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Javier E

Scientists Seek Ban on Method of Editing the Human Genome - NYTimes.com - 1 views

  • A group of leading biologists on Thursday called for a worldwide moratorium on use of a new genome-editing technique that would alter human DNA in a way that can be inherited.
  • The biologists fear that the new technique is so effective and easy to use that some physicians may push ahead before its safety can be assessed. They also want the public to understand the ethical issues surrounding the technique, which could be used to cure genetic diseases, but also to enhance qualities like beauty or intelligence. The latter is a path that many ethicists believe should never be taken.
  • a technique invented in 2012 makes it possible to edit the genome precisely and with much greater ease. The technique has already been used to edit the genomes of mice, rats and monkeys, and few doubt that it would work the same way in people.
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  • The technique holds the power to repair or enhance any human gene. “It raises the most fundamental of issues about how we are going to view our humanity in the future and whether we are going to take the dramatic step of modifying our own germline and in a sense take control of our genetic destiny, which raises enormous peril for humanity,”
  • The paper’s authors, however, are concerned about countries that have less regulation in science. They urge that “scientists should avoid even attempting, in lax jurisdictions, germline genome modification for clinical application in humans” until the full implications “are discussed among scientific and governmental organizations.”
  • Though such a moratorium would not be legally enforceable and might seem unlikely to exert global influence, there is a precedent. In 1975, scientists worldwide were asked to refrain from using a method for manipulating genes, the recombinant DNA technique, until rules had been established.
  • Though highly efficient, the technique occasionally cuts the genome at unintended sites. The issue of how much mistargeting could be tolerated in a clinical setting is one that Dr. Doudna’s group wants to see thoroughly explored before any human genome is edited.
  • “We worry about people making changes without the knowledge of what those changes mean in terms of the overall genome,” Dr. Baltimore said. “I personally think we are just not smart enough — and won’t be for a very long time — to feel comfortable about the consequences of changing heredity, even in a single individual.”
  • Many ethicists have accepted the idea of gene therapy, changes that die with the patient, but draw a clear line at altering the germline, since these will extend to future generations. The British Parliament in February approved the transfer of mitochondria, small DNA-containing organelles, to human eggs whose own mitochondria are defective. But that technique is less far-reaching because no genes are edited.
  • There are two broad schools of thought on modifying the human germline, said R. Alta Charo, a bioethicist at the University of Wisconsin and a member of the Doudna group. One is pragmatic and seeks to balance benefit and risk. The other “sets up inherent limits on how much humankind should alter nature,” she said. Some Christian doctrines oppose the idea of playing God, whereas in Judaism and Islam there is the notion “that humankind is supposed to improve the world.” She described herself as more of a pragmatist, saying, “I would try to regulate such things rather than shut a new technology down at its beginning.
  • The Doudna group calls for public discussion, but is also working to develop some more formal process, such as an international meeting convened by the National Academy of Sciences, to establish guidelines for human use of the genome-editing technique.“We need some principled agreement that we want to enhance humans in this way or we don’t,” Dr. Jaenisch said. “You have to have this discussion because people are gearing up to do this.”
Ellie McGinnis

