Posts Tagged ‘DNA’

The animation on the left comes from a series of images taken by Eadweard Muybridge of the mare, Annie G, galloping. The frames were encoded in genetic material and stored in living bacteria. The animation on the right shows the frames after multiple generations of bacterial growth, recovered by sequencing the bacterial genomes.
Photograph: Seth Shipman

His groundbreaking photos showed life in motion, from cantering bison to leapfrogging boys, and settled an argument that had long divided trainers and riders: do all four hooves of a racehorse ever leave the floor at once?

Now, more than a century later, the stills and animations of Eadweard Muybridge, the eccentric Englishman and father of the motion picture, have had a modern makeover. Where Muybridge captured his pictures on photographic plates, Harvard scientists have set them in DNA.

There is more to the feat than showing off. If cells can be made to store information, the applications are vast. Microbes could be turned into living sentinels to monitor environmental pollution. Meanwhile, neurons could be programmed to record how the brain develops in a living animal.

“We encoded images and a movie into DNA in a living cell which is fun, but it’s not really the point of the system,” said Seth Shipman, a geneticist at Harvard Medical School. “What we’re trying to develop is a molecular recorder that can sit inside living cells and collect data over time.”

To build the prototype molecular recorder, the Harvard team hacked the immune defences that protect bacteria from invading viruses. When a bacterium is breached by an intruding virus, it releases enzymes to chop up the virus’s genetic code. To make sure it is prepared for future attacks, the bacterium remembers the invader by adding a chunk of the virus’s genetic code to its own genome. Over time, the bacterium’s genome expands, like bits of food stuck on a kebab skewer, to incorporate more and more chunks of DNA from viral intruders.

Shipman and his colleagues created strands of synthetic DNA in the lab that encoded in the letters G, T, C and A, the positions and shades of pixels found in an image of a hand and five pictures of a galloping horse taken by Muybridge in the 1880s. The scientists then fed the strands of DNA to E. coli bacteria. The bugs treated the strips of DNA like invading viruses and dutifully added them to their own genomes.

The researchers left the bugs in a dish for a week during which time they grew and divided into new bacterial cells. Shipman then collected some of the bacteria and read out their genomes. He found that the synthetic strands of DNA, which carried all the information needed to reconstruct either the hand image or the pictures of the galloping horse, had been spliced into the bugs’ genetic code.

“We delivered the material that encoded the horse images one frame at a time,” Shipman said. “Then, when we sequence the bacteria, we looked at where the frames were in the genome. That told us the order in which the frames should then appear.” Even though the bugs had grown and divided over the week, they had retained the synthetic strands of DNA which Shipman used to reconstruct the images with 90% accuracy.

“What this shows us is that we can get the information in, we can get the information out, and we can understand how the timing works too,” he said. Details of the work are reported in Nature.

Muybridge pioneered motion pictures with help from a contraption called the zoopraxiscope which projected sequences of images held on spinning glass discs. He dedicated much of his life to unveiling the beauty of animals in motion, even through the disruption of 1874 when he tracked down his younger wife’s lover, shot him point black, and was acquitted on the grounds of justifiable homicide, despite the jury having dismissed his plea of insanity brought on by a head injury suffered in a stagecoach crash in Texas 14 years earlier.

Eadweard by name and weird by nature, Muybridge was born Edward Muggeridge in Kingston upon Thames in 1830, but adopted what he believed to be the original AngloSaxon form of his name. His work on horses, including the images of the mare, Annie G, which Shipman stored in bacteria, was commissioned by Leland Stanford, a businessman, racehorse-owner and former governor of California, to settle a longstanding debate over whether a racehorse ever lifted all four hooves off the ground at once. In other work, Muybridge captured the precise motion of a nude woman turning around in surprise and another hopping on the spot.

While bacteria might not be great for storing data for thousands of years, the bugs could work well when information only has to be kept for days, weeks or months, Shipman said. Because bacteria thrive happily in the environment, the bugs could be spread on soil where they could keep a running record of heavy metals and other pollutants.

