Researchers in the US and Britain have pinpointed a peculiarity in feline DNA: cats never develop the sweetness receptors that exist on the tongues of other mammals.
Sweet compounds, including sugars and artificial sweeteners, are recognized by a special taste bud receptor composed of the products of two genes. The authors found that in cats, one of these genes is not functional and is not expressed. (It is called a pseudogene.) Because the sweet receptor cannot be formed, the cat cannot taste sweet stimuli.
The results of this research are published today in PLoS Genetics.