I’m told by Jim Sanderson and Patrick Watson (Small Wild Cats) that in 2005 scientists found that cats lack one of a pair of proteins which are needed to sense sweetness. And the missing protein was because of the loss of a part of a chromosome or sequence of DNA in a gene. This part was deleted during the cat’s evolution. I would regard that as a genetic mutation.
The deletion of this bit of DNA resulted in one of the proteins that enables the reception of sweetness from working (being expressed).
All cat share the same trait which indicates that this mutation occurred very early on in the evolution of the cat family. And interestingly, it may be the case that this mutation resulted in cats becoming strict carnivores i.e. hypercarnivores because it meant that they ignored plants entirely. Nice thought that.
To add some detail to the above, cats lack the taste receptors known as “T1R2” and “T1R3,” which are responsible for detecting sweetness. Without these receptors they simply can’t taste sweetness.
And therefore, they possess taste receptors which are specifically tuned up to appreciate the flavours found in meat. Or we should call this ‘flesh’ because the wild cats eat flesh and the word “meat” is a human way of trying to forget the fact that we eat the flesh of animals. We don’t like to think about that.
Cats have taste receptors for sourness and bitterness which helps them to pick out toxins or spoiled food. It is believed that this is a protective mechanism because many toxic substances are better.