Our lab combines elements of forward and reverse genetics, and predominantly uses histology and RNA and protein expression analytical techniques. Using these techniques, we determined that the somites produce signals that induce precocious maturation of the surface ectoderm on the flank, culminating in a mammary fate. We identified a molecular cascade involving Gli3 mediated transcription of FGF10 in the somites, and canonical Wnt signalling downstream of FGF10 mediated FGFR2b activation in the ectoderm. This cascade is required for induction of a mammary cell fate at the position of placode pair 3, which by position is very similar to the human breast. Reduced functioning of the human counterpart of this pathway may provide a molecular explanation of the ontogeny of Poland syndrome.