But that is only one potential use. Living cells could also be made to record what happens inside them or in the tissues and fluids that surround them. A neuroscientist by training, Shipman said that scientists have long struggled to understand brain development because it is hard to make measurements without interfering with the process. “If we had cells that recorded information inside the brain, the whole organ could develop and you could go in and retrieve the data once it’s all done,” he said.

https://www.theguardian.com/science/2017/jul/12/scientists-pioneer-a-new-revolution-in-biology-by-embeding-film-on-dna#img-3

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by Jason Daley

Fiinding bones from early humans and their ancestors is difficult and rare—often requiring scientists to sort through the sediment floor of caves in far-flung locations. But modern advances in technology could completely transform the field. As Gina Kolta reports for The New York Times, a new study documents a method to extract and sequence fragments of hominid DNA from samples of cave dirt.

The study, published this week in the journal Science, could completely change the type of evidence available to study our ancestral past. Researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, collected 85 sediment samples from seven archeological sites in Belgium, Croatia, France, Russia and Spain, covering a span of time from 550,000 to 14,000 years ago.

As Lizzie Wade at Science reports, when the team first sequenced the DNA from the sediments, they were overwhelmed. There are trillions of fragments of DNA in a teaspoon of dirt, mostly material from other mammals, including woolly mammoth, woolly rhinoceroses, cave bears and cave hyenas. To cut through the clutter and examine only hominid DNA, they created a molecular “hook” made from the mitochondrial DNA of modern humans. The hook was able to capture DNA fragments that most resembled itself, pulling out fragments from Neanderthals at four sites, including in sediment layers where bones or tools from the species were not present. They also found more DNA from Denisovans, an enigmatic human ancestor found only in single cave in Russia.

“It’s a great breakthrough,” Chris Stringer, anthropologist at the Natural History Museum in London tells Wade. “Anyone who’s digging cave sites from the Pleistocene now should put [screening sediments for human DNA] on their list of things that they must do.”

So how did the DNA get there? The researchers can’t say exactly, but it wouldn’t be too difficult. Humans shed DNA constantly. Any traces of urine, feces, spit, sweat, blood or hair would all contain minute bits of DNA. These compounds actually bind with minerals in bone, and likely did the same with minerals in the soil, preserving it, reports Charles Q. Choi at LiveScience.

There’s another—slightly scarier—option for the DNA’s origins. The researchers found a lot of hyena DNA at the study sites, Matthias Meyer, an author of the study tells Choi. “Maybe the hyenas were eating human corpses outside the caves, and went into the caves and left feces there, and maybe entrapped in the hyena feces was human DNA.”

The idea of pulling ancient DNA out of sediments is not new. As Kolta reports, researchers have previously successfully recovered DNA fragments of prehistoric mammals from a cave in Colorado. But having a technique aimed at finding DNA from humans and human ancestors could revolutionize the field. Wade points out that such a technique might have helped produce evidence for the claim earlier this week that hominids were in North America 130,000 years ago.

DNA analysis of sediments might eventually become a routine part of archeology, similar to radio carbon dating, says Svante Pääbo, director of the Evolutionary Genetics department at the Max Planck Institute for Evolutionary Anthropology, in the press release. The technique could also allow researchers to start searching for traces of early hominids at sites outside of caves.

“If it worked, it would provide a much richer picture of the geographic distribution and migration patterns of ancient humans, one that was not limited by the small number of bones that have been found,” David Reich, Harvard geneticist tells Kolta. “That would be a magical thing to do.”

As Wade reports, the technique could also solve many mysteries, including determining whether certain tools and sites were created by humans or Neanderthals. It could also reveal even more hominid species that we have not found bones for, creating an even more complete human family tree.

Read more: http://www.smithsonianmag.com/smart-news/new-technique-pulls-ancient-human-dna-out-cave-soil-180963084/#5gzaxagh8RYmlP6s.99

A 13,000-year-old bison fossil has shown the most likely migration route of some of the first native Americans.

