Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic tweak gave yellow fever mosquitoes a nose for human odor

13.11.2014

One of the world's deadliest mosquitoes sustains its taste for human blood thanks in part to a genetic tweak that makes it more sensitive to human odor, according to new research.

Researchers report in the journal Nature that the yellow fever mosquito contains a version of an odor-detecting gene in its antennae that is highly attuned to sulcatone, a compound prevalent in human odor. The researchers found that the gene, AaegOr4, is more abundant and more sensitive in the human-preferring "domestic" form of the yellow fever mosquito than in its ancestral "forest" form that prefers the blood of non-human animals.


Researchers report that the yellow fever mosquito sustains its taste for human blood thanks in part to a genetic tweak that makes it more sensitive to human odor. The human-preferring 'domestic' form of the mosquito (right) contains a version of the odor-detecting gene AaegOr4 in its antennae that is highly attuned to sulcatone, a compound prevalent in human odor. The researchers found that this gene is more abundant and more sensitive in the domestic form than in its ancestral 'forest' form (left), which prefers the blood of non-human animals.

Credit: Carolyn McBride, Department of Ecology and Evolutionary Biology and the Princeton Neuroscience Institute

The research provides a rare glimpse at the genetic changes that cause behaviors to evolve, explained first author Carolyn "Lindy" McBride, an assistant professor in Princeton University's Department of Ecology and Evolutionary Biology and the Princeton Neuroscience Institute who conducted the work as a postdoctoral researcher at the Rockefeller University. Uncovering the genetic basis of changes in behavior can help us understand the neural pathways that carry out that behavior, McBride said.

The research also could help in developing better ways to stem the yellow fever mosquito's appetite for humans, McBride said. The yellow fever mosquito is found in tropical and subtropical areas worldwide and is the principal carrier of yellow fever, the measles-like dengue fever, and the painful infection known as chikungunya.

Yellow fever annually kills tens of thousands of people worldwide, primarily in Africa, while dengue fever infects hundreds of millions. The research also suggests a possible genetic root for human preference in other mosquitoes, such as malaria mosquitoes, although that species is genetically very different from the yellow fever mosquito.

"The more we know about the genes and compounds that help mosquitoes target us, the better chance we have of manipulating their response to our odor" McBride said, adding that scent is not the only driver of mosquito behavior, but it is a predominant factor.

The researchers first conducted a three-part series of experiments to establish the domestic yellow fever mosquito's preference for human scent. Forest and domestic mosquitoes were put into a large cage and allowed to bite either a guinea pig or a researcher's arm.

Then the mosquitoes were allowed to choose between streams of air that had passed over a guinea pig or human arm. Finally, to rule out general mosquito attractants such as exhaled carbon dioxide, mosquitoes were allowed to choose between the scent of nylon sleeves that had been in contact with a human or a guinea pig.

In all three cases, the domestic form of the yellow fever mosquito showed a strong preference for human scent, while the forest form primarily chose the guinea pig. Although domestic mosquitoes would sometimes go for the guinea pig, it happened very rarely, McBride said.

McBride and colleagues then decided to look for differences in the mosquitoes' antennae, which are equivalent to a human's nose. They interbred domestic and forest mosquitoes, then interbred their offspring to create a second hybrid generation. The genomes of these second-generation hybrids were so completely reshuffled that when the researchers compared the antennae of the human- and guinea pig-preferring individuals they expected to see only genetic differences linked directly to behavior, McBride said.

The researchers found 14 genes that differed between human- and guinea pig-preferring hybrids -- two of them were the odorant receptors Or4 and Or103. Choosing to follow up on Or4, the researchers implanted the gene into fruit-fly neurons. They found that the neurons exhibited a burst of activity when exposed to sulcatone, but no change when exposed to guinea pig odors. McBride plans to further study Or103 and other genes that could be linked to host preference at Princeton.

This work provides insight into how the domestic form of the yellow fever mosquito evolved from its animal-loving ancestor into a human-biting specialist, McBride said. "At least one of the things that happened is a retuning of the ways odors are detected by the antennae," she said. "We don't yet know whether there are also differences in how odor information is interpreted by the brain."

The paper, "Evolution of mosquito preference for humans linked to an odorant receptor," was published by Nature Nov. 13, 2014.

This work was supported in part by the National Institutes of Health (NIDCD grant no. DC012069; NIAID grant no. HHSN272200900039C; and NCATS CTSA award no. 5UL1TR000043); the Swedish Research Council and the Swedish University of Agricultural Science's Insect Chemical Ecology, Ethology and Evolution initiative; and the Howard Hughes Medical Institute.

Morgan Kelly | EurekAlert!

Further reports about: Genetic antennae differences fever genes mosquito mosquitoes nose yellow fever mosquito

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>