PCA plot of all arrays. The results of the principal component analysis of all 44 arrays were used as input for the Birdseed2-based intensity calculation. The x-axis represents the first and the y-axis the second principal component based on the RAS values of all 909,622 SNPs represented on the array. Triangles correspond to the arrays of DNA-Pool 1 and squares to the arrays of DNA-Pool 2. Equally colored symbols indicate that the corresponding DNA-pools were processed by the same person.