The close connection between humans and dogs has yielded more than best friendships. For scientists studying human evolution, that connection provides a valuable window into the development and migration patterns of man.
Recent research published in the Journal of Human Evolution indicates that dogs may have been latecomers to North America, arriving around 10,000 years ago, thousands of years after humans first made the journey across the land bridge from Siberia. Scientists had previously theorized that dogs arrived at the same time as humans but speculate that the dogs could have came over alongside a later wave of migrants.
The team from the University of Illinois at Urbana-Champaign compared the mitochondrial DNA of 84 individual dogs whose remains have been extracted from early human settlements throughout North America. It was the largest collection of ancient dog DNA ever analyzed; while it showed that the canines’ genetic diversity only dates back about 10,000 years, one researcher cautioned that the particular genome region they focused on "may mask the true genetic diversity of indigenous dogs in the Americas, resulting in the younger date for dogs when compared with humans."
Still, 10,000 years ago is around the same time of the earliest deliberate dog burial found in North America. The study also revealed evidence suggesting that some dogs likely cross-bred with indigenous wolves and that some early North Americans may have been deliberately breeding the animals—a process that has led ultimately to smushed faces, stubby legs, head poofs, and the pet sweater industry.