in situ hybridisation to avian hindbrain

Hindbrains from two 3 day old avian embryos showing the expression of the homeobox gene Hoxb-1 as viewed from above. At this stage of development the hindbrain is made up of repeating structures called rhombomeres. On the right, in a normal hindbrain, Hoxb-1 is switched on in rhombomere 4. On the left, part of rhombomere 4 from a donor embryo has been grafted in front of the host's rhombomere 4. Hoxb-1 remains switched on in the grafted rhombomere despite its new position.