These cute little macaque monkeys may have gotten their fluffy brown fur from their father, their big eyes from their mother, and their good health from… their other mother.
The scientific advance heralded in a new paper in Nature is essentially procedural: Researchers have figured out how to make an embryo that does not carry the mitochondrial DNA of its mother but that of another female instead, which could prevent diseases that are caused by inherited defects in this genetic material. But the study’s immediate impact comes from the ethical questions it raises. “With this you have potentially three genetic parents,” said [bioethics expert] David Magnus…. “This will create the potential for legal and social conflicts.” [Washington Post].
While more than 99 percent of an embryo’s DNA comes from the union of a sperm cell with the nucleus inside a female egg, the other 1 percent is found in other structures outside the egg’s nucleus–the mitochondria, the cellular power plants that produce chemical energy. This mitochondrial DNA is inherited only from the mother, but in the new study on rhesus macaques researchers monkeyed with that biological truism.
When 18-year-old Caster Semenya blew past the competition in the women’s 800-meter race at the World Athletics Championships in Berlin this week, she got more than a gold medal. The South African athlete ran straight into a controversy about both the nature of gender and hers in particular. Some other runners contend that Semenya, with her stereotypically masculine build, is really a man, while the more temperate governing body, the International Association of Athletic Federations, says it needs to determine if she has male characteristics that give her an unfair advantage. To settle the question, the IAAF has ordered tests by a gynecologist, an endocrinologist, a gender expert, and a psychologist.
Gender expert Richard Auchus says assigning sex was hardly as easy as sizing someone up visually…. “For 99 percent of the population it’s easy to determine…. But one percent of the population have conditions that make it not so straightforward” [The New York Times]. In the 1960s, athletic federations began testing athletes by scraping cells from their mouths and testing them for a pair of X chromosomes, which typically establishes a person’s sex as female (as opposed to the XY chromosomes typically carried by males). But the tests were halted in the 1990s as critics pointed out that there are medical conditions that lead individuals with two X chromosomes to develop masculine characteristics, and others that mean individuals with one X and one Y chromosome never develop masculine characteristics. Some other individuals also exist outside the usual sexes of XX females and XY males; these may include males who are XXY, further confusing the tests [Nature News].
The discovery of a pair of genes that prompt rice plants to grow extra-tall when submerged in water could potentially lead to new hardier varieties of rice that yield food even in flooded conditions, and could help out farmers in flood-prone nations like Thailand and Cambodia, according to a study published in Nature.
Researchers discovered a pair of genes known as SNORKEL, which spurs growth among the plants when they are completely submerged, allowing the plants to survive by keeping their leaf tops above the water. As water levels rise, accumulation of the plant hormone ethylene activates the SNORKEL genes, making stem growth more rapid. When the researchers introduced the genes into rice that does not normally survive in deep water, they were able to rescue the plants from drowning [AP].
In an announcement certain to fuel conspiracy theories and science fiction stories alike, Israeli scientists revealed that they can fabricate blood and saliva samples that don’t contain DNA from the person who donated the samples, but rather hold the genetic code of an unrelated person. Theoretically, such samples could end up being used as false DNA evidence. Says lead researcher Dan Frumkin: “You can just engineer a crime scene…. Any biology undergraduate could perform this” [The New York Times]. While it might be easier for a shadowy crime scene-fixer to plant a stray hair or cigarette butt than to cook up a misleading batch of blood or saliva, researchers say that they can imagine scenarios in which blood or saliva would be more convincing.
Frumkin and his colleagues at the private company Nucleix used two different methods to create the false samples. In the first, the researchers take a tiny DNA sample from an individual’s hair or spit, and use a process called DNA amplification to increase the sample size. The researchers then took blood from another individual and put it through a centrifuge to remove the DNA-carrying white blood cells, leaving behind the red blood cells, which don’t carry DNA. They then added the applified DNA to the blood sample, et voila! When this engineered blood sample was sent to a leading forensic lab, the analysis detected the DNA of only the original individual, and saw nothing amiss.
But, don’t worry, like a hacker taking down servers to sell cyber security services, Nucleix has a fix: a system that can detect the difference between natural and manufactured DNA. It looks for a lack of methylation; an addition of methyl groups to DNA occurs naturally in genetic code, but it isn’t found in Nucleix’s manipulated DNA [Scientific American].
The next big leap in computing power may come from a surprising source: the genetic code. Researchers at IBM have found a way to use DNA strands as the scaffolding on which to place carbon nanotubes, creating tiny microchips that could eventually be more efficient and cheaper to produce than today’s silicon chips. To keep pace with Moore’s Law, which postulates that the number of transistors on an integrated circuit will double every two years, chip makers have to squeeze an increasing number of transistors onto every chip [Wired.com]. The new process offers an entirely different route to miniaturization.
