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DNA & biological evidence

Overview

What is DNA evidence? And how is DNA used to solve crimes? DNA is a complex molecule that contains the instructions for building and maintaining the bodies of humans and other organisms. With the exception of red blood cells, every cell in your body has DNA. And with the exception of identical twins, everyone’s DNA is different. If someone leaves blood, semen or other biological material at a crime scene, scientists can use it as DNA evidence and create a DNA profile, or genetic fingerprint of that person. That profile can be used to search a DNA database for a possible suspect, to associate a suspect with evidence left at a crime scene, or to link two crimes that may have been committed by the same person. DNA profiles, and some of the complications in using them, are described in this article about enhanced DNA fingerprints.

What we do

NIST has played a key role in the historical development of forensic DNA analysis. Today, our forensic DNA program has three major components.

The Research

Projects & Programs

Digital PCR

Digital PCR (dPCR) is a method used to quantify nucleic acids (DNA, RNA, cDNA). At NIST we are using microfluidic and emulsion-based dPCR platforms for

Additional Resources Links

News

woman loads small plastic vials containing human DNA into a large machine

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

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
A white cardboard box with blue lettering.

Forensic Science Organization to Draft Standards for Sexual Assault Examinations

OSAC logo

NIST Launches an Updated Organization of Scientific Area Committees for Forensic Science

Man in white lab coat using a pipette under a hood

Two New Forensic DNA Standards Added to the OSAC Registry

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