11 Mar 2022

Forensics: Playing Hide & Seek With DNA


Forensic Science is the combination of many different fields:


  • Chemistry. Finding out about explosives or doping in sports.
  • Biology. DNA and genetic material and what we can determine from someone’s blood. Also, looking at the bacteria on someone’s clothes can tell us where they have been.
  • Engineering. Getting instruments that help us to do the job of forensic scientists in an easier or more reliable way.
  • Mathematics. A big part of forensics is asking if the evidence they are looking at is enough to say that something happened. Forensic scientists have to use mathematics to assess the probability of each situation.
  • Computer Science. Forensic Scientists use AI and machine learning to assess the probability of events. Cybercrime is also assessed by Forensic Scientists.
  • Other fields. Pattern analyses are important to assess where the blood came from and what the cause was, or how a glass window was broken, was it broken from the outside or inside and what broke it?


human dna gif | Stemettes Zine

DNA intelligence is all about the DNA that all of us have which is unique to us. This is all over us, it’s in our hair and in our blood. From our DNA you can get information on someone’s skin colour, hair colour, ancestry, eye colour and age. Human DNA is 99.9% similar to each other, in fact, human DNA is 80% similar to bananas!

DNA is made up of 4 different nucleotide bases: A, T, C, & G. These nucleotides bond together to make a long chain of DNA that is slightly different from person to person, with just a few letters differing.

atcg dna nucleotides | Stemettes Zine

DNA Intelligence takes the DNA from a drop of blood and looks for the small differences in the DNA chain to predict what someone looks like. DNA Intelligence also takes into account where someone comes from. To put this into perspective, a human cell contains about 6 billion nucleotide pairs, and only 6 nucleotide differences tell a DNA Intelligence expert the eye colour of the suspect, and 41 nucleotides determine someone’s heritage.

Age cannot be determined by looking at the DNA chain as your DNA does not change as you age. Instead, DNA Intelligence experts need to look at the structure of the DNA itself. Throughout your life, your DNA needs to stop or start producing some characteristics, for example, at some point, you need to stop growing so your DNA needs to stop this, or at some point, you will start producing grey hairs and your DNA changes structure to control this. So, DNA Intelligence experts look for the structural changes in the DNA to find out some age-related characteristics about you.

A massive thank you to Anastasia, a Postdoctoral Research Associate in Forensic Genetics, for leading this session during February Explore 2022.


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