Japanese researches have produced a frog that is transparent, thus making dissection unnecessary. However, it's still exploitative and cruel.
Even though most schools and institutions still insist on using animal dissection for research purposes, there are actually kind alternatives such as computer models. Students can learn everything they need to without having to cut open an animal. (PETA2 has compiled a longer list of alternatives here)
Genetically modifying frogs to be transparent is exploitative in that we're using them for our own selfish wants. Do we need see-through amphibians? No. Like I said above, there are alternatives that wouldn't require a living creature at all.