Prevailing wisdom holds that every cell in the body contains identical DNA.
“We found that humans are made up of a mosaic of cells with different genomes,” said lead author Flora Vaccarino, M.D., from the Yale Child Study Center. “We saw that 30 percent of skin cells harbor copy number variations (CNV), which are segments of DNA that are deleted or duplicated. Previously it was assumed that these variations only occurred in cases of disease, such as cancer. The mosaic that we’ve seen in the skin could also be found in the blood, in the brain, and in other parts of the human body.”
It’s been long believed that all of our cells have the very same DNA sequence.
Other scientists conducting similar genetic research have theorized the DNA sequence of a cell could be modified during the cell’s development – when DNA is copied from a mother cell to a daughter cell. These many changes to a cell’s original DNA, they say, could affect an entire group of genes.
While it’s difficult for scientists to actually test these theories, the Yale researchers say they have been able to do so for their new study.
To reach their findings, the research team used whole genome sequencing – a genome is a complete set of hereditary information – to study induced pluripotent stem cells (iPS), which are genetically engineered stem cells developed from a mature-differentiated cell.
The team grew cells taken from the inner upper arms of people from two families. For two years, the researchers examined their genetically engineered iPS cell lines, compared them to the original skin cells, and noted any differences between each cell’s DNA.
The team also conducted further experiments to see what might have caused the differences to occur.
While the research in the project outlined in this recent study was limited to finding variations in DNA sequencing within skin cells, the Yale team is continuing its studies to see if these same DNA variations can be found in developing brain cells of animals as well as humans.
Scientists have discovered what could be the oldest, most distant galaxy in the universe, thanks to a unique combination of man-made and natural telescopes.
The newly discovered galaxy, MACS0647-JD, was found by the Cluster Lensing And Supernova Survey with Hubble (CLASH).
It is about 13.3 billion light years, or 125,825,000,000,000,000,000,000 km, from Earth. Scientists are getting to see it just as it was 420 million years after the Big Bang, or when the universe was only three percent of its current age of about 13.7 billion years.
Astronomers made the discovery by combining the power of the Hubble Space Telescope, the Spitzer Space Telescope and a natural zoom effect called gravitational lensing, which uses enormous galaxy clusters as interstellar telescopes to magnify distant galaxies behind them.
The effect is achieved when the light rays from the distant object are bent by the gravity of the huge galaxy clusters, just like a giant cosmic lens, that lie between the object and Earth.
“While one occasionally expects to find an extremely distant galaxy using the tremendous power of gravitational lensing, this latest discovery has outstripped even my expectations of what would be possible with the CLASH program,” said Rychard Bouwens of Leiden University in the Netherlands, a co-author of the study that outlined the discovery. “The science output in this regard has been incredible.”
The massive galaxy cluster that’s making the distant galaxy appear brighter than it normally would, providing the natural boost to the Hubble and Spitzer telescopes, , is called MACS J0647.7+7015 and is about five billion light years away.
Because of the gravitational lensing provided by the cluster, the CLASH team was able to observe three magnified images of MACS0647-JD with the Hubble.
“This cluster does what no man-made telescope can do,” said Marc Postman of the Space Telescope Science Institute, who leads the CLASH team. “Without the magnification, it would require a Herculean effort to observe this galaxy.”
The astronomers say that the distant galaxy is so small, about 600 light years across according to their observations that it may be going through its first stages formation. Our own Milky Way galaxy is about 150,000 light years across.
“This object may be one of many building blocks of a galaxy,” says Dan Coe from the Space Telescope Institute and lead author of the study. “Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments.”
The galaxy could turn out to be too far away for astronomers to confirm its distance with any of the current available technology. But once the new James Webb Space Telescope launches in 2018, astronomers expect to be able to take a definitive measurement of its distance and to study the properties of the galaxy in more detail.
MACS0647-JD, is very young and only a tiny fraction of the size of our Milky Way. The object is observed 420 million years after the big bang. (Video: NASA, ESA, and G. Bacon (STScI))
An international team of astronomers using the European Southern Observatory’s Very Large Telescope (VLT) and the Canada-France-Hawaii Telescope has identified what they’re calling the most exciting free-floating, or rogue planet ever found.
Writing in the journal Astronomy & Astrophysics, the scientists say this rogue planet, located relatively close to our own Solar System – about only 100 light years from Earth — may help explain how planets and stars form.
