Overview

• Published August 28 in Science, the study tracked 266 trait-associated markers in ancient and modern horses and identified nine with strong signatures of selection.
• Early domestication about 5,000 years ago shows selection near ZPFM1 consistent with reduced anxiety and greater tameness.
• Intensive selection at the GSDMC locus between roughly 4,700 and 4,200 years ago ranks among the strongest signals during the rise of the modern horse lineage and is tied to traits that support riding.
• Functional tests that modified the GSDMC region in mice produced straighter spines, stronger limbs, and enhanced locomotion, supporting a causal role for load-bearing and movement.
• The favored GSDMC variant swept to near fixation within centuries and is estimated to have conferred about a 20% reproductive advantage, countering the idea that early domestication was driven primarily by coat color.