These beauties, the African Clawed frog xenopus laevis have donated their eggs to science. University of Tokyo scientists used the eggs to build olfactory sensors.
"The immature eggs were harvested and then injected with DNA from fruit flies, silk moths and diamond back moths, which stimulated the eggs to produce the olfactory sensors of these insects ....the eggs basically acted as a platform for the parts of the insect DNA that have been shown in the past to be responsible for detecting gases, odors, and pheromones."
Articles here and here
Photo: Tim Vickers Xenopus laevis