The Mammoth Cometh - NYTimes.com - 2 views

  • Brand helped to establish in 1996 to support projects designed to inspire “long-term responsibility.”
  • The theme of the talk was “Is Mass Extinction of Life on Earth Inevitable?”
  • the resurrection of extinct species, like the woolly mammoth, aided by new genomic technologies developed by the Harvard molecular biologist George Church.
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  • Just as the loss of a species decreases the richness of an ecosystem, the addition of new animals could achieve the opposite effect.
  • National Geographic Society hosted a larger conference to debate the scientific and ethical questions raised by the prospect of “de-extinction.
  • “De-extinction went from concept to potential reality right before our eyes,
  • “This may be the biggest attraction and possibly the biggest benefit of de-extinction. It would surely be very cool to see a living woolly mammoth.”
  • less scientific, if more persuasive, argument was advanced by the ethicist Hank Greely and the law professor Jacob Sherkow, both of Stanford. De-extinction should be pursued, they argued in a paper published in Science, because it would be really
  • They will replace chunks of band-tailed-pigeon DNA with synthesized chunks of passenger-pigeon DNA, until the cell’s genome matches their working passenger-pigeon genome.
  • Scientists predict that changes made by human beings to the composition of the atmosphere could kill off a quarter of the planet’s mammal species, a fifth of its reptiles and a sixth of its birds by 2050
  • This cloning method, called somatic cell nuclear transfer, can be used only on species for which we have cellular material.
  • There is a shortcut. The genome of a closely related species will have a high proportion of identical DNA, so it can serve as a blueprint, or “scaffold.”
  • By comparing the fragments of passenger-pigeon DNA with the genomes of similar species, researchers can assemble an approximation of an actual passenger-pigeon genome.
  • “We’ve framed it in terms of conservation,”
  • the genome will have to be inscribed into a living cell.
  • As with any translation, there may be errors of grammar, clumsy phrases and perhaps a few missing passages, but the book will be legible. It should, at least, tell a good story.
  • MAGE (Multiplex Automated Genome Engineering). MAGE is nicknamed the “evolution machine” because it can introduce the equivalent of millions of years of genetic mutations within minutes
  • Developmental and behavioral biologists would take over, just in time to answer some difficult questions. Chicks imitate their parents’ behavior. How do you raise a passenger pigeon without parents of its own species? And how do you train band-tailed pigeons to nurture the strange spawn that emerge from their eggs; chicks that, to them, might seem monstrous: an avian Rosemary’s Baby?
  • For endangered species with tiny populations, scientists would introduce genetic diversity to offset inbreeding.
  • They will try to alter the birds’ diets, migration habits and environment. The behavior of each subsequent generation will more closely resemble that of their genetic cousins.
  • “There’s always this fear that somehow, if we do it, we’re going to accidentally make something horrible, because only nature can really do it right. But nature is totally random. Nature makes monsters. Nature makes threats. Many of the things that are most threatening to us are a product of nature. Revive & Restore is not going to tip the balance in any way.”
  • For species threatened by contagion, an effort would be made to fortify their DNA with genes that make them disease-resistant
  • This optimistic, soft-focus fantasy of de-extinction, while thrilling to Ben Novak, is disturbing to many conservation biologists, who consider it a threat to their entire discipline and even to the environmental movement.
  • The first question posed by conservationists addresses the logic of bringing back an animal whose native habitat has disappeared. Why go through all the trouble just to have the animal go extinct all over again?
  • There is also anxiety about disease
  • “If you recreate a species genetically and release it, and that genotype is based on a bird from a 100-year-old environment, you probably will increase risk.”
  • The scientific term for this type of genetic intervention is “facilitated adaptation.”
  • De-extinction also poses a rhetorical threat to conservation biologists. The specter of extinction has been the conservation movement’s most powerful argument. What if extinction begins to be seen as a temporary inconvenience?
  • De-extinction suggests that we can technofix our way out of environmental issues generally, and that’s very, very bad.
  • How will we decide which species to resurrect?
  • Philip Seddon recently published a 10-point checklist to determine the suitability of any species for revival, taking into account causes of its extinction, possible threats it might face upon resurrection and man’s ability to destroy the species “in the event of unacceptable ecological or socioeconomic impacts.”
  • But the most visceral argument against de-extinction is animal cruelty.
  • “Is it fair to do this to these animals?” Shapiro asked. “Is ‘because we feel guilty’ a good-enough reason?” Stewart Brand made a utilitarian counterargument: “We’re going to go through some suffering, because you try a lot of times, and you get ones that don’t take. On the other hand, if you can bring bucardos back, then how many would get to live that would not have gotten to live?”
  • In “How to Permit Your Mammoth,” published in The Stanford Environmental Law Journal, Norman F. Carlin asks whether revived species should be protected by the Endangered Species Act or regulated as a genetically modified organism.
  • He concludes that revived species, “as products of human ingenuity,” should be eligible for patenting.
  • The term “de-extinction” is misleading. Passenger pigeons will not rise from the grave
  • Our understanding of the passenger pigeon’s behavior derives entirely from historical accounts.
  • There is no authoritative definition of “species.” The most widely accepted definition describes a group of organisms that can procreate with one another and produce fertile offspring, but there are many exceptions.
  • Theseus’ ship, therefore, “became a standing example among the philosophers . . . one side holding that the ship remained the same, and the other contending that it was not the same.”
  • What is coming will go well beyond the resurrection of extinct species. For millenniums, we have customized our environment, our vegetables and our animals, through breeding, fertilization and pollination. Synthetic biology offers far more sophisticated tools. The creation of novel organisms, like new animals, plants and bacteria, will transform human medicine, agriculture, energy production and much else.
Javier E

The Selfish Gene turns 40 | Science | The Guardian - 0 views

  • The idea was this: genes strive for immortality, and individuals, families, and species are merely vehicles in that quest. The behaviour of all living things is in service of their genes hence, metaphorically, they are selfish.
  • Before this, it had been proposed that natural selection was honing the behaviour of living things to promote the continuance through time of the individual creature, or family, or group or species. But in fact, Dawkins said, it was the gene itself that was trying to survive, and it just so happened that the best way for it to survive was in concert with other genes in the impermanent husk of an individual
  • This gene-centric view of evolution also began to explain one of the oddities of life on Earth – the behaviour of social insects. What is the point of a drone bee, doomed to remain childless and in the service of a totalitarian queen? Suddenly it made sense that, with the gene itself steering evolution, the fact that the drone shared its DNA with the queen meant that its servitude guarantees not the individual’s survival, but the endurance of the genes they shar
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  • the subject is taught bafflingly minimally and late in the curriculum even today; evolution by natural selection is crucial to every aspect of the living world. In the words of the Russian scientist Theodosius Dobzhansky: “Nothing in biology makes sense except in the light of evolution.”
  • his true legacy is The Selfish Gene and its profound effect on multiple generations of scientists and lay readers. In a sense, The Selfish Gene and Dawkins himself are bridges, both intellectually and chronologically, between the titans of mid-century biology – Ronald Fisher, Trivers, Hamilton, Maynard Smith and Williams – and our era of the genome, in which the interrogation of DNA dominates the study of evolution.
  • Genes aren’t what they used to be either. In 1976 they were simply stretches of DNA that encoded proteins. We now know about genes made of DNA’s cousin, RNA; we’ve discovered genes that hop from genome to genome
  • Since 1976, our understanding of why life is the way it is has blossomed and changed. Once the gene became the dominant idea in biology in the 1990s there followed a technological goldrush – the Human Genome Project – to find them all.
  • None of the complications of modern genomes erodes the central premise of the selfish gene.
  • Much of the enmity stems from people misunderstanding that selfishness is being used as a metaphor. The irony of these attacks is that the selfish gene metaphor actually explains altruism. We help others who are not directly related to us because we share similar versions of genes with them.
  • In the scientific community, the chief objection maintains that natural selection can operate at the level of a group of animals, not solely on genes or even individuals
  • To my mind, and that of the majority of evolutionary biologists, the gene-centric view of evolution always emerges intact.
  • the premise remains exciting that a gene’s only desire is to reproduce itself, and that the complexity of genomes makes that reproduction more efficient.
catbclark