Microchips are used in computers, cell phones and other electronic devices…. Right now, the tinier the chip, the more expensive the equipment. [An IBM spokesman] said that if the DNA origami process scales to production-level, manufacturers could trade hundreds of millions of dollars in complex tools for less than a million dollars of polymers, DNA solutions, and heating implements [Reuters].
Some lucky people don’t groan awake to the alarm clock when they’ve only gotten six hours of sleep–instead they pop out of bed, bright-eyed and invigorated and ready for a new day. Now, researchers investigating the phenomenon of people who don’t need as much sleep as the rest of us have found a rare genetic mutation that accounts for some cases of shortened sleep cycles.
The scientists were searching the samples for variations in several genes thought to be related to the sleep cycle. In what amounts to finding a needle in a haystack, they spotted two DNA samples with abnormal copies of a gene called DEC2, which is known to affect circadian rhythms [The New York Times]. When they looked up the volunteers who had given the two DNA samples, they found a mother and daughter who habitually get about six hours of sleep each night and report no ill effects.
Rising temperatures in Australia have caused birds on that continent to shrink–some by nearly 4 percent. The findings of a study published in the journal Proceedings of the Royal Society B are the first to show that birds’ sizes are affected by global warming, although this phenomenon previously has been shown in fish and Soay sheep. Scientists postulate that the relationship between a warmer climate and smaller animals may be true for the animal kingdom as a whole.
Temperature has a clear impact on body size; it’s old news among scientists that birds closer to the equator evolved to be smaller than their peers near the poles. One possible explanation for this, called Bergmann’s Rule, is that larger animals conserve heat more efficiently, and this trait is naturally selected for in colder climates, but not in warmer climates. On this basis, scientists have predicted that climate change will affect the way animals vary in size at different latitudes [ABC Science]. The recent research on sheep and fish has corroborated this hypothesis by showing that these animals have become smaller as temperatures have risen.
The genome of an HIV virus is a truly twisted thing, but now for the first time researchers have traced its every fold and contour. By mapping its entire structure, they hope to gain a greater understanding of how the virus operates, and potentially accelerate the development of drug treatments [BBC News]. Usually geneticists focus on the sequence of genes that comprise an organism’s genome, but recent evidence suggests that the structure can also play a role in how it functions.
Like many other viruses, the HIV genome consists of single-strand RNA, rather than the double-stranded DNA found in most animals. Though scientists have identified HIV’s genes and their order, just one-fifth of its genome has been described in precise spatial detail. That’s important because genomes don’t look anything like the neatly linear, bar code-like pictures returned by basic sequencing techniques. In reality, genomes are arranged in intricate, three-dimensional loops and whorls. And just as a list of machines isn’t very useful without a description of their arrangement on a factory floor, structure matters [Wired.com].
Scientists have created genetically engineered corn plants that resist a root-destroying larvae by emitting a chemical call for help, summoning a parasite that preys on the larvae.
The larvae of the western corn rootworm (actually a beetle) is considered the most destructive corn pest in the United States and plagues parts of Europe as well. Known as the billion-dollar bug, the rootworm is said to be responsible for crop damage and pest-control spending valued at more than nine figures [National Geographic News]. To fight the larvae without the use of synthetic pesticides, researchers created corn plants that release a chemical compound into the soil, which calls forth parasitic nematodes to come and infest the beetle larvae.
Scientists trying to determine where dogs were first domesticated have been sent back to the drawing board by a new study. Back in 2002, researchers sampled DNA from dogs around the world, and determined that dogs in East Asia had the most genetic diversity, suggesting that the species originated there and that dogs in that region have had the longest time to evolve. But the new study suggests that those earlier results were skewed, because DNA sampling of African street dogs has revealed equal genetic diversity.
The earlier findings may have been thrown off because the large-scale study included both purebred dogs, whose evolution has been closely guided by human hands, and street dogs, who have bred more autonomously and randomly, and who therefore show more genetic diversity. But the 2002 researchers drew DNA from different types of dogs in different regions. Says Adam Boyko, lead researcher of the new study: “I think it means that the conclusion that was drawn before might have been premature. It’s a consequence of having a lot of street dogs from East Asia that were sampled, compared to elsewhere” [BBC News].
Changes in an organism’s genome that once took years to make in a lab can now be done in a fraction of the time, thanks to a new method of genome engineering. “This technique allows us to do some amount of rapid evolution” [New Scientist], says lead researcher Harris Wang.
In the experiment, the scientists used a technique called Multiplex Automated Genome Engineering, or MAGE, to program E. coli bacteria to produce five times as much of an antioxidant called lycopene than normal. In addition, using the process, which grafts pieces of synthetic DNA into the genomes of dividing cells, researchers generated 15 billion different genomic patterns in just three days. The process would normally take years, and could eventually be used to produce industrial chemicals, drugs, fuel and anything else that comes out of bacteria [Wired.com]. The process is significantly faster than previous techniques, in which scientists had to modify genes by changing bases one by one, for example, or by cutting genes from one genome and gluing them into another, modifying and inserting them one at a time.