A free-floating planet is one that has no gravitational ties to any particular star or other stellar object so it wanders alone in space. Also called orphan or nomad planets, these objects are believed to have been ejected from their original home solar system at some time in the distant past.
While objects such as this have been found before, scientists haven’t been too clear on whether or not they were true planets or if they were, perhaps, brown dwarfs, which are stars that failed to fully form and are unable to generate or sustain the needed nuclear fusion to become true stars.
Since this newly identified rogue planet doesn’t have a very bright star close to it, the astronomers say that they were able to study it and its atmosphere in great detail.
“Looking for planets around their stars is akin to studying a firefly sitting one centimeter away from a distant, powerful car headlight,” says Philippe Delorme from the Institut de planétologie et d’astrophysique de Grenoble, lead author of the study that identified the new planetary object. “This nearby free-floating object offered the opportunity to study the firefly in detail without the dazzling lights of the car messing everything up.”
Astronomers say that this newly discovered object, called CFBDSIR2149, seems to be traveling along with a group of young stars that may have all formed at the same time called the AB Doradus Moving Group. This group of about 30 or so stars is also moving through space with the star AB Doradus, the primary star within a three star system found in the constellation Dorado.
The scientists say that this planetary object is the first that was ever identified within a moving group of stars. And, if they find that it’s actually linked with the AB Doradus Moving Group, it, like the stars in the group, would be a relatively young object.
A real association between this nomad planet with the moving star group, according to the astronomers, could make it easier for them to figure out the object’s age, temperature, mass and atmospheric composition.
But the scientists say there’s also a small chance that the planet’s relationship with the moving star group might be by chance.
If it’s found that the planetary object isn’t actually associated with the group, the astronomers say that it would be trickier to track down its nature and physical properties.
“Further work should confirm CFBDSIR2149 as a free-floating planet,” says Delorme. “This object could be used as a benchmark for understanding the physics of any similar exoplanets that are discovered by future special high-contrast imaging systems, including the SPHERE instrument that will be installed on the VLT.”
The toxic seaweed begins its lethal damage upon contact with the coral, killing its tissue within two to three days of contact.
But now scientists at the Georgia Institute of Technology have found that one species of coral near the Fiji Islands doesn’t sit around waiting to destroyed; it actually sends out a call for help when it’s threatened by poisonous seaweed.
Small fish, known as gobies, which are about two centimeters long and spend their entire lives in the crevices of the coral, respond to the coral’s alarm within minutes.
The gobies go after the seaweed, chewing and mowing it away from the coral. Not only do the little fish protect their homes, but some species also use the toxic substances from the seaweed to build up their own protective arsenal.
Hay said two species of goby serve as coral bodyguards. One species simply chews away at the harmful seaweed and then spits it out, but the other type of fish actually ingests the poisonous substance. This enhances the fish’s already toxic characteristics, increasing its ability to protect itself from predators.
Researchers were unable to determine whether the fish were saving up the lethal seaweed compounds to use on enemies, or if they were already making their own poisons, and using the noxious material to build up their resistance to the poisons.
Not all fish possess the gobies’ protective instincts. Scientists also studied two other species of small fish that live in the coral.
According to Hay, these damsel fish simply swim away, moving on to other coral, when their homes are threatened.
“They just abandon it, say ‘It’s going to die, we’re out of here,’” Hay says.
Interestingly enough, the gobies are only protective when their particular species of coral is under attack. The scientists placed the gobies within another closely-related species of coral and found that the little bodyguards did not respond or protect their new home when it was under a similar threat.
Hay hopes to study other species of coral in the future to see if they too are also aided by rapid responding protective fish.
Mark Hay joins us this weekend on the radio edition of Science World. Tune in (see right column for scheduled times) or check out the interview below.
Looking old on the outside might be a clue to what’s going on inside your body, according to new research from the American Heart Association.
The study finds that people who have three or four physical signs of aging —a receding hairline, baldness, a crease in the earlobe, or yellow fatty deposits around the eyelid— also have a 57 percent increased risk for heart attack and a 39 percent increased risk for heart disease.
“The visible signs of aging reflect physiologic or biological age, not chronological age, and are independent of chronological age,” said Anne Tybjærg-Hansen, M.D., the study’s senior author and professor of clinical biochemistry at the University of Copenhagen in Denmark.