DNA from the bison remains has narrowed down when an ice-free corridor opened up along the Rocky Mountains during the late Pleistocene.

That corridor was a vital route for migrations between what is now Alaska and Yukon in the far north and the rest of the North American continent.

Researchers had previously suspected this was the way migrating humans and animals must have travelled, but were unclear about how and when it was used.

But now, a new study published in Proceedings of the National Academy of Sciences, shows the route was fully open by about 13,000 years ago.

While this route was closed when the very first humans moved south of the ice sheets into North America around 15,000 years ago (they probably took a Pacific coastal route), it is thought it later became a well-travelled thoroughfare in both directions.

“The opening of the corridor provided new opportunities for migration and the exchange of ideas between people living north and south of the ice sheets,” said Peter Heintzman, of UC Santa Cruz, who led the DNA analysis.

His coauthor Beth Shapiro, also from UC Santa Cruz, has previously shown that bison populations north and south of the ice sheets were genetically distinct by the time the corridor opened.

So, armed with that knowledge, the researchers have been able track the movement of northern bison southward, and southern bison northward.

“The radiocarbon dates told us how old the fossils were, but the key thing was the genetic analysis, because that told us when bison from the northern and southern populations were able to meet within the corridor,” Heintzman said.

https://cosmosmagazine.com/life-sciences/ice-age-bison-dna-sheds-light-human-migration

The elusive octopus genome has finally been untangled, which should allow scientists to discover answers to long-mysterious questions about the animal’s alienlike physiology: How does it camouflage itself so expertly? How does it control—and regenerate—those eight flexible arms and thousands of suckers? And, most vexing: How did a relative of the snail get to be so incredibly smart—able to learn quickly, solve puzzles and even use tools?

The findings, in Nature, reveal a vast, unexplored landscape full of novel genes, unlikely rearrangements—and some evolutionary solutions that look remarkably similar to those found in humans.

With the largest-known genome in the invertebrate world—similar in size to that of a house cat (2.7 billion base pairs) and with more genes (33,000) than humans (20,000 to 25,000)—the octopus sequence has long been known to be large and confusing. Even without a genetic map, these animals and their cephalopod cousins (squids, cuttlefishes and nautiluses) have been common subjects for neurobiology and pharmacology research. But a sequence for this group of mollusks has been “sorely needed,” says Annie Lindgren, a cephalopod researcher at Portland State University who was not involved in the new research. “Think about trying to assemble a puzzle, picture side down,” she says of octopus research to date. “A genome gives us a picture to work with.”

Among the biggest surprises contained within the genome—eliciting exclamation point–ridden e-mails from cephalopod researchers—is that octopuses possess a large group of familiar genes that are involved in developing a complex neural network and have been found to be enriched in other animals, such as mammals, with substantial processing power. Known as protocadherin genes, they “were previously thought to be expanded only in vertebrates,” says Clifton Ragsdale, an associate professor of neurobiology at the University of Chicago and a co-author of the new paper. Such genes join the list of independently evolved features we share with octopuses—including camera-type eyes (with a lens, iris and retina), closed circulatory systems and large brains.

Having followed such a vastly different evolutionary path to intelligence, however, the octopus nervous system is an especially rich subject for study. “For neurobiologists, it’s intriguing to understand how a completely distinct group has developed big, complex brains,” says Joshua Rosenthal of the University of Puerto Rico’s Institute of Neurobiology. “Now with this paper, we can better understand the molecular underpinnings.”

Part of octopuses’ sophisticated wiring system—which extends beyond the brain and is largely distributed throughout the body—controls their blink-of-an-eye camouflage. Researchers have been unsure how octopuses orchestrate their chromatophores, the pigment-filled sacs that expand and contract in milliseconds to alter their overall color and patterning. But with the sequenced genome in hand, scientists can now learn more about how this flashy system works—an enticing insight for neuroscientists and engineers alike.

