How manÃ¢â‚¬â„¢s best friend overcame laws of natural evolution
A GENETICIST says he may have solved the mystery of how 350 breeds of dog evolved from a single ancestor, the grey wolf.
Matthew Webster of the Smurfit Institute of Genetics at Trinity College, Dublin, and colleagues at Uppsala University, Sweden, say the domestication of dogs may be allowing them to override the natural laws governing evolution.
They suggest natural selection, which ensures the survival of the fittest and weeds out genetic mutations that donÃ¢â‚¬â„¢t provide a survival advantage, was relaxed when dogs became domesticated. Living with people allowed harmful genetic variations to flourish that would never have survived in the wild.
This interference with nature could also explain why domestic dogs developed an array of diseases such as cancer, heart disease and epilepsy.
Ã¢â‚¬Å“Dogs exhibit more variation in size, appearance and behaviour than any other mammal, but the source of this huge diversity is something of a mystery,Ã¢â‚¬Â said Webster. Ã¢â‚¬Å“Dogs were domesticated from wolves very recently, on an evolutionary timescale, so all the variability seen in different dog breeds today has been generated in a relatively short time.Ã¢â‚¬Â
Scientists are still puzzled as to how such a scale of development could have taken place in a relatively short evolutionary timescale of 15,000 years.
Dogs evolved when wolves and early humans, which had been rivals for food, developed a mutually beneficial relationship. People began selecting those with desirable traits, such as guarding against intruders or hunting for food. In turn they were fed and given shelter.