Tybjærg-Hansen and her colleagues studied nearly 11,000 test participants as part of the Copenhagen City Heart Study. They were 40 or older, and almost half were women.
In the study group, 7,537 of them had frontoparietal baldness, which is a receding hairline at the temples; 3,938 were bald at the top of their heads; 3,405 had an earlobe crease; and 678 had yellow fatty deposits around the eye.
Over a 35-year period, researchers followed the subjects and found that 3,401 of them developed heart disease and 1,708 experienced a heart attack.
Looking at the test subjects both individually and as a group, researchers found that the identified signs of aging were predictors of heart attack and heart disease, or both, without considering traditional risk factors, such as high-blood pressure, cholesterol, smoking, physical inactivity or obesity.
In particular, the study found that fatty deposits around the eye were the strongest single predictor of both heart attack and heart disease.
Each additional sign of aging, among both men and women, suggested an increased risk of heart attack and heart disease. So if an individual initially had a receding hairline but later developed an ear crease, the risk of heart problems increased as well.
The study found that those in their seventies, and those who had those multiple aging signs, had the highest risk of coronary problems.
To gather data for the study, various healthcare workers, including nurses and laboratory technicians, examined the test subjects, recording the amount of gray hair they had; how wrinkled their faces were; the type and level of baldness; and whether or not they had an earlobe crease or eyelid deposits.
These findings, according to the researchers, suggest that doctors and other healthcare workers should look for these external signs of heart problems, while also considering traditional risks.
“Checking these visible aging signs should be a routine part of every doctor’s physical examination,” Tybjærg-Hansen said.
The US space agency is offering a new service which alerts people a few hours before the space station is visible flying overhead.
Enthusiasts who sign up the new service, Spot the Station, will receive notifications via email or text message. The program coincides with the Nov. 2 12-year anniversary of ISS crews living and working continuously aboard the orbiting space station.
“It’s really remarkable to see the space station fly overhead and to realize humans built an orbital complex that can be spotted from Earth by almost anyone looking up at just the right moment,” says NASA’s William Gerstenmaier. “We’re accomplishing science on the space station that is helping to improve life on Earth and paving the way for future exploration of deep space.”
The ISS, which flies about 322 km above us, is usually best glimpsed either at dawn or dusk. Next to the moon, it is the brightest object in the night sky. On a clear night, NASA says the space station can be seen as a point of light traveling at about the speed of a fast-moving airplane.
The space station’s size and brightness are about the same as the planet Venus.
Most of the world’s population should be able to see the ISS since it passes over more than 90 percent of people living on Earth.
People who sign up for ”Spot the Station” will be able set their alerts for morning or evening sightings, or both. Also, the new service won’t waste your time or eat up text message units by sending useless information. NASA says it will send notification messages for good sightings only, which is when the ISS passes high enough in the sky to be easily seen over objects like trees and buildings.
NASA’s Johnson Space Center in Houston, Texas, calculates and updates ISS sighting information twice a week for more 4,600 cities and towns throughout the world. The space agency suggests people choose the location nearest to them if they can’t find their specific position on the list.
President Ronald Reagan, during his 1984 State of the Union address, committed the United States to developing a permanently-occupied space station that would not only involve NASA. Other countries were invited to participate as well.
After years of planning and negotiation, the ISS has become a truly international venture. Sixteen nations participate in what NASA calls the most technically and politically complex space exploration program ever undertaken.
The unique partnership includes the space agencies of the United States, Russia, Europe, Japan and Canada, as well as nations that are a part of the European Space Agency: France, Germany, Italy, Denmark, Sweden, Belgium, Netherlands, Spain, United Kingdom, Switzerland, and Norway.
The first portion of what would become the massive International Space Station was launched from the Baikonur Cosmodrome, Kazakstan, on Nov. 20, 1998. Called the Zarya, or “Sunrise,” this ISS module was designed to provide the station’s initial propulsion and power. The space station has a mass of about 450,000 kg, is 72.8 m in length, by 108.5 m in width and is about 20 m in height.
The first humans, a three-person crew known as Expedition 1, boarded the space station on Nov. 2, 2000. The ISS has been continuously staffed with international crews since, hosting 207 people who lived on the space station from a period of weeks to months.
