, manipulating "Hox" genes does little to solve the problem of generating novel functional biostructures, for making large changes in phenotype are rarely beneficial. Hox gene mutations may be a more simple mechanism for generating large change, but they also do not escape the problem of the "hopeful monster":"The drawback for scientists is that nature's shrewd economy conceals enormous complexity. Researchers are finding evidence that the Hox genes and the non-Hox homeobox genes are not independent agents but members of vast genetic networks that connect hundreds, perhaps thousands, of other genes. Change one component, and myriad others will change as well--and not necessarily for the better. Thus dreams of tinkering with nature's toolbox to bring to life what scientists call a "hopeful monster"- such as a fish with feet--are likely to remain elusive."Furthermore, many biologists forget when invoking Hox gene mutations that Hox genes can only re-arrange parts which are already there--they cannot create truly novel structures