Great question! The simple answer is that individuals don't evolve. Rather, it's populations that evolve.
Lykoi are still a sub-species of Felis silvestris catus(domestic house cat). Sub-species means they can still mate and produce viable offspring with other breeds. If this mutation were truly beneficial, it would take thousands of years for it to spread and become dominate in the population. And Felis silvestris catus would STILL BE Felis silvestris catus. In order for it to become its own species it would have to be so different it couldn't mate with domestic house cats anymore.
A good anology for this is language. The French language is derived from Latin. Over a long period of time Latin evolved into French. But there was no Latin speaking mother who gave birth to a French speaking son. There was no one day everyone stopped speaking Latin and started speaking French. It was a gradual evolution over several generations throughout the entire population. Language is transient. Its always changing. Just like genetics.
For more information on this sort of thing it would be helpful to do a little research on Allele Frequencies and Ring Species. Hope that answered your question. If you have anymore feel free to ask :)