Figure 2: Chick wing polarizing region fate maps.
From: Insights into bird wing evolution and digit specification from polarizing region fate maps
(a) Gfp-expressing polarizing regions grafted in place of host (pos, posterior) polarizing regions contribute to the posterior margin of digit 4 (n=11/14). (b) Shh expression in donor wing bud 0 h and host wing bud 4 h after polarizing region replaced (n=3/3). (c) Cells derived from polarizing region seem to co-localize with digit 4 cartilage condensation in day 7 whole mounts (n=2/2). (d,e) Longitudinal (d, n=2/2, plane shown by dashed line in e) and transverse (e, n=2/2) section in situs showing Gfp expression in soft tissue adjacent to day 10 digit 4 cartilage. (f) Gfp-expressing polarizing regions grafted to anterior (ant) margins contribute to the posterior margin of duplicate (*) chick wing digit 4 (n=21/21). (g) Longitudinal section in situ showing Gfp expression in soft tissue adjacent to duplicate (*) day 10 digit 4 cartilage (n=3/3). (h,i) Gfp-expressing chick wing polarizing regions grafted in place of a chick leg polarizing region (h) and to the anterior margin of a chick leg bud (i) give rise to digits (n=7/10). (j,k) Longitudinal section in situ showing Gfp expression in soft tissue and cartilage of digit derived from chick wing polarizing region grafted to the posterior (j) or anterior (k) margin of a chick leg bud (n=2/2). Scale bars: a,f,I—1 mm; b,c—100 μm; d—50 μm (g,j,k—same scale); e—150 μm; h—750 μm.