Is Most of Our DNA Garbage? - NYTimes.com - 0 views

  • Is Most of Our DNA Garbage?
  • Gregory believes that while some noncoding DNA is essential, most probably does nothing for us at all, and until recently, most biologists agreed with him.
  • Recent studies have revealed a wealth of new pieces of noncoding DNA that do seem to be as important to our survival as our more familiar genes.
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  • Large-scale surveys of the genome have led a number of researchers to expect that the human genome will turn out to be even more full of activity than previously thought.
  • “It was pretty much a case of hubris to imagine that we could dispense with any part of the genome — as if we knew enough to say it wasn’t functional.”
  • If every piece of the genome were essential, then many of those mutations would lead to significant birth defects, with the defects only multiplying over the course of generations; in less than a century, the species would become extinct.
  • “Much of what has been called ‘junk DNA’ in the human genome is actually a massive control panel with millions of switches regulating the activity of our genes.”
  • It’s no coincidence, researchers like Gregory argue, that bona fide creationists have used recent changes in the thinking about junk DNA to try to turn back the clock to the days before Darwin. (The recent studies on noncoding DNA “clearly demonstrate we are ‘fearfully and wonderfully made’ by our Creator God,” declared the Institute for Creation Research.)
  • Over millions of years, the human genome has spontaneously gotten bigger, swelling with useless copies of genes and new transposable elements.
tongoscar

What We Know Today about Coronavirus SARS-CoV-2 and Where Do We Go from Here - 0 views

  • The severe acute respiratory syndrome coronavirus SARS-CoV-2 (2019-nCoV) outbreak is an important reminder that the global community must strengthen national and international programs for early detection and response to future disease outbreaks.
  • Sequencing novel viruses helps remove the fear of the unknown by defining the viral genomic sequence for dissection and interpretation. While we are within the first two months of the first report to the World Health Organization (WHO) of SARS-CoV-21, and there remains much to learn, modern technology has identified and characterized the virus, sequenced its full genome, and started to describe the genetic evolution of the virus over a short time period.
  • On January 24, the first SARS-CoV-2 genome was published in the New England Journal of Medicine.2 To our knowledge, this is the first time a complete genome of a novel infectious agent has been publicly available in such a short time after the first case was reported to the WHO.
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  • As of February 7, over 80 SARS-CoV-2 genomes have been shared through the Global Initiative to Share All Influenza Data (GISAID) and GenBank, which will catalyze the research to understanding of the origin of the new virus, the epidemiology and transmission routes, and facilitate development of diagnostic and treatment strategies.3 Understanding the genome of SARS-CoV-2 early, provided unprecedented insight into dynamics of viral spread and impacted response strategies.
  • Within less than 60 days of reporting, global scientists know the likely origin of the virus, how similar it is to related viruses that are better understood, and what therapies may be applicable.
  • Analysis of the genomic information currently available, indicates SARS-CoV-2 is most closely related to a known bat SARS-like Coronavirus, indicating bats as the likely origin.
  • While this is early in the outbreak, there are no specific drugs available to treat SARS-CoV-2. There is high sequence conservation between SARS-CoV-2 and related SARS-CoV in viral drug targets, such as in protease and polymerase enzymes.
  • Reports from Africa indicate no positive cases of SARS-CoV-2 thus far. However, the lack of confirmed diagnoses may be due to a limited capacity for in-country testing rather than the true epidemiology of the virus.
Javier E

