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decades, dog lovers have been incorrectly calculating the age their pet pooches. People have traditionally worked their dog's age "human years" by multiplying seven. However, researchers the University of California San Diego School of Medicine in the USA have come with a new formula. They say it more precisely determines canine age. Their new method requires a little more than simple mental arithmetic to work a dog's age. It involves a comparison the genomes of dogs and humans. Scientists had to analyse how DNA changes as humans and dogs age. The scientists regard such DNA analysis as the best way to measure the ageing speed mammals.

The researchers analysed blood samples 105 Labrador retrievers. After a bit number crunching, they created a graph to show the different rates which canines and humans age. They said a one-year-old dog is similar to a 30-year-old human, while a four-year-old hound is comparable to a 52-year-old person. Researcher Trey Ideker said the time a dog reaches seven years old, its ageing slows. He said: "This makes sense. When you think it, a nine-month-old dog can have puppies, so we already knew that the 1:7 ratio wasn't an accurate measure age." The researchers said their new formula doesn't fully address the fact that different breeds dog age different speeds.

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