We were sitting next to the ocean in Newport, OR the other day when Amelia showed us a newspaper clipping of a two-faced cat aka a "Janus" cat. Named for the Roman god with two faces - Janus. This is where we get the name for our month "January" which makes sense since it was thought the two heads of this god were looking into the past and the future at the same time - like we look back at the year gone by and make resolution for the year to come on January one.
Looking into this condition I found that the likely cause of this is an over-expression of a gene dubbed "SHH" or Sonic hedgehog. I'm not kidding on the name - fruit-fly geneticists historically had a sense of humor in naming their knock-out flies.
Comprehending the mechanism of action of the SHH protein in development is an excellent exercise in seeing how there is no greater "plan" from God but rather an "apparent plan" that manifests because of our relatively complacent evolutionary era. There is nothing unethical about a genetic disorder. It is what it is and the affected either lives or dies. This cat was not cursed by God. Its existence is a window for mankind into one possibility of mutation. One out of a million might be useful. On a long enough timeline that one doesn't just become more likely but rather inevitable.
One of the coolest things I can think of in the age of you tube and Facebook is our collective ability to rapidly be aware of rare occurrences. This will not be the last cat in history to have this rare condition. What interests me is the subtle differences in expression of this gene from human to human as the SHH gene also regulates the organization of the human brain. There are clinical examples of babies born with the Janus condition who did not live. Thinking about this leads me to speculate that a viable two-faced human may have actually lived to adulthood at some point in history. Is such an individual responsible for the depictions of the Roman God Janus? We may never know. But a viable two-brained adult would be a marvel to have a game of chess with :)