Human DNA Standard — A Q&A With NIST’s Becky Steffen

A woman in a lab coat loads samples into a white tray on a piece of scientific equipment.

How do you solve a crime using DNA? First, you have to find biological evidence — such as blood, other bodily fluids, or maybe just a few skin cells — that might be related to the crime. Then you can try to generate a DNA profile from that evidence. That is a genetic fingerprint, and no two people, other than identical twins, share it.

Once you have a DNA profile of a suspect, you can look for someone who matches it. After that, you’ll still have a lot of work to do to solve the crime, but that first step of generating the profile is crucial. If that’s not done carefully, you won’t get accurate results.