Also contained in the octopus genome (represented by the California two-spot octopus, Octopus bimaculoides) are numerous previously unknown genes—including novel ones that help the octopus “taste” with its suckers. Researchers can also now peer deeper into the past of this rarely fossilized animal’s evolutionary history—even beyond their divergence with squid some 270 million years ago. In all of that time octopuses have become adept at tweaking their own genetic codes (known as RNA editing, which occurs in humans and other animals but at an extreme rate in octopuses), helping them keep nerves firing on cue at extreme temperatures. The new genetic analysis also found genes that can move around on the genome (known as transposons), which might play a role in boosting learning and memory.

One thing not found in the octopus genome, however, is evidence that its code had undergone wholesale duplication (as the genome of vertebrates had, which allowed the extra genes to acquire new functions). This was a surprise to researchers who had long marveled at the octopus’s complexity—and repeatedly stumbled over large amounts of repeated genetic code in earlier research.

The size of the octopus genome, combined with the large number of repeating sequences and, as Ragsdale describes, a “bizarre lack of interest from many genomicists,” made the task a challenging one. He was among the dozens of researchers who banded together in early 2012 to form the Cephalopod Sequencing Consortium, “to address the pressing need for genome sequencing of cephalopod mollusks,” as they noted in a white paper published later that year in Standards in Genomic Sciences.

The full octopus genome promises to make a splash in fields stretching from neurobiology to evolution to engineering. “This is such an exciting paper and a really significant step forward,” says Lindgren, who studies relationships among octopuses, which have evolved to inhabit all of the world’s oceans—from warm tidal shallows to the freezing Antarctic depths. For her and other cephalopod scientists, “having a whole genome is like suddenly getting a key to the biggest library in the world that previously you could only look into by peeking through partially blocked windows.”

http://www.scientificamerican.com/article/octopus-genome-reveals-secrets-to-complex-intelligence/


Results imply creative people are 25% more likely to carry genes that raise risk of bipolar disorder and schizophrenia. But others argue the evidence is flimsy.

The ancient Greeks were first to make the point. Shakespeare raised the prospect too. But Lord Byron was, perhaps, the most direct of them all: “We of the craft are all crazy,” he told the Countess of Blessington, casting a wary eye over his fellow poets.

The notion of the tortured artist is a stubborn meme. Creativity, it states, is fuelled by the demons that artists wrestle in their darkest hours. The idea is fanciful to many scientists. But a new study claims the link may be well-founded after all, and written into the twisted molecules of our DNA.

In a large study published on Monday, scientists in Iceland report that genetic factors that raise the risk of bipolar disorder and schizophrenia are found more often in people in creative professions. Painters, musicians, writers and dancers were, on average, 25% more likely to carry the gene variants than professions the scientists judged to be less creative, among which were farmers, manual labourers and salespeople.

Kari Stefansson, founder and CEO of deCODE, a genetics company based in Reykjavik, said the findings, described in the journal Nature Neuroscience, point to a common biology for some mental disorders and creativity. “To be creative, you have to think differently,” he told the Guardian. “And when we are different, we have a tendency to be labelled strange, crazy and even insane.”

The scientists drew on genetic and medical information from 86,000 Icelanders to find genetic variants that doubled the average risk of schizophrenia, and raised the risk of bipolar disorder by more than a third. When they looked at how common these variants were in members of national arts societies, they found a 17% increase compared with non-members.

The researchers went on to check their findings in large medical databases held in the Netherlands and Sweden. Among these 35,000 people, those deemed to be creative (by profession or through answers to a questionnaire) were nearly 25% more likely to carry the mental disorder variants.

Stefansson believes that scores of genes increase the risk of schizophrenia and bipolar disorder. These may alter the ways in which many people think, but in most people do nothing very harmful. But for 1% of the population, genetic factors, life experiences and other influences can culminate in problems, and a diagnosis of mental illness.

“Often, when people are creating something new, they end up straddling between sanity and insanity,” said Stefansson. “I think these results support the old concept of the mad genius. Creativity is a quality that has given us Mozart, Bach, Van Gogh. It’s a quality that is very important for our society. But it comes at a risk to the individual, and 1% of the population pays the price for it.”