Currently, the lone way crews can be transported to and from the ISS is aboard Russian Soyuz spacecraft. The US is turning to the private sector to help with crew transport after retiring the space shuttle fleet in 2011. NASA
NASA time-lapse animation of the assembly of the International Space Station
Yale researchers found genetic evidence that helpful bacteria, which normally live the bellies of honeybees, have become highly resistant to the antibiotic tetracycline, possibly weakening the bees’ ability to fight disease.
Researchers say decades of use may have unknowingly encouraged antibiotic resistance by genetically altering the beneficial bacteria.
Past studies show helpful bacterial play an important role in protecting the honeybee by neutralizing toxins found in their diets while also helping fight off various pathogens.
The researchers have identified eight different tetracycline resistance genes among U.S. honeybees that were exposed to antibiotics. Those same resistance genes were missing in bees from countries where antibiotic use is banned.
“It seems to be everywhere in the U.S.,” says Nancy Moran of Yale University, a senior author on the study. “There’s a pattern here, where the U.S. has these genes and the others don’t.”
In the 1950s, beekeepers started using the antibiotic oxytetracycline, a compound similar to tetracycline, which is commonly used in humans. They were trying to fight a devastating bacterial disease called foulbrood, which can wipe out a hive more quickly than beekeepers can react to the infection.
But after years of use the microorganisms eventually acquired a resistance to tetracycline, possibly weakening the honeybee’s resistance to other diseases.
“It seems likely this reflects a history of using oxytetracycline since the 1950s,” says Moran. “It’s not terribly surprising. It parallels findings in other domestic animals, like chickens and pigs.”
The researchers took bee samples from the Czech Republic, New Zealand and Switzerland, which do not allow their beekeepers to use the antibiotics.
Researchers found those bees had only two or three different resistance genes and even then only in very low numbers, suggesting that prolonged antibiotic use in the US bees may have played a role in developing the resistance genes.
Moran points out that the antibiotic-resistant genes researchers found in the bellies of the honeybee do not pose a direct risk to humans.
Those microorganisms, according to Moran, “don’t actually live in the honey, they live in the bee. We’ve never actually detected them in the honey. When people are eating honey, they’re not eating these bacteria.”
Nancy Moran joins us this weekend on the radio edition of Science World. She tells us more about how treatment meant to strengthen honeybee hives in the U.S. may have actually weakened them instead. Tune in (see right column for scheduled times) or check out the interview below.
The Earth and its moon started with a big bang, according to a new theory from NASA scientists, who believe both were born out of collisions between two massive developing planets.The new theory suggests the two giant planetary bodies, each about five times the size of Mars, collided with each other twice.
After the first collision, the planets smashed into each other again, leaving behind material which resulted in our early Earth. The fledgling planet was surrounded by a disk of left-over material, which later combined to form the moon.
This new theory challenges the widely-held “giant impact hypothesis,” which suggests the moon formed early in our solar system’s history after an enormous impact between Earth and a Mars-sized planet that was still being formed. Some call that protoplanet Theia, after the mother of the goddess of the moon in Greek mythology.
However, skeptics say if the Theia theory were true, Earth and the moon would have different chemical compositions from each other, which they don’t.
According to the new NASA theory, the two collisions, along with the subsequent melding of left-over material, formed both the Earth and the moon, which is why they have similar chemical compositions. “Our understanding of the solar system is constantly being refined with each new discovery,” says NASA’s Greg Schmidt. “This research illustrates the importance of modeling planetary formation to enhance our scientific understanding of the moon and its place in the solar system.”
Canup says her work was inspired by previous studies on the early history of the moon, which explain the similar chemical composition of the Earth and moon, while at the same time producing an appropriate mass for Earth and the moon.
“The ultimate likelihood of each impact scenario will need to be assessed by improved models of terrestrial planet formation,” Canup said. Canup’s work is outlined in Science.
Video: A computer simulation of a low-velocity collision of two protoplanets that contain 45 and 55 percent of the Earth’s mass. Colors indicate particle temperature in kelvin, with blue-to-red indicating temperatures from 2,000 K to in excess of 6,440 K. After the first protoplanetary impact, they re-collide, merge and form a rapidly spinning Earth-mass planet that is surrounded by a disk of particles that would later form the Moon. (Video: Southwest Research Institute)