NEWS : TECH (NFPC)

Old Genes Make New, Giant-Headed Ants

Every animal carries a record of its past in its genes -- sometimes teeth show up in birds and vestigial limbs on snakes and whales. Ants are no exception. What if that potential could be tapped? And what brings it out?

That’s what a group of scientists at McGill University thought when they ran into a colony of ants on Long Island. A colony of ants known as Pheidole morrisi (more commonly called big-headed ants) had members we call soldiers with really outsized heads and bodies. These were called “super soldiers.”

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Pheidole, like many other ant species, are divided into castes, such as workers, queens and soldiers. Different foods are given to them when they are larvae, which triggers hormones that determine which caste the ant grows up to be.

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Super soldiers occur naturally in some species of Pheidole in the southwestern United States and Mexico. But those living in upstate New York aren’t supposed to have the big heads. Ants are a pretty diverse lot and there are more than 1,100 species within even the Pheidole genus. But only eight of them naturally produce the super soldiers.

Biology professor Ehab Abouheif and PhD student Rajee Rajakumar wondered if the genes that build super soldiers were present in the Long Island ants all along, but were just waiting for some environmental factor to bring them out. The scientists first went to Arizona and collected two other species of ant in the same genus, Pheidole rhea and Pheidole obtusospinosa, which both have a subclass of super soldiers. They then observed how those two species developed their super soliders.

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Next, the scientists gave the young Long Island ants juvenile hormones at certain specific points in their development. In the Pheidole morrisi they got the super-soldier ants, which showed that the potential was always there. It just needed something to bring it out. One interesting phenomenon was the super soldiers had wing buds, which their cousins from Arizona did not. Many ant species develop wings as part of their development and ants and wasps share a common ancestor. The procedure worked in three different species of Pheidole, even though all three were separated by thousands of miles and millions of years of evolution.

Previously, few biologists thought such ancestral traits were important. They were just leftovers like the stuff in your attic. This shows that when necessary, nature has a “tool kit” that it can use to create big morphological changes -- some of them new.

Via: McGill University

Image: Alexander Wild

 

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Justin Bieber a Dad? How a DNA Test Can Tell

Is Justin Bieber a father? That question is being asked as part of a lawsuit involving 20-year-old Mariah Yeater who claims that Bieber fathered her now three-month-old son. A definite yes or no answer hinges on the results of a paternity DNA test. Such a test analyzes up to 18 different genetic locations called anonymous non-coding regions on a person's genome. Every child gets his or her genes from both parents, so the son in this case will have to be tested along with Yeater and Bieber.

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It's not hard to get DNA to work with. A cheek swab is enough, as there are loads of cells that have nuclei containing DNA; extracting blood samples is another method.

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After obtaining the sample, a lab technician duplicates the relevant parts of the DNA. "There are specific regions that are helpful," Dr. Michael Baird, chief scientist at the DNA DIsgnostic Center, told Discovery News. His lab lab has does testing for parentage -- and has done so for a number of celebrities such as Anna Nicole Smith. "The regions we look at are the same ones used in forensic analysis," he said.

The DNA is tagged with molecules that fluoresce and is drawn up through a narrow tube, where different parts separate according to their weight. When they emerge from the tube they are hit with a laser light. The way the DNA fluoresces gives a pattern of peaks on a graph. Next, a scientist will compare patterns of peaks produced from the child's DNA to the patterns produced by results from the mother's and father's DNA test. The test examines up to 18 regions of the DNA. In each region, genes from the parents are in pairs, each component of which is called an allele.

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If almost all of the 18 alleles match up, then the man is considered to the be father. If three or more do not match up, then it’s almost certain that the man is not the father. However, if a lot of other markers are the same, one might look for a close male relative, such as a father or brother (Bieber has half-siblings, but his younger brother is in grade school).

Is there anything that can mess up a DNA test? Baird said there are some very rare conditions under which a DNA test can be “wrong.” If Bieber had leukemia and had gotten a bone marrow transplant, the DNA in his blood would show the markers from the donor. "We had one guy come in and his brother was a [bone marrow] donor," he said. Even a cheek swab might pick that up, though it doesn't happen often.

It’s also possible to have mutations, in which one or more of the alleles in the child differs form the parent. Two mismatched alleles occur about one in 500 times. But labs will often simply discard a single allele that doesn't match if all the others do.

The rarest of all cases is chimerism, in which a person has two sets of DNA sequences. There was a case in 2006 in which DNA tests results showed a woman wasn’t the mother of her children, when it fact it was later determined she was. But chimerism is so rare that Baird said he has seen only one case of it in nearly a decade at DDC.

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Networking Website Matches People by Gut Bacteria

eHarmony says they match you according to your personality and Facebook lets you connect with others according to common interests. MyMicrobes wants to match you according to your gut bacteria.

