Personality is more than skin deep, in dogs as well as their masters Elliott Erwitt/Magnum Photos

FIDO loves to cuddle on the sofa, Spot’s a cheeky hound with a good eye for an unguarded slice of roast lamb, and Rover is just the best, most caring babysitter. As dog owners and lovers everywhere will tell you, pooches have personality. Some of that – quite a bit of it, in fact – is down to breeds. Terriers are notorious for their boundless energy. Border collies like to chase things. Pointers point. German shepherds and poodles learn quickly, bulldogs and beagles not so much.

All this makes dogs more than just great pets. They’re also ideal subjects for geneticists eager to understand one of the great mysteries still remaining in biology: how complex behaviours are encoded in genes. If scientists can crack the code for dogs, we may be able to understand – and perhaps better manage – not only our loyal companions’ behaviour, but our own as well.

Geneticists have known for decades that dogs are perfect for gene prospecting. The comparison may seem a touch unkind, but dog breeds aren’t unlike strains of lab rats: each one is essentially an inbred line reared over generations to be nearly identical clones of each other. That makes both types of animal well suited to studies seeking to understand which gene does what. If you can identify subtle genetic differences between almost identical individuals, you can try to link those to variations in physical appearance, health or behaviour. It’s a far cry from us humans, who tend to be very outbred and unsuited to genetic studies, …