Measuring three to 10 centimetres long, stickleback fish originated in the ocean but began populating freshwater lakes and streams following the last ice age. Over the past 20,000 years – a relatively short time span in evolutionary terms – freshwater sticklebacks have lost their bony lateral plates, or “armour,” in these new environments.
“Scientists have identified a mutant form of a gene, or allele, that prohibits the growth of armour,” says UBC Zoology PhD candidate Rowan Barrett. Found in fewer than one per cent of marine sticklebacks, this allele is very common in freshwater populations.
Barrett and co-authors UBC post-doctoral fellow Sean Rogers and Prof. Dolph Schluter set out to investigate whether the armour gene may have helped sticklebacks “invade” freshwater environments. They relocated 200 marine sticklebacks with the rare armour reduction allele to freshwater experimental ponds.
“By documenting the physical traits and genetic makeup of the offspring produced by these marine sticklebacks in freshwater, we were able to track how natural selection operates on this gene,” says Rogers.
“We found a significant increase in the frequency of this allele in their offspring, evidence that natural selection favours reduced armour in freshwater,” says Barrett.
Barrett and Rogers also found that offspring carrying the allele are significantly larger in size. “It leads us to believe that the genetic expression is also tied to increased growth rate,” says Barrett.
“If the fish aren’t expending resources growing bones – which may be significantly more difficult in freshwater due to its lack of ions – they can devote more energy to increasing biomass,” says Barrett. “This in turn allows them to breed earlier and improves over-winter survival rate.”
Celebrating its 150th anniversary this week, Darwin’s first publication of his natural selection theory proposed that challenging environments would lead to a struggle for existence, or “survival of the fittest.” Since then, scientists have advanced the theory by contributing an understanding of how genes affect evolution.
“This study provides further evidence for Darwin’s theory of natural selection by showing that environmental conditions can directly impact genes controlling physical traits that affect the survival of species,” says Barrett.
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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
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22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy