Comparative genetic diversity in a sample of pony breeds from the UK and North America: A case study in the conservation of global genetic resources

Most species exist as subdivided ex situ daughter population(s) derived from a single original group of individuals. Such subdivision occurs for many reasons both natural and manmade. Traditional British and Irish pony breeds were introduced to North America (USA and Canada) within the last 150 years and subsequently equivalent breed societies were established. We have analysed selected UK and North American equivalent pony populations as a case study for understanding the relationship between putative source and derived sub-populations. Diversity was measured using mitochondrial DNA and a panel of microsatellite markers. Genetic signatures differed between the North American sub-populations according to historical management processes. Founder effect and stochastic drift was apparent, particularly pronounced in some breeds, with evidence of admixture of imported mares of different North American breeds.