Cool Science: DNA Fingerprinting

| On
June 21, 2014
It's kind of weird, but one of my dream jobs (I have many, ranging from stationery designer to CEO. #casual.) would be to work as a medical examiner. Okay, just hold up a sec and actually think about it. Just ignore the dead bodies for a minute and it's actually a super cool job. You get to work with crime and the police department, you get to work with the justice system, you get to work with science. A perfect fit for me! Plus I probably would have a bad bedside manner because I'm grumpy in the mornings. No need for a good bedside manner with dead people! Too far? Sorry.

But I do think the crossroads of science and justice can be really, really interesting, especially for a casual scientist. One common scientific procedure in crime (at least according to Law & Order SVU, which may or may not be my main source for this post) is DNA fingerprinting. 

The science of fingerprinting and classifying finger prints is called dactyloscopy, and I'm really only telling you that because it's a cool word and you can feel intellectual if you casually mention it in conversation. But the actual process of connecting a fingerprint with DNA (your genetic ID) is called electrophoresis

Electrophoresis takes place in a bunch of steps. First, DNA is isolated and basically cut in half. Then, little chemicals called restriction enzymes cut up the DNA at certain spots, making a bunch of segments of different sizes. The restriction enzymes cut every person's DNA at different places, making the lengths of segments different in every person.

These segments of DNA are called RFLPs (restriction fragment length polymorphisms)...but they are pronounced like "riff-flips", which is sort of fun. So these RFLPs are put in a gel and a charge is sent through the gel, which makes the RFLPs sort themselves by size. Once dyed, these give a display that can be compared against someone's DNA in a data base. It looks like this.

This chart can also be used to tell someone's maternity or paternity. Each of a person's lines (which represent a RFLP, a segment of DNA) is identical to either their mother's or father's. 

If you're interested in learning more about DNA fingerprinting, here are a few resources:
How interesting is forensic science?! And how will you use dactyloscopy and RFLPs in a conversation today?

P.S. My favorite recent science articles and why science means we might replace streetlamps with glowing trees #nbd.

Be First to Post Comment !
Post a Comment

Klik the button below to show emoticons and the its code
Hide Emoticon
Show Emoticon

Custom Post Signature

Custom Post  Signature