The Gorgeous Tail of Peacock
A New Answer to Darwin’s Puzzle
Abstract: This paper talks about the recent research of the regulation and evolution of a genetic switch controlling sexually dimorphic traits in drosophila, which is a new answer to Darwin’s puzzle on the gorgeous tail of male peacock.
Keywords: Tail of peacock, genetic switch, drosophila
When it comes to a peacock, it always occurs to us the image of its brilliant blue or green plumage, and long modified back feathers that are marked with iridescent eyelike spots and that can be spread in a fanlike form, which is actually the characteristic of a male peafowl. However, to Charles Darwin, this gorgeous tail of the peacock wastes large amounts of energy and makes him an easy prey to his natural enemy. According to Darwin’s natural selection theory, such an adverse trait should have been eliminated through evolution. But why are those male peacocks and many other species of cock birds developing a second sex characteristic that is dangerous for their lives? It was really a big headache for Darwin and his followers.
Recently, researchers in Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin, have figured out the answer of the puzzle why evolution chooses such a male characteristic. They find a simple genetic switch controlling sexually dimorphic traits in drosophila, and how is the genetic switch evolving. Also, their research results explain female peacocks choose mates with beautiful tails, or in the case of lions, with big, bushy black manes.
The research team led by Sean Carroll, molecular biologist from University of Wisconsin, describes the control and evolution of one of genetic circuit in drosophila －－this genetic circuit help to modify the male drosophila’s abdomen, and this work also shows how the same genetic circuit in female drosophila’s body repress this modification. Carroll said: “it is not why but how that our...