and identify long lost relatives!

Chris

[Karen W.]

Cool Thanks Chris..It sounds so complicated...By core DNA fingerprint do you mean the base part of the DNA structure? That part remains the same, sort of like its skin so to speak changes but the original remains the same? How does that work...