We’re returning to the scene of the crime with another look at the latest techniques in the world of forensic genetics - can we really predict physical features or even ethnicity from your DNA, and what does this mean for our criminal justice system? Plus, is the ‘CSI effect’ real? And our gene of the month would be more at home at a rave than a lab. This is the Naked Genetics podcast for April 2018, brought to you in association with The Genetics Society.
In this episode
01:09 - Forensic genetics goes large
Forensic genetics goes large
with Ed Schwalbe, Northumbria University
As we heard in our previous podcast about forensic genetics, conventional forensic DNA analysis relies on looking at around 17 specific sites in the genome, which vary in size between individual people. But new techniques are allowing researchers to look at much more information from the whole genome, including the epigenetic information that reflects when genes are switched on and off.
So what can this kind of so-called big data tell us about populations and individual people, and how might it be useful to forensic scientists? Kat Arney spoke to one person who's trying to figure it out: Ed Schwalbe, Senior Lecturer in Bioinformatics and Biostatistics at Northumbria University in Newcastle.
10:28 - Genetic photofits - fact or fiction?
Genetic photofits - fact or fiction?
with Martin Evison, Northumbria University
We know that our genes have an influence on how we look, from the colour of our hair and skin to our height or the shape of our face. But when it comes to trying to predict what a criminal might look like from a sample of their DNA, what can we be sure about, what’s got potential, and what’s pure speculation? To find out, Kat Arney spoke to Martin Evison, professor of forensic science at Northumbria University.
16:56 - DNA's day in court
DNA's day in court
with Sophie Carr, Northumbria University
From what you see in TV crime dramas, if the detectives have got the DNA, that’s the clincher, right? Not so fast, says Sophie Carr, Associate Head of Department in the Applied Sciences at Northumbria University. There are some big questions that the judge and jury still need to ask when faced with DNA information from a crime scene, as she tells Kat Arney.
23:23 - Forensic genetics and ethics
Forensic genetics and ethics
with Matthias Wienroth, University of Newcastle
DNA evidence has been used in criminal cases since the 1980s, and as we’ve heard over the course of these two podcasts, the technology is advancing faster than ever. But is society keeping up with the pace of progress? According to Matthias Wienroth from the Policy, Ethics & Life Sciences Research Centre at Newcastle University, there are still some key ethical and societal crunch points that we need to address, as he explains to Kat Arney.
29:60 - Gene of the Month - Techno trousers
Gene of the Month - Techno trousers
Unlike most of our colourfully-named genes, techno trousers was first found in zebrafish, rather than fruit flies.
First identified in the rave heydays of the mid 90s through a large genetic screen by German scientists, techno trousers is one of four so-called ‘crazy fish’ genes, which when mutated cause distinctive changes in the movement of the animals. The other three are the slightly more sensible sounding roller coaster, wavy and hertz.
At just two days old, fish embryos with faulty techno trousers move in a wild and dramatic way, over-reacting to being gently prodded by making exaggerated bending movements with their tail, even flapping it against their head. And though you might be laughed out of Berlin’s trendy Berghain club for dancing like that, it does look a little bit like the fish are raving one out. Sadly, after four days they are all clubbed out, and become completely paralysed.
Fast-forward to 2012 and US researchers finally track down the gene itself, and discover that it encodes a protein called Eaat2b. This sits in the membrane around glial cells in the brain and shuttles small chemicals called glutamate in and out. Faults in the gene make the transporter overactive, making the brain cells overexcitable and explaining the fishes’ overexaggerated movements.
Importantly, faults in Eaat2b and glutamate shuttling in human brain cells are linked to conditions including epilepsy and neurodegeneration, so there’s a lot that scientists could learn about how to treat these diseases better by studying these funky little fish. Altogether now - big fish, little fish, cardboard box...