Jamess

I was wondering about how do you change patterning during embryo development to create zebrafish with lungs. I am thinking about swim bladder as a base candidate organ (as in lungfish) and basically, you have to have mesoderm and endoderm interactions. It is false and not true that we all have gilts during fetal development. So the next step in evolution has to be lungs after them. I am pretty sure, based on evolution which is lazy, that you would need only a few point mutations in genes promoting the development of lungs in the chick. Wnt, Bmp pathways, TgfB for branching. But how do you see that, what would we have to do? Let say that we have all the options available.