Genetic Study may Track Dogs' Travels with Humans

A genetic study of a sexually transmitted canine cancer has offered clues to how dogs may have traveled around the world with their humans. Scientists analyzed the DNA of 440 nine tumors that exist today. Additional mutation allowed the scientists to trace the tumor's family tree. 

The research estimated the time since the mitochondrial transfer events by counting the number of mutations. One of them really seems to just track around maritime trade routes, in the last few hundred years. We found it along the coast of West Africa, in the Cape Vede Islands, Brazil, South Africa, India and some parts of southern Europe.

How Diet Shaped Human Evolution

The ancestor of modern humans shared the planet with Neanderthals, a close heavy-set relative that dwelled almost exclusively in Ice-Age Europe, until some 40,000 years ago. Neanderthals were similar to Homo sapiens, with whom they sometimes mated - but they were differences, Neanderthals were shorter and stockier with wider pelvises and rib-cages than their modern human counterparts.

But what was the reason behind the anatomical differences? A new study finds that the Ice-Age diet - a high-protein intake of large animals - triggered physical changes in Neanderthals, namely a larger ribcage and a wider pelvis.

According to the study, the bell-shaped Neanderthal rib-cage or thorax had to  evolve to accommodate a larger liver, the organ responsible for metabolizing great quantities of protein into energy. The heightened metabolism also required an expanded renal system to remove large amount of toxic urea, possibly resulting in a wide Neanderthal pelvis.

Source: Journal of Physical Anthropology