Stefansson concedes that his study found only a weak link between the genetic variants for mental illness and creativity. And it is this that other scientists pick up on. The genetic factors that raise the risk of mental problems explained only about 0.25% of the variation in peoples’ artistic ability, the study found. David Cutler, a geneticist at Emory University in Atlanta, puts that number in perspective: “If the distance between me, the least artistic person you are going to meet, and an actual artist is one mile, these variants appear to collectively explain 13 feet of the distance,” he said.

Most of the artist’s creative flair, then, is down to different genetic factors, or to other influences altogether, such as life experiences, that set them on their creative journey.

For Stefansson, even a small overlap between the biology of mental illness and creativity is fascinating. “It means that a lot of the good things we get in life, through creativity, come at a price. It tells me that when it comes to our biology, we have to understand that everything is in some way good and in some way bad,” he said.

But Albert Rothenberg, professor of psychiatry at Harvard University is not convinced. He believes that there is no good evidence for a link between mental illness and creativity. “It’s the romantic notion of the 19th century, that the artist is the struggler, aberrant from society, and wrestling with inner demons,” he said. “But take Van Gogh. He just happened to be mentally ill as well as creative. For me, the reverse is more interesting: creative people are generally not mentally ill, but they use thought processes that are of course creative and different.”

If Van Gogh’s illness was a blessing, the artist certainly failed to see it that way. In one of his last letters, he voiced his dismay at the disorder he fought for so much of his life: “Oh, if I could have worked without this accursed disease – what things I might have done.”

In 2014, Rothernberg published a book, “Flight of Wonder: an investigation of scientific creativity”, in which he interviewed 45 science Nobel laureates about their creative strategies. He found no evidence of mental illness in any of them. He suspects that studies which find links between creativity and mental illness might be picking up on something rather different.

“The problem is that the criteria for being creative is never anything very creative. Belonging to an artistic society, or working in art or literature, does not prove a person is creative. But the fact is that many people who have mental illness do try to work in jobs that have to do with art and literature, not because they are good at it, but because they’re attracted to it. And that can skew the data,” he said. “Nearly all mental hospitals use art therapy, and so when patients come out, many are attracted to artistic positions and artistic pursuits.”

http://www.theguardian.com/science/2015/jun/08/new-study-claims-to-find-genetic-link-between-creativity-and-mental-illness

In an ethically charged first, Chinese researchers have used gene editing to modify human embryos obtained from an in-vitro fertilization clinic.

The 16-person scientific team, based at the Sun Yat-Sen University in Guangzhou, China, set out to see whether it could correct the gene defect that causes beta-thalassemia, a blood disease, by editing the DNA of fertilized eggs.

The team’s report showed the method is not yet very accurate, confirming scientific doubts around whether gene editing could be practical in human embryos, and whether genetically engineered people are going to be born anytime soon.

The authors’ report appeared on April 18 in a low-profile scientific journal called Protein & Cell. The authors, led by Junjiu Huang, say there is a “pressing need” to improve the accuracy of gene editing before it can be applied clinically, for instance to produce children with repaired genes.

The team did not try to establish a pregnancy and say for ethical reasons they did their tests only in embryos that were abnormal.

“These authors did a very good job pointing out the challenges,” says Dieter Egli, a researcher at the New York Stem Cell Foundation in Manhattan. “They say themselves this type of technology is not ready for any kind of application.”

The paper had previously circulated among researchers and had provoked concern by highlighting how close medical science may be to tinkering with the human gene pool.

n March, an industry group called for a complete moratorium on experiments of the kind being reported from China, citing risks and the chance they would open the door to eugenics, or changing nonmedical traits in embryos, such as stature or intelligence.

Other scientists recommended high-level meetings of experts, regulators, and ethicists to debate if there are acceptable uses for such engineering.

The Chinese team reported editing the genes of more than 80 embryos using a technology called CRISPR-Cas9. While in some cases they were successful, in others the CRISPR technology didn’t work or introduced unexpected mutations. Some of the embryos ended up being mosaics, with a repaired gene in some cells, but not in others.

