What separates the little guys from the big guys in the canine kingdom? The gene IGF-1 and the DNA that sits next to it, according to a team of researchers lead by K Gordon Lark and his team of researchers at the University of Utah.
The Domestic Dog shows the greatest range of body size of all mammals. "One of the big questions has always been, where does this range of sizes come from? By studying the Portuguese water dog, which has three-fold range of sizes – from 25 pounds to 75 pounds – we realized that IGF1 was a big player.
"The IGF1 gene's hormone helps humans and other mammals grow from birth to adolescence. But in small dogs, one or more mutations in the DNA next to the IGF1 gene suppress the gene's activity, keeping small dogs from growing larger." says Lark
You can read more about this discovery here.
