Does your dog have floppy ears or pointy ears, or maybe something in-between? History and biology explain why dogs come in all colors, patterns, shapes, and sizes.

Each participant in the X-Thousand Dogs Study will receive a report with information about their dog’s ancestry. In this post, Loyal’s Dr. John Lindo, who specializes in ancient DNA and canine evolution, explains how our understanding of the relationships between species has changed over time and what a DNA test can—and cannot—reveal about your dog’s ancestors.