The Milkshake Gene - (LCTL) Are you dairy intolerant? If so, you’re not alone – more than 90% of people in some parts of the world are unable to properly digest milk, cheese and other dairy products. Most other animals are also unable to drink milk once they leave babyhood behind. So why did some of us evolve the ability to tuck into cheese, butter and cream with a vengeance? The answer lies in the history of human evolution and the early days of farming.

The Cyclops Gene - (SHH) Building a baby is a complicated business, with thousands of genes to be turned on or off at exactly the right time and in the right place. One of them is Sonic Hedgehog – named after the computer game character – which has its genetic fingers in all kinds of developmental processes. Sonic Hedgehog helps to decide how many bits you have, where they go, and whether you’re symmetrical, so it’s not surprising that any mistakes can have potentially devastating consequences. The most severe faults lead to ‘cyclops’ foetuses, while less serious changes are responsible for extra digits – like the reputed extra finger of Anne Boleyn, or Ernest Hemingway’s notorious six-toed cats. We take a look at the mind-bogglingly intricate process of creating a body, and the key role our favourite blue hero plays in making sure everything goes to plan. Show less