Figure 1

Principal component analysis of the gene expression matrix. (a) The first two principal components, explaining 35.0% and 34.7% of the observed variance, respectively, and (b) the next two principle components, explaining 9.5% and 3.3% of the variance, respectively. Round symbols represent females, squared symbols represent males, the colours represent the 5 maternal half-sib families. Ellipses and the grey area in panel b emphasize the clustering by developmental stage.