A non-profit operation, MyMicrobes is asking people to sign up and get their gut bacteria sequenced. Yes, you have to provide a stool sample, but you can also use the site to share your stories of digestive distress.

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This sounds like an opener to comedy skit, but there is a serious purpose. The research team is part of the Metagenomics of the Human Intestinal Tract (MetaHIT) Consortium. They published a paper in Nature that says people seem to fall into three "enterotypes" -- basically three categories of gut bacteria. It's rather like dividing the world into different biomes or habitats.

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What makes this important? Your gut bacteria respond to different drugs or diets. Finding a way to classify the kind of gut bacteria you have -- essentially figuring out what is "normal" for a given type of person -- will go a long way to helping diagnose problems. And those bacteria are important. They perform many functions that people need, extracting useful nutrients such as vitamins.

People certainly do want answers. Peer Bork, a biochemist at the European Molecular Biology Laboratory and a co-founder of the site told Nature he got the idea for MyMicrobes after getting nearly 100 emails from people concerned about their digestive problems. Plainly people are seeking answers.

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Hence MyMicrobes. To join up you pay $2,100, which seems steep -- Facebook is free, after all -- but it covers the cost of sequencing the genomes of the critters in your guts. Members get a stool-sample kit. The sample gets sent to a lab in Paris, where the DNA is extracted. The DNA goes to Bork's lab in Germany.

There are about 100 participants so far, and the researchers' estimate is that they need about 5,000 to perform more meaningful studies. It's possible gut bacteria might show responses to non-digestie ailments as well. In the small sample that was cited in the Nature paper there were 12 genes in the gut bacteria that correlated well with age, for instance. 

Via Nature.

Image: Wikimedia Commons via National Institutes of Health

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Virtual Lab Rats to Assist in Disease Study

Despite all their rage, lab rats are still just rats in a cage, right? Well, not any more. Thanks to computational biologist, Daniel Beard, the cage door will be somewhat opened, as he and his team has found a new breed to study -- virtual rats.

Beard and his colleagues at the Medical College of Wisconsin in Milwaukee will be studying integrated data sets of rat physiology to better understand how genes and environmental factors lead to disease.

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“We are working toward the grand challenge of biomedical research: understanding the complex interplay between physiological, genetic and environmental factors,” says Beard in a news release from the National Institute of General Medical Sciences.

Dubbing his project the "Virtual Physiological Rat," Beard hopes to glean new insight on human diseases like high blood pressure and heart failure. Live lab rats have been extensively used to study cardiovascular disease, but have been unreliable in showing how multiple genes and environmental conditions factor in to the cause of disease, primarily because these diseases can't be attributed to a single gene or lifestyle choice.

Therefore, to better their analysis and sharpen their hypotheses, Beard and his team will develop computer simulations of healthy rats, that is, after closely studying the healthy hearts, kidneys, skeletal muscles and blood vessels of live rats.

Beard ultimately hopes the "Virtual Physiological Rat" will help predict the rat's state of cardiovascular health by providing a more sophisticated database to compare a rat's genes with its molecular functions. 

"The Virtual Physiological Rat is a means to learn as much as we can from experiments,” says Beard. “I hope this will lead to much better, smarter, more efficient animal research.

[Via NewsWise]

Credit: G Robert Bishop/Getty Images

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Future Computers May Be DNA-Based

We've all heard our brain likened to a computer. But professor Jian-Jun Shu and his students at Nanyang Technical University are taking that comparison quite literally.

Shu and his team at the university's School of Mechanical and Aerospace Engineering have proposed a way to use DNA strands for computing operations.

Their article “DNA-Based Computing of Strategic Assignment Problems,” was recently published in the journal Physical Review Letters.

Shu points out that the human body performs computations that are naturally more faster than even the fastest silicon-based computer.

"No matter how fast tomorrow's conventional silicon-based computer can become," their article states,"in order to solve specific classes of problems, it may take the fastest silicon-based computer months or even years to process the calculations. This is mainly due to the serial computing nature of the conventional silicon-based computer."

So Shu and his students manipulated stands of DNA at the test-tube level. They found that they could fuse strands together, cut them and perform operations that would affect DNA's ability to store information.

“Silicon-based computing relies on a binary system,” Shu told PhysOrg.com. “With DNA-based computing, you can do more than have ones and zeroes. DNA is made up of A, G, C, T, which gives it more range. DNA-based computing has the potential to deal with fuzzy data, going beyond digital data.”

Shu says that DNA-based computing is currently in the most elementary stages and that more human manipulations must be done.

