discredit about gills
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Answer:
The GOLT's basic tenet is that the surface area of the gills or ... To counter the tendency to discredit proposed hypotheses
Answer:
Gillis and his co-author Brian K. Hall provide evidence showing that in the development of the gill or branchial arches (a paired series of skeletal elements that support the gills and run down either side of the pharynx in fishes) and of the branchial rays (cartilaginous rods that articulate at their base with the gill arches in sharks and rays and protrude laterally from the gill arches), the common toolbox gene sonic hedgehog (Shh) establishes the anterior-posterior axis and the proliferative expansion of branchial endoskeletal progenitor cells. Those are the cells that give rise to the internal support system in vertebrates, composed of bone (in bony fishes and tetrapods) or cartilage (in sharks and rays).
What is the significance of their report? It is that precisely the same gene establishes the anterior-posterior axis in the tetrapod limb (in the human hand this is the axis from the thumb to the little finger) and promotes proliferation of the endosketal progenitor cells. This, as mentioned, supports a notion first proposed more than a century ago by the great German morphologist Carl Gegenbaur.