Revealed: the feline family ties that bind all cats

Whether it is the fearsome sabre-toothed tiger of prehistoric times, the graceful cheetah or the domestic tabby, a DNA study has shown that cats are a tight-knit group of animals.

Research into the genetic relationship between the cats - living and extinct - has confirmed the common ancestry of some of the most terrifying yet beautiful predators on earth.

Within 15 million years - less than a quarter of the time since mammals rose to prominence after the demise of the dinosaurs - the cat family evolved to become the supreme land predators.

Unravelling the complex family tree of cats has traditionally relied on the skills of zoologists and palaeontologists - scientists trained to make judgements based on the shape, structure and age of bones.

In recent years a new tool has emerged based on the analysis of a special kind of DNA found in tiny cellular structures called mitochondria, the only DNA found outside the cell's nucleus.

Scientists from Britain, the US, Canada, Sweden and Australia used mitochondrial DNA from the blood of living cats and the bones of dead ones to update the Felidae family tree.

Their conclusions broadly support many of the judgements from earlier studies, but the scientists have also made some fascinating insights into how some cat species came into existence.

It was thought for instance that cheetahs may have evolved in the New World and moved to the Old World where they gave rise to the cheetahs alive today.

"There has been a lot of to-ing and fro-ing of animals across the land bridge separating North America and Asia at the Bering Strait," said Ross Barnett of Oxford University's Henry Wellcome Ancient Biomolecules Centre.

However, when the scientists analysed the mitochondrial DNA of the American "cheetah", a species called Miracinonyx trumani, they found that its closest relative was not the African cheetah but the American mountain lion or puma, Puma concolor.

"The data suggests that cheetahs originated in the Old World and that a puma-like cat invaded North America around six million years ago," Mr Barnett said.

Mitochondrial DNA from the bones of a museum specimen of Miracinonyx suggests that its closest relative is the American puma, and that they shared a common ancestor as recently as three million years ago - half the age of the Old World cheetah.

The difficulty with understanding the true origin of the American "cheetah" is that it had evolved to look similar to the true Old World cheetah because of what is known as convergent evolution - unrelated animals coming to look the same because they occupy the same ecological niche.

Another facet of the study shows that although the sabre-toothed cats belong to the same family as the domestic cat, they are the most distantly related members of the cat family. "The study confirms what the palaeontologists said about sabretooths being a separate subfamily within the cats," Mr Barnett said.

And what about the domestic cat? The present study does not assess the age of the moggy's last shared ancestor with the pumas, cheetahs and jaguars - its closest living relatives - but a study in Cyprus last year showed that man and cat have been close friends for at least 9,500 years.