News / Health

Scientists Use Genetic Technique to Control Malaria Mosquito

Adult mosquitos with glowing eyes that indicate they have been successfully genetically transformed are seen through a fluorescence microscope at the University of Maryland Biotechnology Institute's Insect Transformation Facility in Rockville, Md., June 3
Adult mosquitos with glowing eyes that indicate they have been successfully genetically transformed are seen through a fluorescence microscope at the University of Maryland Biotechnology Institute's Insect Transformation Facility in Rockville, Md., June 3
Jessica Berman

An international team of scientists has developed a way to genetically modify the malaria mosquito so that it would be unable to transmit the disease to humans. Researchers say the method eventually might be used to control large populations of mosquitoes by releasing a small number of modified insects into the wild that could breed the trait into ensuing generations.  

For the past 10 years, researchers have been attempting in the laboratory to biologically alter the malaria mosquito, known as Anopheles gambiae, so it can’t breed and spread the parasitic illness, as well as several other diseases.  

Malaria affects more than 300 million people around the world every year, killing nearly 800,000 people, most of them children.

The goal of the latest research, according to parasitologist Andrea Crisanti of Imperial College London, is to control the female mosquito - which spreads the disease by biting humans - without having to resort to chemical pesticides, which can be harmful to people and the environment.  

“The path that we have chosen is to develop mosquitos that are eventually resistant to malaria and they spread that resistance gene to local populations [of mosquitoes]. So, in principal, they do the job for us,” said Crisanti.

Crisanti led a team of British, U.S. and Japanese researchers that inserted a unique segment of genetic material, or DNA, into the chromosomes of the malaria mosquito.  

The DNA segment, known as a “selfish gene,” produces an enzyme that inactivates specific genes and replaces them with copies of itself.

In laboratory experiments, the researchers mated a small number of male mosquitoes carrying the selfish gene with female insects bred to carry a fluorescence gene that made them glow green for easy identification.

At the start of the experiment, 99 percent of the mosquitoes had the green tag. Just one percent had the selfish gene.

Within a dozen generations, Crisanti said, more than half of the Anopheles mosquitoes lacked the green tag, after acquiring the male mosquitoes’ selfish gene.

“So in this way, generation after generation of the progeny carries the genetic modification and this has increased exponentially. And in a span of 12 generations, which is more or less the time span of the rainy season of a malaria endemic country.”

The results are what are called a proof of principle - scientists have showed it is possible to use genetic engineering to control populations of malaria mosquitoes.

Previous control efforts have involved sterilizing male mosquitoes with radiation and releasing millions of them to mate with females in the wild so they cannot produce fertile offspring. But they have not worked very well. Experts say the female Anopheles prefers to breed with wild male mosquitoes.

Chrisanti said the research team’s goal now is to work on specific Anopholes genes that are essential to its transmission of the malaria parasite.  The team already has identified 10 candidate genes, including an odor-recognition gene that helps mosquitoes locate their human hosts, and a gene that permits the malaria parasite to enter the mosquito’s salivary gland.

An article on genetic manipulation of the Anopheles mosquito for malaria control is published this week in the journal Nature.

You May Like

Video Five Patients Given Experimental Ebola Drug Said To Be Improving

Experimental drugs have been tried on six people: three Westerners and now, three African pyhysicians More

Video In Ukraine, Fear and Distrust Remain Where Fighting has Stopped

As Ukrainian military reclaims control of eastern cities residents rebuild their lives, but many say everyone is being treated with suspicion More

Video In Rural Kenya, Pressure Builds Against Female Circumcision

Girls learn to object; FGM practitioners face penalties from jail sentences to stiff fines More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Five Patients Given Experimental Ebola Drug Said to Be Improvingi
X
Carol Pearson
August 19, 2014 11:43 PM
The World Health Organization has approved the use of experimental treatments for Ebola patients in West Africa. The Ebola outbreak there is unprecedented, the disease deadly. The number of people who have died from Ebola has surpassed 1,200. VOA's Carol Pearson reports on the ethical considerations of allowing experimental drugs to be used.
Video

Video Five Patients Given Experimental Ebola Drug Said to Be Improving

The World Health Organization has approved the use of experimental treatments for Ebola patients in West Africa. The Ebola outbreak there is unprecedented, the disease deadly. The number of people who have died from Ebola has surpassed 1,200. VOA's Carol Pearson reports on the ethical considerations of allowing experimental drugs to be used.
Video

Video In Ukraine, Fear and Distrust Remain Where Fighting has Stopped

As the Ukrainian military reclaims control of eastern cities from pro-Russian separatists, residents are getting a chance to rebuild their lives. VOA's Gabe Joselow reports from the town of Kramatorsk in Donetsk province, where a sense of fear is still in the air, and distrust of the government in Kyiv still runs deep.
Video

Video China Targets Overseas Assets of Corrupt Officials

As China presses forward with its anti-graft effort, authorities are targeting corrupt officials who have sent family members and assets overseas. The efforts have stirred up a debate at home on exactly how many officials take that route and how likely it is they will be caught. Rebecca Valli has this report.
Video

Video Leading The Fight Against Islamic State, Kurds Question Iraqi Future

Western countries including the United States have begun arming the Kurdish Peshmerga forces in northern Iraq to aid their battle against extremist Sunni militants from the Islamic State. But there are concerns that a heavily-armed Kurdistan Regional Government, or KRG, might seek to declare independence and cause the break-up of the Iraqi state. As Henry Ridgwell reports from London, the KRG says it will only seek greater autonomy from Baghdad.
Video

Video In Rural Kenya, Pressure Builds Against Female Circumcision

In some Kenyan communities, female genital mutilation remains a rite of passage. But activists are pushing back, with education for girls and with threats of punishment those who perform the circumcision. Mohammed Yusuf looks at the practice in the rural eastern community of Tharaka-Nithi.
Video

Video For Obama, Racial Violence is Personal Issue

The racial violence in the St. Louis suburb of Ferguson is presenting U.S. President Barack Obama with an issue to which he has a deep personal connection. To many Americans, Obama's election as America's first black president marked a turning point in race relations in the United States, and Obama has made ending the violence a policy priority. On Monday he issued a new call for calm and understanding. Luis Ramirez reports from the White House.
Video

Video Clinton-Obama Relationship Could Impact 2016 Election

President Barack Obama and former Secretary of State Hillary Clinton have a long and complicated relationship. That relationship took another turn recently when Clinton criticized the president’s foreign policy. VOA National Correspondent Jim Malone reports there is renewed attention on the Clinton-Obama relationship as Hillary Clinton considers running for
Video

Video Iran Looks to Maintain Influence in Baghdad With New Shia PM

Washington and Tehran share the goal of stopping Syrian-based militants in Iraq. But experts say it's Iran, not the United States, that will most influence how the new government in Baghdad approaches internal reforms and the war in Syria. VOA State Department Correspondent Scott Stearns has the story.

AppleAndroid