The Disease Detective - The New York Times - 1 views

  • What’s startling is how many mystery infections still exist today.
  • More than a third of acute respiratory illnesses are idiopathic; the same is true for up to 40 percent of gastrointestinal disorders and more than half the cases of encephalitis (swelling of the brain).
  • Up to 20 percent of cancers and a substantial portion of autoimmune diseases, including multiple sclerosis and rheumatoid arthritis, are thought to have viral triggers, but a vast majority of those have yet to be identified.
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  • Globally, the numbers can be even worse, and the stakes often higher. “Say a person comes into the hospital in Sierra Leone with a fever and flulike symptoms,” DeRisi says. “After a few days, or a week, they die. What caused that illness? Most of the time, we never find out. Because if the cause isn’t something that we can culture and test for” — like hepatitis, or strep throat — “it basically just stays a mystery.”
  • It would be better, DeRisi says, to watch for rare cases of mystery illnesses in people, which often exist well before a pathogen gains traction and is able to spread.
  • Based on a retrospective analysis of blood samples, scientists now know that H.I.V. emerged nearly a dozen times over a century, starting in the 1920s, before it went global.
  • Zika was a relatively harmless illness before a single mutation, in 2013, gave the virus the ability to enter and damage brain cells.
  • The beauty of this approach” — running blood samples from people hospitalized all over the world through his system, known as IDseq — “is that it works even for things that we’ve never seen before, or things that we might think we’ve seen but which are actually something new.”
  • In this scenario, an undiscovered or completely new virus won’t trigger a match but will instead be flagged. (Even in those cases, the mystery pathogen will usually belong to a known virus family: coronaviruses, for instance, or filoviruses that cause hemorrhagic fevers like Ebola and Marburg.)
  • And because different types of bacteria require specific conditions in order to grow, you also need some idea of what you’re looking for in order to find it.
  • The same is true of genomic sequencing, which relies on “primers” designed to match different combinations of nucleotides (the building blocks of DNA and RNA).
  • Even looking at a slide under a microscope requires staining, which makes organisms easier to see — but the stains used to identify bacteria and parasites, for instance, aren’t the same.
  • The practice that DeRisi helped pioneer to skirt this problem is known as metagenomic sequencing
  • Unlike ordinary genomic sequencing, which tries to spell out the purified DNA of a single, known organism, metagenomic sequencing can be applied to a messy sample of just about anything — blood, mud, seawater, snot — which will often contain dozens or hundreds of different organisms, all unknown, and each with its own DNA. In order to read all the fragmented genetic material, metagenomic sequencing uses sophisticated software to stitch the pieces together by matching overlapping segments.
  • The assembled genomes are then compared against a vast database of all known genomic sequences — maintained by the government-run National Center for Biotechnology Information — making it possible for researchers to identify everything in the mix
  • Traditionally, the way that scientists have identified organisms in a sample is to culture them: Isolate a particular bacterium (or virus or parasite or fungus); grow it in a petri dish; and then examine the result under a microscope, or use genomic sequencing, to understand just what it is. But because less than 2 percent of bacteria — and even fewer viruses — can be grown in a lab, the process often reveals only a tiny fraction of what’s actually there. It’s a bit like planting 100 different kinds of seeds that you found in an old jar. One or two of those will germinate and produce a plant, but there’s no way to know what the rest might have grown into.
  • Such studies have revealed just how vast the microbial world is, and how little we know about it
  • “The selling point for researchers is: ‘Look, this technology lets you investigate what’s happening in your clinic, whether it’s kids with meningitis or something else,’” DeRisi said. “We’re not telling you what to do with it. But it’s also true that if we have enough people using this, spread out all around the world, then it does become a global network for detecting emerging pandemics
  • One study found more than 1,000 different kinds of viruses in a tiny amount of human stool; another found a million in a couple of pounds of marine sediment. And most were organisms that nobody had seen before.
  • After the Biohub opened in 2016, one of DeRisi’s goals was to turn metagenomics from a rarefied technology used by a handful of elite universities into something that researchers around the world could benefit from
  • metagenomics requires enormous amounts of computing power, putting it out of reach of all but the most well-funded research labs. The tool DeRisi created, IDseq, made it possible for researchers anywhere in the world to process samples through the use of a small, off-the-shelf sequencer, much like the one DeRisi had shown me in his lab, and then upload the results to the cloud for analysis.
  • he’s the first to make the process so accessible, even in countries where lab supplies and training are scarce. DeRisi and his team tested the chemicals used to prepare DNA for sequencing and determined that using as little as half the recommended amount often worked fine. They also 3-D print some of the labs’ tools and replacement parts, and offer ongoing training and tech support
  • The metagenomic analysis itself — normally the most expensive part of the process — is provided free.
  • But DeRisi’s main innovation has been in streamlining and simplifying the extraordinarily complex computational side of metagenomics
  • IDseq is also fast, capable of doing analyses in hours that would take other systems weeks.
  • “What IDseq really did was to marry wet-lab work — accumulating samples, processing them, running them through a sequencer — with the bioinformatic analysis,”
  • “Without that, what happens in a lot of places is that the researcher will be like, ‘OK, I collected the samples!’ But because they can’t analyze them, the samples end up in the freezer. The information just gets stuck there.”
  • Meningitis itself isn’t a disease, just a description meaning that the tissues around the brain and spinal cord have become inflamed. In the United States, bacterial infections can cause meningitis, as can enteroviruses, mumps and herpes simplex. But a high proportion of cases have, as doctors say, no known etiology: No one knows why the patient’s brain and spinal tissues are swelling.
  • When Saha and her team ran the mystery meningitis samples through IDseq, though, the result was surprising. Rather than revealing a bacterial cause, as expected, a third of the samples showed signs of the chikungunya virus — specifically, a neuroinvasive strain that was thought to be extremely rare. “At first we thought, It cannot be true!” Saha recalls. “But the moment Joe and I realized it was chikungunya, I went back and looked at the other 200 samples that we had collected around the same time. And we found the virus in some of those samples as well.”
  • Until recently, chikungunya was a comparatively rare disease, present mostly in parts of Central and East Africa. “Then it just exploded through the Caribbean and Africa and across Southeast Asia into India and Bangladesh,” DeRisi told me. In 2011, there were zero cases of chikungunya reported in Latin America. By 2014, there were a million.
  • Chikungunya is a mosquito-borne virus, but when DeRisi and Saha looked at the results from IDseq, they also saw something else: a primate tetraparvovirus. Primate tetraparvoviruses are almost unknown in humans, and have been found only in certain regions. Even now, DeRisi is careful to note, it’s not clear what effect the virus has on people. “Maybe it’s dangerous, maybe it isn’t,” DeRisi says. “But I’ll tell you what: It’s now on my radar.
  • it reveals a landscape of potentially dangerous viruses that we would otherwise never find out about. “What we’ve been missing is that there’s an entire universe of pathogens out there that are causing disease in humans,” Imam notes, “ones that we often don’t even know exist.”
  • “The plan was, Let’s let researchers around the world propose studies, and we’ll choose 10 of them to start,” DeRisi recalls. “We thought we’d get, like, a couple dozen proposals, and instead we got 350.”
  • Metagenomic sequencing is especially good at what scientists call “environmental sampling”: identifying, say, every type of bacteria present in the gut microbiome, or in a teaspoon of seawater.
  • “When you draw blood from someone who has a fever in Ghana, you really don’t know very much about what would normally be in their blood without fever — let alone about other kinds of contaminants in the environment. So how do you interpret the relevance of all the things you’re seeing?”
  • Such criticisms have led some to say that metagenomics simply isn’t suited to the infrastructure of developing countries. Along with the problem of contamination, many labs struggle to get the chemical reagents needed for sequencing, either because of the cost or because of shipping and customs holdups
  • we’re less likely to be caught off-guard. “With Ebola, there’s always an issue: Where’s the virus hiding before it breaks out?” DeRisi explains. “But also, once we start sampling people who are hospitalized more widely — meaning not just people in Northern California or Boston, but in Uganda, and Sierra Leone, and Indonesia — the chance of disastrous surprises will go down. We’ll start seeing what’s hidden.”
Javier E

Ancient DNA Shows Humans Settled Caribbean in 2 Distinct Waves - The New York Times - 0 views

