Where Do the Cold Blood Breeds Come from and Where Does Polysaccharide Storage Myopathy Fit in?

Myopathy associated with a gain‐of‐ function mutation in the GYS1 gene is known in Q uarter H orses and cold blood breeds. The mutation occurred between the collapse of the R oman E mpire (500 AD ) and the upsurge of C arolinian R eign (800 AD ). The aim of this review is to reconstruct the development of the cold blood (brachimorph) breeds in E urope using existing literature. Methods Literature review Results Although archaeological evidence indicates the existence of a mesomorph horse ( C ob) type in the early I ron Age, real cold blood breeding only started after 1750. The demand for draught power in the early Industrial Revolution resulted in a large population of cold bloods from 1850 onwards. In R oman times, the huge ugly horses from Thrace were known as “easy keepers” and Ardennes might have been the first land races carrying the GYS1 mutation. Hunnish horses might have contributed to the prototype cold bloods as well. With mtDNA , Y ‐chromosome polymorphism, satellite markers and SNP genotyping some indication from where ancestors of particular breeds originate was obtained. Most phylogenetic trees place cold blood breeds, including Fell ponies, Haflinger and Friesian in a clearly different cluster than ponies, saddle horses and T horoughbreds. Fjords and Mongolian horses are in neighbouring clusters. Since the last 200 years, genetic bottlenecks and the popular sire phenomenon could have caused high GYS1   H allele frequencies in many continental cold blood breeds. Conclusions Cold blood breeds and the GYS1 mutation likely trace back to the mesomorph tough, easily satisfied horse types from E astern E urope and central A sia. Ethical Animal Research No animals were used in the study. Sources of funding:  none. Competing interests:  none.