In the classical model derived from experiments in the chick wing, the antero-posterior (thumb-little finger) pattern of digits arises in response to a concentration gradient of Sonic hedgehog (Shh) protein produced by the polarizing region - a specialized group of cells located at the posterior margin of the early limb bud. In the mouse, however, it has been demonstrated that the two most posterior of the five digits are derived entirely from the polarizing region by proliferation without the requirement of Shh diffusion. To understand the contribution and significance that polarizing region cell proliferation has in forming different digit patterns, we grafted polarizing regions from a transgenic chicken line stably expressing Green Fluorescent Protein (GFP) into normal wing buds (three digits), or leg buds (four digits). We will describe how these fate-maps behave when either Shh signalling is dampened, or proliferation is inhibited. We will present a model outlining our findings, highlighting the evolutionary implications.
|Pages (from-to)||S211-S212, abstract 12-P056|
|Journal||Mechanisms of Development|
|Issue number||Suppt. 1|
|Publication status||Published - 2009|
|Event||16th International Society of Developmental Biologists Congress 2009 - Edinburgh, United Kingdom|
Duration: 6 Sep 2009 → 10 Sep 2009