Population structure and signature of selection for body size in some Iranian and exotic horse breeds.

This research article explores the genetic diversity of various Iranian and exotic horse breeds, with particular focus on genes and biological pathways relating to body size, which may impact the horses’ performance.

Objective and Methods

• The study’s objective was to identify genomic regions that show signs of adaptation selection, along with candidate genes and biological pathways related to body size in various Iranian and exotic horse breeds, which could possibly influence the horses’ performance.
• The researchers collected samples from three native Iranian horse breeds (the Caspian pony, Turkmen, and Kurdish) and three foreign breeds (the Fell pony, Arabian, and Akhal-Teke) from England, the Middle East, and Turkmenistan respectively.
• Each breed’s genotyping data was gathered, with 50K SNPs for the exotic breeds and 70K SNPs for the Iranian breeds.
• A Discriminant Analysis of Principal Components (DAPC) exploration was then conducted to understand the population structure and genetic differentiation of the breeds.

Results and Findings

• Analysis of the population structure revealed a clear distinction between pony and light horse breeds. The Akhal-Teke and Turkmen breeds clustered together while the Fell ponies formed a separate group.
• Using FLK and hapFLK tests, researchers were able to identify 124 and 127 candidate genes under selection in the breeds respectively.
• Many of these identified genes were linked directly to body size traits. These traits centered around bone mineralization, osteoblast differentiation, growth factor signaling, and tissue development.
• The researchers also discovered certain novel genes that had not been previously reported in these types of studies on horses. These include SAMD7, DEUP12, SPARC1, IBSP, PLAAT1, MEPE, and SPP1, broadening understanding in the field of equine morphology.

Conclusion

• Overall, the research findings demonstrate selection signatures linked to genes influencing body size and development and unveiled several novel candidates. This builds on and deepens understanding of equine morphology and horse genetics.
• The findings encourage further investigation on a larger scale using a more extensive sample size.