  • Before the advent of Caribbean genetic studies, archaeologists provided most of the clues about the origins of people in the region. The first human residents of the Caribbean appear to have lived mostly as hunter-gatherers, catching game on the islands and fishing at sea while also maintaining small gardens of crops.
  • Archaeologists have discovered a few burials of those ancient people. Starting in the early 2000s, geneticists managed to fish out a few tiny bits of preserved DNA in their bones. Significant advances in recent years have made it possible to pull entire genomes from ancient skeletons.
  • “We went from zero full genomes two years ago to over 200 now,”
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  • The genes of the oldest known residents of the Caribbean link them with the earliest populations that settled in Central and South America.
  • Part of the problem is that scientists have yet to find ancient DNA in the Caribbean that is more than 3,000 years old
  • The other problem is that ancient DNA is still scarce on the Caribbean coast of the mainland.
  • About 2,500 years ago, the archaeological record shows, there was a drastic shift in the cultural life of the Caribbean. People started living in bigger settlements, intensively farming crops like maize and sweet potatoes. Their pottery became more sophisticated and elaborate. For archaeologists, the change indicates the end of what they call the Archaic Age and the start of a Ceramic Age.
  • The skeletons from the Ceramic Age largely shared a new genetic signature. Their DNA links them to small tribes still living today in Colombia and Venezuela.
  • We don’t know a lot about these languages, although some words have managed to survive. Hurricane, for example, comes from hurakán, the Taino name for the god of storms.
  • The people bearing Ceramic Age ancestry came to dominate the Caribbean, with almost no interbreeding between the two groups.
  • These words bear a striking resemblance to words from a family of languages in South America called Arawak. The DNA of the Ceramic Age Caribbeans most closely resembles that of living Arawak speakers.
  • the new DNA findings had surprised him in many ways, giving him a host of new questions to investigate.
  • Over the course of the Ceramic Age, for example, strikingly new pottery styles emerged every few centuries. Researchers have long guessed that those shifts reflect the arrival of new groups of people in the islands. The ancient DNA doesn’t support that idea, though. There’s a genetic continuity through those drastic cultural changes. It appears that the same group of people in the Caribbean went through a series of major social changes that archaeologists have yet to explain.
  • Dr. Reich and his fellow geneticists also discovered family ties that spanned the Caribbean during the Ceramic Age. They found 19 pairs of people on different islands who shared identical segments of DNA — a sign that they were fairly close relatives. In one case, they found long-distance cousins from the Bahamas and Puerto Rico, separated by over 800 miles.
  • “The original idea was that people start in one place, they establish a colony someplace else, and then they just cut all ties to where they came from,” Dr. Keegan said. “But the genetic evidence is suggesting that these ties were maintained over a long period of time.”
  • Rather than being made up of isolated communities, in other words, the Caribbean was a busy, long-distance network that people regularly traveled by dugout canoe. “The water is like a highway,”
  • The genetic variations also allowed Dr. Reich and his colleague to estimate the size of the Caribbean society before European contact. Christopher Columbus’s brother Bartholomew sent letters back to Spain putting the figure in the millions
  • The DNA suggests that was an exaggeration: the genetic variations imply that the total population was as low as the tens of thousands.
  • now, with a population of about 44 million people, the Caribbean may contain more Taino DNA than it did in 1491.
  • Dr. Aviles and his colleagues have uploaded the ancient Caribbean genomes to a genealogical database called GEDMatch. With the help of genealogists, people can compare their own DNA to the ancient genomes. They can see the matching stretches of genetic material that reveal their relatedness.
lucieperloff

Ancient Dog DNA Shows Early Spread Around the Globe - The New York Times - 0 views

  • pins their likely origin to a group of extinct wolves.
  • pins their likely origin to a group of extinct wolves.
    • lucieperloff
       
      extinct?
  • Now an international team of researchers has sequenced and analyzed an additional 27 genomes of ancient dogs.
    • lucieperloff
       
      Where did they find the new genomes?
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  • that domestication probably began around 20,000 years ago.
  • much more diverse genetically than modern dogs.
  • All European dogs appear to have descended from one group of ancient European dogs, and the great modern diversity of dog shapes and sizes indicates an emphasis by breeders on certain very powerful genes.
    • lucieperloff
       
      European domesticated dogs came from ancient european dogs
  • Modern wolves, however, do show the incorporation of some dog DNA.
    • lucieperloff
       
      Wolf DNA is recessive?
  • The extraordinarily rich amount of information gathered from the 27 genomes provided many new perspectives on dog domestication and their association with humans.
  • even while they were sometimes breeding with wolves, no new wolf DNA entered their genomes.
  • Pigs can be a little wild but “if you’re a dog and you’ve got a little bit of wolf in you, that’s not a good thing and those things get knocked on the head very quickly or run away or disappear but they don’t get integrated into the dog population.”
    • lucieperloff
       
      Dogs with more wolf genes are less favorable - less common today
  • But then there was the sudden loss of diversity in dogs starting around 4,000 years ago.
  • The exact where and when of dog domestication remain unclear, and will never be pinned down to the kind of moment in time that dog owners like to imagine, but, in terms of a period of time and geographic area, Dr. Larson said, “We’re getting closer.”
    • lucieperloff
       
      No obvious answer to this question
Emily Horwitz

Scientists to Seek Clues to Violence in Genome of Gunman in Newtown, Conn. - NYTimes.com - 0 views

