Hold on there Chicken Little. First, even the article you quoted states that every major vertebrate group (insects, fish, birds, reptiles, anphibians, snakes, etc) do this. The only type that hasn't been found to do this are mammals.

Second: One shark in captivity does not make a "trend", nor should something already known to occur in nature qualify as "disturbing" (Ironraven excluded ;)).

Three: As for this being seen only in captive animals, think about this logically for a second. How could we see this in nature? We don't DNA match every creature's birth. It could be happening all the time in nature, We just wouldn't notice.

Four: The article also states that this is may be a way for creatures to adapt to harsh conditions. This suggests it is a trait that has evolved in animals. In other words, it has happened many times before. Life does not spontaneously mutate to to develop new traits in response to it's environment. Life mutates randomly and if this new trait helps it survive then the trait is passed on.

Maybe you should hold off reading the news for a while...

-Blast