Researchers from the University of Chicago and several international institutions found that several groups of genes in humans and dogs—including those related to diet and digestion, neurological processes, and disease—have been evolving in parallel for thousands of years.

This parallel evolution was likely driven by the shared environments of humans and dogs, wrote the authors in a study published May 14 in the journal Nature Communications.

"As domestication is often associated with large increases in population density and crowded living conditions, these 'unfavorable' environments might be the selective pressure that drove the rewiring of both species," the authors surmise.

For example, living in crowded conditions with humans may have conferred an advantage on less aggressive dogs, leading to more