Notably, while the overall coloboma phenotype was variable in intensity in the TGFβ2 single mutants from a mixed breeding background (e.g. figure 1b, electronic supplementary material, figure S1A, B), we could only detect very subtle forms of coloboma in TGFβ2 single mutants from a sole background (figure 1d, figure 1c as control). This evidence concerns the gene TGFB2 and coloboma.