  • In a move likely to renew a longstanding ethical controversy, geneticists are quietly making plans to study the DNA of Adam Lanza, 20, who killed 20 children and seven adults in Newtown, Conn. Their work will be an effort to discover biological clues to extreme violence.
  • other experts speculated that the geneticists might look for mutations that might be associated with mental illnesses and ones that might also increase the risk for violence.
  • But whatever they do, this apparently is the first time researchers will attempt a detailed study of the DNA of a mass killer.
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  • Dr. Arthur Beaudet, a professor at the Baylor College of Medicine and the chairman of its department of molecular and human genetics, applaud the effort. He believes that the acts committed by men like Mr. Lanza and the gunmen in other rampages in recent years — at Columbine High School and in Aurora, Colo., in Norway, in Tucson and at Virginia Tech — are so far off the charts of normal behavior that there must be genetic changes driving them.
  • Everything known about mental illness, these skeptics say, argues that there are likely to be hundreds of genes involved in extreme violent behavior, not to mention a variety of environmental influences, and that all of these factors can interact in complex and unpredictable ways.
  • The National Institutes of Health was embroiled in controversy about 20 years ago simply for proposing to study the biological underpinnings of violence. Critics accused researchers of racism and singling out minorities, especially black men.
  • Studies of people at the far end of a bell curve can be especially informative, because the genetic roots of their conditions can be stark and easy to spot, noted J. H. Pate Skene, a Duke University neurobiologist. “I think doing research on outliers, people at an end of a spectrum on something of concern like violent behavior, is certainly a good idea,” he said, but he advised tempering expectations.
  • “If we know someone has a 2 percent chance or a 10 percent chance or a 20 percent chance of violent behavior, what would you do with that person?” Dr. Skene said. “They have not been convicted of anything — have not done anything wrong.”
  • Ultimately, understanding the genetics of violence might enable researchers to find ways to intervene before a person commits a horrific crime. But that goal would be difficult to achieve, and the pursuit of it risks jeopardizing personal liberties.
Emily Horwitz

New Genetic Twist: 4-Stranded DNA Lurks in Human Cells | LiveScience - 1 views

  • Sixty years after scientists described the chemical code of life — an interweaving double helix called DNA — researchers have found four-stranded DNA is also lurking in human cells.
  • they form in regions of deoxyribonucleic acid (DNA) that are full of guanine, one of the DNA molecule's four building blocks
  • Scientists had shown in the past that such quadruplex DNA could form in test tubes and had even been found in the cells of ciliated protozoa, or single-celled organisms with hairlike appendages. Also there were hints of its existence in human cells, though no direct proof, Lipps said.
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  • In the new study, researchers, including chemist Shankar Balasubramanian, of the University of Cambridge and Cambridge Research Institute, crafted antibody proteins specifically for this type of DNA. The proteins were marked with a fluorescent chemical, so when they hooked up to areas in the human genome packed with G-quadruplexes, they lit up.
  • Next, they incubated the antibodies with human cells in the lab, finding these structures tended to occur in genes of cells that were rapidly dividing, a telltale feature of cancer cells. They also found a spike in quadruplexes during the s-phase of the cell cycle, or the phase when DNA replicates just before the cell divides.
  • the researchers think the four-stranded DNA could be a target for personalized medicine in the future
  • "What makes me personally very happy about this work is that it again demonstrates that mechanisms first described in ciliated protozoa hold also true for other organisms up to human, demonstrating the strength of this model organism," wrote Lipps wrote.
oliviaodon

Why Are Some People So Smart? The Answer Could Spawn a Generation of Superbabies | WIRED - 0 views

  • use those machines to examine the genetic underpinnings of genius like his own. He wants nothing less than to crack the code for intelligence by studying the genomes of thousands of prodigies, not just from China but around the world.
  • fully expect they will succeed in identifying a genetic basis for IQ. They also expect that within a decade their research will be used to screen embryos during in vitro fertilization, boosting the IQ of unborn children by up to 20 points. In theory, that’s the difference between a kid who struggles through high school and one who sails into college.
  • studies make it clear that IQ is strongly correlated with the ability to solve all sorts of abstract problems, whether they involve language, math, or visual patterns. The frightening upshot is that IQ remains by far the most powerful predictor of the life outcomes that people care most about in the modern world. Tell me your IQ and I can make a decently accurate prediction of your occupational attainment, how many kids you’ll have, your chances of being arrested for a crime, even how long you’ll live.
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  • Dozens of popular books by nonexperts have filled the void, many claiming that IQ—which after more than a century remains the dominant metric for intelligence—predicts nothing important or that intelligence is simply too complex and subtle to be measured.
  • evidence points toward a strong genetic component in IQ. Based on studies of twins, siblings, and adoption, contemporary estimates put the heritability of IQ at 50 to 80 percent
  • intelligence has a genetic recipe
  • “Do you know any Perl?” Li asked him. Perl is a programming language often used to analyze genomic data. Zhao admitted he did not; in fact, he had no programming skills at all. Li handed him a massive textbook, Programming Perl. There were only two weeks left in the camp, so this would get rid of the kid for good. A few days later, Zhao returned. “I finished it,” he said. “The problems are kind of boring. Do you have anything harder?” Perl is a famously complicated language that takes university students a full year to learn.
  • So Li gave him a large DNA data set and a complicated statistical problem. That should do it. But Zhao returned later that day. “Finished.” Not only was it finished—and correct—but Zhao had even built a slick interface on top of the data.
  • driven by a fascination with kids who are born smart; he wants to know what makes them—and by extension, himself—the way they are.
  •  
    This is a really interesting article about using science to improve intelligence.
Javier E

