Genome-Wide Analysis of the World's Sheep Breeds Reveals High Levels of Historic Mixture and Strong Recent Selection
Principal component (PC) analysis of genetic distance was performed using a subset of 20,279 SNP identified by LD-based SNP pruning. Heat strips for each of the first 10 PCs are shown for 74 breeds (top panel). The PC value for each animal was normalised to range from 0 to 1 and visualised as a colour spectrum from green (0) to red (1). Plots for PC1 and 2 (bottom left) and PC1 and 3 (bottom right) each revealed the clustering of 1,612 animals selected to balance the number of animals across breeds. Individuals are colour coded to represent their geographical origin.