Parents who are carriers of beta-thalassemia could choose to test their IVF embryos, selecting those that have not inherited the disease-causing mutation. However, gene editing opens the possibility of germline modification, or permanently repairing the gene in an embryo, egg, or sperm in a way that is passed onto the offspring and to future generations.

That idea is the subject of intense debate, since some think the human gene pool is sacrosanct and should never be the subject of technological alteration, even for medical reasons. Others allow that germline engineering might one day be useful, but needs much more testing. “You can’t discount it,” says Egli. “It’s very interesting.”

The Chinese team performed the gene editing in eggs that had been fertilized in an IVF clinic but were abnormal because they had been fertilized by two sperm, not one. “Ethical reasons precluded studies of gene editing in normal embryos,” they said.

Abnormal embryos are widely available for research, both in China and the U.S. At least one U.S. genetics center is also using CRISPR in abnormal embryos rejected by IVF clinics. That group described aspects of its work on the condition that it would not be identified, since the procedure remains controversial.

Making repairs using CRISPR harnesses a cell’s own DNA repair machinery to correct genes. The technology guides a cutting protein to a particular site on the DNA molecule, chopping it open. If a DNA “repair template” is provided—in this case a correct version of the beta-globin gene—the DNA will mend itself using the healthy sequence.

The Chinese group says that among the problems they encountered, the embryo sometimes ignored the template, and instead repaired itself using similar genes from its own genome, “leading to untoward mutations.”

Huang said he stopped the research after the poor results. “If you want to do it in normal embryos, you need to be close to 100 percent,” Huang told Nature News. “That’s why we stopped. We still think it’s too immature.”

http://www.technologyreview.com/news/536971/chinese-team-reports-gene-editing-human-embryo/

Thanks to Michael Moore for bringing this to the It’s Interesting community.

There’s always the Magic 8 Ball, but when it comes to determining life expectancy, some people want a little more scientific help. Thankfully, there are some useful tests and calculators to help us figure out how many more years we have left — at least until the Fountain of Youth is available in pill form. With that in mind, here are six ways to help predict whether you should keep on working and paying the mortgage or just blow it all on a big beach vacation.

Treadmill test
Want to know if you’ll survive the decade? Hop on a treadmill. Johns Hopkins researchers analyzed more than 58,000 stress tests and concluded that the results of a treadmill test can predict survival over the next 10 years. They came up with a formula, called the FIT Treadmill Score, which helps use fitness to predict mortality.

“The notion that being in good physical shape portends lower death risk is by no means new, but we wanted to quantify that risk precisely by age, gender and fitness level, and do so with an elegantly simple equation that requires no additional fancy testing beyond the standard stress test,” says lead investigator Haitham Ahmed, M.D. M.P.H., a cardiology fellow at the Johns Hopkins University School of Medicine.

In addition to age and gender, the formula factors in your ability to tolerate physical exertion — measured in “metabolic equivalents” or METs. Slow walking equals two METs, while running equals eight.

Researchers used the most common treadmill test, called the Bruce Protocol. The test utilizes three-minute segments, starting at 1.7 mph and a 10 percent grade, which slowly increase in speed and grade.

Researchers analyzed information on the thousands of people ages 18 to 96 who took the treadmill test. They tracked down how many of them died for whatever reason over the next decade. They found that fitness level, as measured by METs and peak heart rate reached during exercise, were the best predictors of death and survival, even after accounting for important variables such as diabetes and family history of premature death.

Sitting test
You don’t need special equipment for this adult version of crisscross applesauce that uses flexibility, balance and strength to measure life expectancy. Brazilian physician Claudio Gil Araujo created the test when he noticed many of his older patients had trouble picking things up off the floor or getting out of a chair.

To try, start by standing upright in the middle of a room. Without using your arms or hands for balance, carefully squat into a cross-legged sitting position. Once you’re settled, stand up from the sitting position — again, without using your arms for help.