untitled - 0 views

  • Scientists at Stanford University and the J. Craig Venter Institute have developed the first software simulation of an entire organism, a humble single-cell bacterium that lives in the human genital and respiratory tracts.
  • the work was a giant step toward developing computerized laboratories that could carry out many thousands of experiments much faster than is possible now, helping scientists penetrate the mysteries of diseases like cancer and Alzheimer’s.
  • cancer is not a one-gene problem; it’s a many-thousands-of-factors problem.”
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  • This kind of modeling is already in use to study individual cellular processes like metabolism. But Dr. Covert said: “Where I think our work is different is that we explicitly include all of the genes and every known gene function. There’s no one else out there who has been able to include more than a handful of functions or more than, say, one-third of the genes.”
  • The simulation, which runs on a cluster of 128 computers, models the complete life span of the cell at the molecular level, charting the interactions of 28 categories of molecules — including DNA, RNA, proteins and small molecules known as metabolites, which are generated by cell processes.
  • They called the simulation an important advance in the new field of computational biology, which has recently yielded such achievements as the creation of a synthetic life form — an entire bacterial genome created by a team led by the genome pioneer J. Craig Venter. The scientists used it to take over an existing cell.
  • A decade ago, scientists developed simulations of metabolism that are now being used to study a wide array of cells, including bacteria, yeast and photosynthetic organisms. Other models exist for processes like protein synthesis.
  • “Right now, running a simulation for a single cell to divide only one time takes around 10 hours and generates half a gigabyte of data,” Dr. Covert wrote. “I find this fact completely fascinating, because I don’t know that anyone has ever asked how much data a living thing truly holds. We often think of the DNA as the storage medium, but clearly there is more to it than that.”
  • scientists chose an approach called object-oriented programming, which parallels the design of modern software systems. Software designers organize their programs in modules, which communicate with one another by passing data and instructions back and forth.
  • “The major modeling insight we had a few years ago was to break up the functionality of the cell into subgroups, which we could model individually, each with its own mathematics, and then to integrate these submodels together into a whole,”
julia rhodes

The Little Bit of Neanderthal in All of Us - NYTimes.com - 0 views

  • Ever since the discovery in 2010 that Neanderthals interbred with the ancestors of living humans, scientists have been trying to determine how their DNA affects people today.
  • Among the findings, the studies have found clues to the evolution of skin and fertility, as well as susceptibility to diseases like diabetes. More broadly, they show how the legacy of Neanderthals has endured 30,000 years after their extinction.
  • By 2010 they had reconstructed most of the Neanderthal genome. When they compared it with the genomes of five living humans, they found similarities to small portions of the DNA in the Europeans and Asians.The researchers concluded that Neanderthals and modern humans must have interbred.
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  • “They’d be bumping into Neanderthals at every street corner,” he joked.
  • Both studies suggest that Neanderthal genes involved in skin and hair were favored by natural selection in humans. Today, they are very common in living non-Africans.
  • “We don’t understand enough about the biology of those particular genes yet,” he said. “It makes it hard to pinpoint a reason why they’re beneficial.”
  • “This experiment of nature has been done,” said Dr. Reich, “and we can study it.”
Sophia C

BBC News - Diabetes risk gene 'from Neanderthals' - 0 views

  • This means that Neanderthal genes are now scattered across the genomes of all non-Africans living today.
  • arry the higher risk version of the gene are 25% more likely to have diabetes than those who do not, and people who inherited copies from both parents are 50% more likely to have diabetes.
  • named SLC16A11 - has been found in up to half of people with recent Native American ancestry, including Latin Americans.
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  • Americans could account for as much as 20% of these populations' increased prevalence of type 2 diabetes - the origins of which are complex and poorly understood.
  • It is not unusual to find Neanderthal genes. About 2% of the genomes of present-day non-Africans were inherited from this distinctive human group, which lived across Europe and western Asia from about 400,000-300,000 years ago until 30,000 years ag
grayton downing

2013 Life Sciences Salary Survey | The Scientist Magazine® - 0 views

  • US researchers across academia, industry, and government earn an average of nearly $96,000 per year in total compensation, including base salary, bonuses, and other income, compared with a European average of just $66,700. Life scientists in Canada come in right in the middle, at $78,200, while researchers in India lag far behind, earning an average of just $11,200.
  • life sciences, could explain the oft-cited “brain drain,” which has seen foreign researchers flock to the U.S. in search of good jobs with ample compensation.
  • Across the globe, scientists earn a wide range of salaries, with US researchers earning nearly $96,000 total compensation per year while India lags far behind at less than $11,200, though this discrepancy is at least partly explained by the vast differences in cost of living in the two countries. Still, this enormous gulf is a strong driver of “brain drain
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  • Dramatic budget cuts in the past few years, however, may make US academia less of a paradise.
  • European salaries also lag behind those in the U.S., with the average European life scientist making anywhere from 41 to 82 percent of what the average American researcher earns.
  • Europe make around 50 percent of what full professors there make, postdocs in the U.S. earn less than a third of a professor’s salary.
  • Equal Pay Act prohibited unequal pay for men and women doing the same jobs. But salary disparities remain, including in the life sciences. “It is a persistent problem,” says Curtis. “It’s important for people to realize that there are continuing inequalities.” In this year’s survey, for example, male respondents in the U.S. reported an average total income of around $111,000 per year, while their female counterparts averaged just $77,000 in annual pay.
  • fewer women make it to high-level positions than men do, says Curtis.
  • life-science specialty is often tomorrow’s overcrowded field. Case in point: genomics versus genetics. Genomics relies heavily on bioinformatics, mathematics, and computational modeling
  • survey highlights the well-established discrepancy between industry and academic salaries. According to the data, life scientists in industry make around $136,000 per year, compared to average academic earnings of $85,000.
Javier E

I Had My DNA Picture Taken, With Varying Results - NYTimes.com - 0 views

  • Scientists have identified about 10 million SNPs within our three billion nucleotides. But an entire genome sequencing — looking at all three billion nucleotides — would cost around $3,000; the tests I took examined fewer than a million SNPs.
  • “Imagine if you took a book and you only looked at the first letter of every other page,” said Dr. Robert Klitzman, a bioethicist and professor of clinical psychiatry at Columbia. (I am a graduate student there in his Master of Bioethics program.) “You’re missing 99.9 percent of the letters that make the genome. The information is going to be limited.”
  • the major issue, experts say, is that the causes of most common diseases remain unknown. Genes account for just 5 to 20 percent of the whole picture.
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  • “Your results are not the least bit surprising,” he told me. “Anything short of sequencing is going to be short on accuracy — and even then, there’s almost no comprehensive data sets to compare to.”
  • “Even if they are accurately looking at 5 percent of the attributable risk, they’ve ignored the vast majority of the other risk factors — the dark matter for genetics — because we as a scientific community haven’t yet identified those risk factors,”
  • There are only 23 diseases that start in adulthood, can be treated, and for which highly predictive tests exist. All are rare, with hereditary breast cancer the most common. “A small percentage of people who get tested will get useful information,” Dr. Klitzman said. “But for most people, the results are not clinically useful, and they may be misleading or confusing.”
  • To be sure, my tests did provide some beneficial information. They all agreed that I lack markers associated with an increased risk of breast cancer and Alzheimer’s. That said, they were testing for only a small fraction of the genetic risks for these diseases, not for rare genetic variants that confer much of the risk. I could still develop those diseases, of course, but I don’t have reason to pursue aggressive screenings as I age.
  • He added: “If you want to spend money wisely to protect your health and you have a few hundred dollars, buy a scale, stand on it, and act accordingly.”
carolinewren

