Anatomical features, scientists know, come and go. The animal kingdom is full of critters that have independently gained or lost similar features. Whales and snakes, for instance, have lost their legs. Winged flight evolved separately in birds, bats and pterosaurs at different times in evolutionary history.
Now, writing today (April 20, 2006) in the journal Nature, a team of scientists from the Howard Hughes Medical Institute (HHMI) at the University of Wisconsin-Madison, reveal the discovery of the molecular mechanisms that allow animals to switch genes on or off to gain or lose anatomical characteristics.
"Evolution can and does repeat itself," says Sean B. Carroll, a UW-Madison genetics professor and senior author of the new Nature report that describes how males of different fruit fly species have independently gained -- and repeatedly lost -- the wing spots that make them appealing to females.
"These spots have appeared and disappeared independently in different species at different times over the course of evolutionary history, and have been junked at least five times in one particular group," says Benjamin Prud’homme, a UW-Madison post-doctoral fellow working in Carroll’s lab and the lead author of the new study. "We have shown that each of these transitions corresponds with changes in how a certain gene is used."
The new study reveals how evolution occurs at the finest level of detail and explains the molecular mechanisms at work when animals lose or gain features. In the fruit fly, a gene known as "yellow" is responsible for the fly’s wing decoration.
"The gene is like a paintbrush," says Carroll. "But it needs instructions as to where to paint. Little switches embedded in DNA around the gene have the instructions. It is these switches that are evolving. The fly can lose a spot because of a very small change in his spot switch."
Known as "regulatory elements," the switches that govern gene activity are DNA sequences that act like toggles to turn genes on or off. Individual genes can have several switches, Carroll notes, each one devoted to controlling the gene in a different tissue or body part.
In the case of fruit flies, the changes in the switches’ activity are driven by the preferences of females. The flies meet on flowers and the male fly -- to put the female in the mood -- waves his wings and displays his conspicuous wing spots.
"Female preference is a strong force in the evolution of anatomy," explains Prud´homme. "This phenomenon -- sexual selection -- is all over the animal kingdom. It was one of Darwin’s great ideas."
Finding the same gene and the same processes at work -- molecular switch evolution -- in two distantly related species of fly is remarkable, according to Carroll, because it shows how and why evolution repeats itself.
"The funny thing is they came up with the same solution," Carroll says. "The big picture is that we are seeing the repetition of evolution -- in animals widely divergent in time and space -- at several key levels."
Sean B. Carroll | EurekAlert!
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy