Figure 3. Effects of gene disruption on mandible and pelvic girdle shape.

In the scatterplots of the first and second principal components of (A) mandible landmark data and (B) pelvic girdle landmark data, black/red symbols are females, open/blue symbols are males, squares are homozygous wild-type, diamonds are heterozygotes and circles are homozygous Pappa2 disruption. To highlight the effects of disruption, symbols for homozygote knock-out females are red and those for homozygote knock-out males are blue. Outlines above the graph illustrate variation in shape measured by the first principal component, and represent extremes in shape (PC1 = −0.1 and 0.1) to facilitate visualization. Outlines to the right of the graph illustrate variation in the second principal component. Dots on the outlines indicate the location of landmarks. Note that analyses are carried out on the locations of landmarks, and outlines are drawn only to visualize changes in shape; outlines should therefore be interpreted with caution. Because of broken, damaged or missing bones, sample sizes were reduced compared to analyses of body mass, and a total of 61 mandibles and 71 pelvic girdles were analysed.