YaleNews | Yale researchers map 'switches' that shaped the evolution of the human brain - 0 views

  • Thousands of genetic “dimmer” switches, regions of DNA known as regulatory elements, were turned up high during human evolution in the developing cerebral cortex, according to new research from the Yale School of Medicine.
  • these switches show increased activity in humans, where they may drive the expression of genes in the cerebral cortex, the region of the brain that is involved in conscious thought and language. This difference may explain why the structure and function of that part of the brain is so unique in humans compared to other mammals.
  • Noonan and his colleagues pinpointed several biological processes potentially guided by these regulatory elements that are crucial to human brain development.
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  • “Building a more complex cortex likely involves several things: making more cells, modifying the functions of cortical areas, and changing the connections neurons make with each other
  • Scientists have become adept at comparing the genomes of different species to identify the DNA sequence changes that underlie those differences. But many human genes are very similar to those of other primates, which suggests that changes in the way genes are regulated — in addition to changes in the genes themselves — is what sets human biology apart.
  • First, Noonan and his colleagues mapped active regulatory elements in the human genome during the first 12 weeks of cortical development by searching for specific biochemical, or “epigenetic” modifications
  • same in the developing brains of rhesus monkeys and mice, then compared the three maps to identify those elements that showed greater activity in the developing human brain.
  • wanted to know the biological impact of those regulatory changes.
  • They used those data to identify groups of genes that showed coordinated expression in the cerebral cortex.
  • “While we often think of the human brain as a highly innovative structure, it’s been surprising that so many of these regulatory elements seem to play a role in ancient processes important for building the cortex in all mammals, said first author Steven Reilly
Javier E

Want to Boost the Economy? Invest in Science - NYTimes.com - 0 views

  • the longstanding bipartisan consensus on investing in science. With support from Congress, Mr. Clinton put research funding on a growth path, including a doubling over five years (completed under President George W. Bush) of the budget for the National Institutes of Health.
  • the $3.8 billion taxpayers invested in the Human Genome Project between 1988 and 2003 helped create and drive $796 billion in economic activity by industries that now depend on the advances achieved in genetics,
  • President Obama is proposing that the United States boost its overall national research and development investments — including private enterprise and academia as well as government — to 3 percent of gross domestic product — a number that would still lag behind Israel, Sweden, Japan and South Korea, in that order.
Megan Flanagan

The Big Search to Find Out Where Dogs Come From - The New York Times - 0 views

  • scientists are still debating exactly when and where the ancient bond originated
  • agree that they evolved from ancient wolves
  • he essence of the idea is that people actively bred wolves to become dogs just the way they now breed dogs to be tiny or large, or to herd sheep.
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  • Wolves are hard to tame, even as puppies, and many researchers find it much more plausible that dogs, in effect, invented themselves.
  • gradually evolved to become tamer and tamer, producing lots of offspring because of the relatively easy pickings
  • researchers question whether dogs experience feelings like love and loyalty, or whether their winning ways are just a matter of instincts that evolved because being a hanger-on is an easier way to make a living than running down elk.
  • dogs and wolves interbreed easily and some scientists are not convinced that the two are even different species
  • generally agree that there is good evidence that dogs were domesticated around 15,000 years ago
  • “Maybe dog domestication on some level kicks off this whole change in the way that humans are involved and responding to and interacting with their environment,
  • most dog breeds were invented in the 19th century during a period of dog obsession that he called “the giant whirlwind blender of the European crazy Victorian dog-breeding frenzy.
  • “There’s hardly a person working in canine genetics that’s not working on that project
  • Almost every group has a different origination hypothesis
  • jaws and occasionally nearly complete skulls from old and recent dogs, wolves and canids that could fall into either category.
  • will be able to determine whether the domestication process occurred closer to 15,000 or 30,000 years ago,
  • major achievement in the world of canine science, and a landmark in the analysis of ancient DNA to show evolution, migrations and descent,
  • based on DNA evidence and the shape of ancient skulls, that dog domestication occurred well over 30,000 years ago.
  • he became fed up with the lack of ancient DNA evidence in papers about the origin of dogs.
  • identified a skull about 32,000 years old from a Belgian cave in Goyet as an early dog.
  • arguing that the evidence just wasn’t there to call the Goyet skull a dog,
  • claims are controversial and is willing, like the rest of the world of canine science, to risk damage to the fossils themselves to get more information on not just the mitochondrial DNA but also the nuclear DNA.
  • geneticists try to establish is how different the DNA of one animal is from another. Adding ancient DNA gives many more points of reference over a long time span.
  • will be able to identify changes in the skulls or jaws of those wolves that show shifts to more doglike shapes, helping to narrow the origins of domestication
  • the project will publish a flagship paper from all of the participants describing their general findings
  • a group in China was forming with the goal of sequencing 10,000 dog genomes
  • growing increasingly confident that they will find what they want, and come close to settling the thorny question of when and where the tearing power of a wolf jaw first gave way to the persuasive force of a nudge from a dog’s cold nose.
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