Figure 6.
Correlation matrix of nine water maze (WMZ) traits from Milhaud and colleagues (2002). Traits covary well, and it is therefore useful to statistically represent some of these traits by a principal component (see bottom of figure). In this case a synthetic PC trait can explain over 75% of the total phenotypic variance among genotypes of mice. Synthetic traits can be used like all other standard traits for mapping and behavioral analysis.