Viruses; DNA: Identical Twins: Dark Energy,

Why does a virus manage to infect us and make us ill so quickly? This week on Material World, Quentin Cooper speaks with structural biologist from the University of Oxford David Stuart who uses special X-rays, created by the Diamond Light Source in Oxfordshire, to expose those dirty tricks.

And how on earth do we see the invisible dark energy that makes up most of our universe? Astrophysicist Sarah Bridle from Manchester University joins Quentin in the studio to talk about her involvement in the Dark Energy Survey at an observatory in Chile and whether the Hubble Space Telescope can help in the search for this mysterious phenomenon.

And with the recent case of the French identical twins who have been implicated in serial rape, Quentin asks forensic geneticist Gill Tully from the Principal Forensics Services how DNA helps the police to find perpetrators. On the same topic, Tim Spector, a genetic epidemiologist from King's College London, suggests that identical twins might not actually be as similar in their genes as we previously thought.