Selection at the GSDMC locus in horses and its implications for human mobility

Area of Science:

• Animal Genetics
• Archaeology
• Evolutionary Biology

Background:

• Horse domestication profoundly impacted human history, yet the genetic basis for key traits remains largely unknown.
• Understanding the evolutionary trajectory of horse domestication provides insights into human-animal co-evolution.

Purpose of the Study:

• To identify genetic signatures of selection associated with horse domestication.
• To pinpoint the timing and specific genes involved in the early stages of horse domestication.

Main Methods:

• Genome-wide analysis of an extensive horse genome time series.
• Selection signature scans at 266 genetic markers linked to important traits.

Main Results:

• A significant positive selection signature was identified at the ZFPM1 gene ~5000 years ago, suggesting early selection for tamability.
• Intensive selection on GSDMC began ~4750 years ago, coinciding with the domestication bottleneck, with regulatory variants reaching high frequency by ~4150 years ago.
• GSDMC genotypes are associated with horse body conformation and, in mice, with spinal anatomy, motor coordination, and muscular strength.

Conclusions:

• Taming, influenced by ZFPM1, was likely an early step in horse domestication.
• Selection on standing variation in GSDMC was critical for developing horses with enhanced mobility, facilitating their integration into human societies ~4200 years ago.