From reprogrammed skin cells, scientists have made live mice.
The accomplishment is the latest step forward in the exciting new field of reprogrammed cells, which may offer an alternative to embryonic stem cells…. [It's] the most definitive evidence yet that the technique could help sidestep many of the explosive ethical issues engulfing the controversial field [Washington Post]. Two new studies describe the process, and one team of researchers reports producing 27 live mice. While there were abnormalities and unusual deaths with some of the first generation of mice, [the] team produced enough normal mice this way to create hundreds of second and third generation mice [AP].
It was only three years ago that Japanese stem cell researchers found a way to reprogram ordinary skin cells to behave like embryonic stem cells, which are thought to hold vast potential for medical research because they can develop into any kind of body tissue–from heart cells to toenail cells. But researchers didn’t know if the reprogrammed adult cells, known as induced pluripotent stem cells or iPS cells, were capable of differentiating into every type of tissue, the way embryonic stem cells do.
Young baseball players in Latin America with big dreams of coming to the United States to play in the big leagues have to do more than work on their batting and fielding these days–they may also have to prove that they are who they say they are. Baseball has been beset by a series of assumed identity scandals; for example, the young baseball phenom, Esmailyn Gonzalez, received a $1.4-million bonus when he signed with the Washington Nationals in 2006. This February, the player who was misrepresenting himself as only 19 years old turned out to be a 23-year-old by the name of Carlos David Alvarez Lugo [Scientific American].
To combat the problem, Major League Baseball investigators have begun giving DNA tests to some prospects to determine whether they are actually related to the people they identify as their parents, and aren’t just borrowing them along with the birth certificate of a younger man. A statement from Major League Baseball said that it used DNA testing in the Dominican Republic “in very rare instances and only on a consensual basis to deal with the identity fraud problem that the league faces in that country.” The statement added that the results of the tests were not used for any other purpose [The New York Times]. But the testing raises ethical questions, and could even be declared illegal when a new law takes effect later this year.
Why does a wiener dog look like a wiener, with its body poised on such short, stubby legs? Researchers say they’ve discovered the answer in a single genetic mutation that’s found in dachshunds, corgis, basset hounds, and other short-legged dog breeds. Study coauthor Heidi Parker says this gene may turn on growth mechanisms at the wrong time during foetal development, stunting the growth of long bones in the leg and making them curvy. The trait affects only the legs, unlike the small-all-over effect seen in miniature or toy breeds, such as poodles [Reuters].
The mutation popped up sometime after modern dogs diverged from wolves, researchers say, and it’s a dominant gene–meaning that a dog with only one copy of the gene will show obvious signs of it. Having joined the genetic repertoire of dogs, the gene was available for selection by dog breeders whenever they wanted to develop a downsized breed. The basset hound, for example, was bred for its short legs so people on horseback could keep up with it during hunting, Dr. Parker said [The New York Times].
Earlier this week, the oil giant ExxonMobil announced a significant shift in direction: Rather than drilling ever downward in an attempt to find more oil, the company will invest heavily in green, growing things that can manufacture biofuel. Exxon plans to put $600 million into the production of algae-based biofuels, and will partner with the genetics company Synthetic Genomics run by genomics pioneer Craig Venter. The announcement came just a week after another industrial giant, Dow Chemical, declared its own investment in algae technology.
The biofuel industry is currently facing a shift from first-generation biofuels to so-called advanced biofuels as evidence mounts that corn-based ethanol and soybean biodiesel are not as ecologically, socially or economically sustainable as many first thought…. Algae have been touted as a better organic material for producing biofuel by many researchers and entrepreneurs. It does not take up any arable land and can be grown in controlled conditions; at a basic level algae only needs water, sunlight, carbon dioxide and some nutrients to grow [CNN].
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These cute little macaque monkeys may have gotten their fluffy brown fur from their father, their big eyes from their mother, and their good health from… their other mother.
When 18-year-old Caster Semenya blew past the competition in the women’s 800-meter 
In an announcement certain to fuel conspiracy theories and science fiction stories alike, Israeli scientists revealed that they can fabricate blood and saliva samples that don’t contain 
The next big leap in 
Some lucky people don’t groan awake to the alarm clock when they’ve only gotten six hours of 
Rising temperatures in Australia have caused 
The genome of an 
Scientists have created 
Scientists trying to determine where 
Changes in an organism’s genome that once took years to make in a lab can now be done in a fraction of the time, thanks to a new method of 
From reprogrammed skin cells, scientists have made live mice.
Young 
Why does a wiener 
Earlier this week, the oil giant ExxonMobil announced a significant shift in direction: Rather than drilling ever downward in an attempt to find more 
