PARIS: The monarch butterfly’s annual migration from North America to Mexico, a spectacular event at risk of disappearing forever, is the result of a single, millions-year old gene, biologists said Wednesday. Analysis of the insect’s long-guarded genetic secrets has changed what we knew about its history, migration and distinctive bright orange-and-black wing colouring,  hey wrote in the journal Nature. “Prior to our work, monarch migration was thought by some to be a very recent phenomenon, but we have shown that it evolved millions of years ago,” study co-author Marcus Kronforst told AFP of the findings that he said “overturn past thinking about monarch butterflies”. “I believe this raises the stakes considerably when we consider that we may be witnessing the end of an amazing biological phenomenon that these little insects have been carrying out every year for the past two million-plus years.”–AFP