Fig. 6. A pair-wise comparison of Nkx2.5 mesodermal expression areas in Fgf8-treated embryos. Each sample represented on the x-axis is taken from one embryo, with the Fgf8-treated side shaded in blue and the contralateral control side shaded in red. The y-axis is a measurement of the mesodermal area expressing Nkx2.5 from a representative section (see Materials and Methods). In all embryos, the Nkx2.5-expressing area was greater on the Fgf8-treated side, with an average increase of 1.5-fold. Statistical analysis using Student’s two tailed t-test gave a P value of 0.008 (df=12).