Gene expression was affected by lineage, sex, and stage.

<p>(A) Clustering dendrogram of individual microarray samples. The E11.5, E12.5, and E13.5 samples are represented by short, intermediate, and long bars, respectively. The dashed bars indicate XX samples, and the solid bars indicate XY samples. Ward's method with squared Euclidean distance as the distance metric was used. The arrays cluster primarily by lineage, and secondarily by sex and stage. (B) Analysis of the sources of variation confirmed that the primary source of variation is lineage, and secondarily sex and stage.