Genetic variation within the Merino sheep breed: analysis of closely related populations using microsatellites

Genetic relationships among six populations of Merino sheep were investigat ed using microsatellites. The history of the six populations is relatively well documented, with all being derived from the Spanish Merino breed withi n the last 400 years. Genetic variation was highest amongst the Spanish and Portuguese populations, although the preservation of genetic diversity wit hin the other populations was high. By a variety of different statistical t ests the French Mutton, German Mutton and New Zealand Merino populations co uld be differentiated from each other and the Iberian Merinos, indicating t hat microsatellites are able to track relatively recent changes in the popu lation structure of sheep breeds. The dendrograms constructed on the basis of microsatellite allelic frequencies showed that populations that have sha red selection criteria (meat vs. weal) tend to cluster together.