You can earn up to 10 points for this maneuver. You get five points for sitting, five for standing, and you subtract a point each time you use an arm or knee for leverage or 1/2 point any time you lose your balance or the movement gets clumsy.

The test seems fairly simple, but Araujo found that it was an accurate predictor of life expectancy. He tested it on more than 2,000 of his patients age 51 to 80, and found that those who scored fewer than eight points were twice as likely to die within the next six years. Those who scored three points or even lower were five times more likely to die within the same time frame.

Araujo didn’t have anyone under 50 try the test, so the results won’t mean the same if you’re younger. As MNN’s Bryan Nelson writes, “If you’re younger than 50 and have trouble with the test, it ought to be a wake-up call. The good news is that the younger you are, the more time you have to get into better shape.”

Test your telomeres

A simple test may help determine your “biological age” by measuring the length of your telomeres. Telomeres are protective sections of DNA located at the end of your chromosomes. They’re sometimes compared to the plastic tips of shoelaces that keep the laces from fraying.

Each time a cell replicates, the telomeres become shorter. Some researchers believe that lifespan can be roughly predicted based upon how long your telomeres are. Shorter telomeres hint at a shorter lifespan for cells. Longer telomeres may mean you have more cell replications left.

Originally offered a few years ago only as an expensive — and relatively controversial — blood test in Britain, telomere testing in now available all over the world, and some companies even test using saliva. The results tell you where your telomere lengths fall in relation to other participants your age.

The link between genetics and longevity has been so embraced that testing companies have since been founded by respected scientists and researchers including Nobel laureate Elizabeth Blackburn of UC San Francisco and George Church, director of Harvard University’s Molecular Technology Group.

The increase in the number of at-home tests is getting the attention of concerned federal regulators and other researchers who question whether the science should stay in the lab.

“It is worth doing. It does tell us something. It is the best measure we have” of cellular aging, aging-researcher and Genescient CEO Bryant Villeponteau told the San Jose Mercury News. But testing still belongs in a research setting, he said, not used as a personal diagnostic tool.

As more people take them, he said, “I think the tests will get better, with more potential to learn something.”

Grip strength

Do you have an iron handshake or a limp fish grasp? Your grip strength can be an indicator of your longevity.

Recent research has shown a link between grip strength and your biological age. Hand-grip strength typically decreases as you age, although many studies have shown links between stronger grip strength and increased mortality.

You can keep your grip strong by doing regular hand exercises such as slowly squeezing and holding a tennis or foam ball, then repeating several more times.

Take a sniff

Does every little smell bug you? People who wear too much perfume? Grilled fish in the kitchen? A sensitive sense of smell is good news for your lifespan.

In a study last fall, University of Chicago researchers asked more than 3,000 people to identify five different scents. The found that 39 percent of the study subjects who failed the smelling test died within five years, compared to 19 percent of those with moderate smell loss and just 10 percent of those with a healthy sense of smell.

“We think loss of the sense of smell is like the canary in the coal mine,” said the study’s lead author Jayant M. Pinto, M.D., an associate professor of surgery at the University of Chicago who specializes in the genetics and treatment of olfactory and sinus disease. “It doesn’t directly cause death, but it’s a harbinger, an early warning that something has gone badly wrong, that damage has been done. Our findings could provide a useful clinical test, a quick and inexpensive way to identify patients most at risk.”

Life expectancy calculator

There are many online calculators that can serve up you estimated last birthday — thanks to some fancy algorithms. Some only take into account a few simple factors such as your age, height and weight. The better ones consider a range of variables including family health history, diet and exercise practices, marital and education status, smoking, drinking and sex habits, and even where you live.

Enter as much data as you can into an online form, like this one from researchers at the University of Pennsylvania, and click to get your results: http://gosset.wharton.upenn.edu/mortality/perl/CalcForm.html

Read more: http://www.mnn.com/health/fitness-well-being/stories/6-tools-to-help-predict-how-long-youll-live#ixzz3WScKjbUW