Credit: E.M. Pasieka/Science Photo Library/Corbis

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GM Mosquitoes Released in Malaysia to Reduce Dengue Spread

In late December, the Institute for Medical Research in Malaysia released about 6,000 genetically modified (GM) mosquitoes into the country's Eastern forests. They were designed by the U.K. company Oxitec as an experimental method to help prevent the spread of dengue fever, a mosquito-borne virus that impacts 50 to 100 million people every year and for which there is no cure. Last year, nearly 46,000 Malaysians caught the fever, which generally does not result in death, but causes headaches, fatigue, joint and muscle aches, nausea and vomiting.

All the mosquitoes were sterile male Aedes aegypti. Because female Aedes aegypti only breed once in a lifetime, introducing sterile males into a population is thought to be one way of greatly reducing the number of offspring and hence the number of dengue-carriers in the next generation. Actually, the males were not exactly sterile, but they carried a “lethal” gene that kills offspring early on; any survivors are not fit for reproduction. And since this was an experiment, the Institute simultaneously released 6,000 unmodified Aedes aegypti into the wild, with plans to track how many of each group survive.

Malaria-Proof Mosquito Created

Problem? Malaysians claim they were unaware that this trial was going on until late January, after it had ended. In the meantime, two Malaysian groups opposed to the use of GM mosquitoes appealed to the National Biosafety Board to cancel the study. They didn't know it was already happening.

What's wrong with using this biotechnology to try and reduce the risk of a raging illness among mosquito-infested areas? Some groups, including Greenpeace, worry that reducing the population of just one species will only make it easier for other species to proliferate in the wild -- and Aedes aegypti is not the only dengue carrier. Others worry that, since tiny percentages of the GM mosquitoes will actually be female and/or will survive, they will live on reproducing in the wild, posing unknown ecological threats. The researchers claim to have killed all the remaining mosquitoes with insecticide at the end of the trial in order to prevent this. But it seems unlikely -- dare I say impossible? -- that they could catch every stray mosquito weeks after releasing them, though a few lingering bugs compared to a few thousand might be inconsequential.

Even further skeptics are wary of Oxitec itself, claiming the company is losing millions each year but has a loan to pay back by 2013, and it's rushing into the mosquito trials as a result of panic. But as the company's chief scientific officer, Luke Alphey, tells ScienceInsider

"We are a for-profit company and finance is not irrelevant," he says. "But anyone who realizes that there are 50 to 100 million cases of dengue every year would feel a sense of urgency."

Skeptics or not, no one has much real data to judge with yet. The only other trial releasing GM mosquitoes into the wild so far took place last year in the Cayman Islands. Researchers there measured an 80 percent reduction in overall mosquito population where the modified animals were released. Here is a video about that trial:

Photo: David Wrobel/Getty Images

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Genetically Engineered Fruit Fly Smells Light

Fruit flies usually avoid light. But these larvae flock to it. That's because genetic scientists from Ruhr-Universitaet-Bochum Germany spliced a gene for a protein that activates under light into cells in the flies olfactory system that responds to smells. So when the light is turned on, the protein activates, but sends the signals through the fly larva's smell system. The fly perceives the odor of banana, marzipan or glue, normal smells present in rotting fruit, and go into the light.

The researchers are able to activate single receptor neurons out of 28 olfactory neurons in the larvae for this sensory perception. That gives them control over turning on cells that normally register repulsive odors and ones that register attractive odors.

The experiment doesn't hurt the flies but could give scientists more insight into how the smell sense works. Next, they try the experiment on adult flies and mice.

This experiment reminds me of a human condition called synesthesia, which causes people to hear colors or smell music. Perhaps this condition has a genetic source.

Gene Therapy Treats HIV

For many years, the human immunodefiency virus, or HIV, was misunderstood and practically untreatable. Now in 2009, the Centers for Disease Control reports that more than one million people are living with HIV in the United States. Most of these people deal with the symptoms of this disease through drug therapies. But now scientists are working on an alternative to drugs — gene therapy -- that could provide a lifetime protection against the disease. Listen to the Podcast.

Gene Therapy Treats HIV

Eric Dundon is a senior journalism student at the University of Missouri. There, he works in local media outlets with a particular interest in science, technology and sports reporting as well as print design.

Fear of Insurance Deters Genetic Tests

This week on the web site, we're talking about Genetic Science. One of the Top 10s looks at 10 genetic tests can help detect and diagnose everything from rare genetic disorders such as Huntington's disease to more common ailments like breast cancer and Down syndrome. Access to such tests could give people the information they need for possible treatments or to change their lifestyle in order to reduce their chances for a particular disease.

But a new study out of the University of Melbourne in Australia shows that 50 percent of participants declined genetic testing when informed of life insurance implications. The tests were for bowel cancer. One in every 3,000 Australians has a genetic mutation that puts them at high risk of bowel cancer. Researchers identified 106 people that had these genetic mutations and offered them a chance to learn more. Half declined, fearing that they might be declined by life insurance companies for benefits.