Main Category: Genetics News
Article Date: 09 Dec 2007 - 10:00 PST
Are those inclined towards generosity genetically programmed to behave that way? A team of researchers, including Dr. Ariel Knafo of the Psychology Department at the Hebrew University of Jerusalem, believes that this could very well be the case.
Through an online task involving making a choice whether or not to give away money, the researchers found that those who chose to give away some or all of their money differed genetically from those involved in the exercise who chose not to give their money away.
The scientists conducted the experiment with 203 online "players". Each player could choose to keep the equivalent of $12 he was allocated, or to give all or part of it to an anonymous other player.
Those involved also provided DNA samples which were analyzed and compared to their reactions. It was found that those who had certain variants of a gene called AVPR1a gave on average nearly 50 percent more money than those not displaying that variant. The results of the study were published online recently in the research journal Genes, Brain and Behavior.
"The experiment provided the first evidence, to my knowledge, for a relationship between DNA variability and real human altruism," said Knafo, who conducted the research along with other researchers, including Prof. R. P. Ebstein, Prof. Gary Bornstein, and Salomon Israel of the Psychology Department at the Hebrew University of Jerusalem.
The gene AVPR1a codes for the production of a receptor that enables a hormone, arginine vasopressin, to act on brain cells. Vasopressin, in turn, has been implicated in social bonding. The researchers found greater altruism in players in which a key section of the AVPR1a gene, called its promoter, was longer. The promoter is the region of a gene that allows cellular machinery to bind to it and determine how much gene product is made. In the case of this gene, a longer promoter can result in greater activity.
The findings could help biologists sort out altruism's evolutionary history, according to the scientists. They noted that a version of AVPR1a also exists in rodents called voles, where it also promotes social bonding. This suggests that altruism has a long rooted genetic history, which may have taken on a new role during human evolution.
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Article adapted by Medical News Today from original press release.
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Sunday, December 9, 2007
Subliminal Smells Bias Preception About A Person's Likeability
ScienceDaily (Dec. 8, 2007) — Anyone who has bonded with a puppy madly sniffing with affection gets an idea of how scents, most not apparent to humans, are critical to a dog's appreciation of her two-legged friends. Now new research from Northwestern University suggests that humans also pick up infinitesimal scents that affect whether or not we like somebody. "We evaluate people every day and make judgments about who we like or don't like," said Wen Li, a post-doctoral fellow in the Cognitive Neurology and Alzheimer's Disease Center at Northwestern's Feinberg School of Medicine and lead author of the study. "We may think our judgments are based only on various conscious bits of information, but our senses also may provide subliminal perceptual information that affects our behavior."
Minute amounts of odors elicited salient psychological and physiological changes that suggest that humans get much more information from barely perceptible scents than previously realized.To test whether subliminal odors alter social preferences, participants were asked to sniff bottles with three different scents: lemon (good), sweat (bad) and ethereal (neutral). The scents ranged from levels that could be consciously smelled to those that were barely perceptible. Study participants were informed that an odor would be present in 75 percent of the trials.
Most participants were not aware of the barely perceptible odors. After sniffing from each of the bottles, they were shown a face with a neutral expression and asked to evaluate it using one of six different rankings, ranging from extremely likeable to extremely unlikeable.
People who were slightly better than average at figuring out whether the minimal smell was present didn't seem to be biased by the subliminal scents.
"The study suggests that people conscious of the barely noticeable scents were able to discount that sensory information and just evaluate the faces," Li said. "It only was when smell sneaked in without being noticed that judgments about likeability were biased."
The conclusions fit with recent studies using visual stimuli that suggest that top-down control mechanisms in the brain can be exerted on unconscious processing even though individuals have no awareness of what is being controlled.
Besides Li, the study's co-investigators include Isabel Moallem, Loyola University; Ken Paller, professor of psychology in the Weinberg College of Arts and Sciences at Northwestern; and Jay Gottfried, assistant professor of neurology at Feinberg and senior author of the paper.*
"When sensory input is insufficient to provoke a conscious olfactory experience, subliminal processing prevails and biases perception," Paller said. "But as the awareness of a scent increases, greater executive control in the brain is engaged to counteract unconscious olfaction."
The acute sensitivity of human olfaction tends to be underappreciated. "In general, people tend to be dismissive of human olfaction and discount the role that smell plays in our everyday life," said Gottfried. "Our study offers direct evidence that human social behavior is under the influence of miniscule amounts of odor, at concentrations too low to be consciously perceived, indicating that the human sense of smell is much keener than commonly thought."
The study adds to a growing body of research suggesting that subliminal sensory information -- whether from scents, vision or hearing -- affects perception. "We are beginning to understand more about how perception and memory function," Paller said, "by taking into account various types of influences that operate without our explicit knowledge."
*The paper "Subliminal Smells Can Guide Social Preferences" was published in the December issue of Psychological Science.
Adapted from materials provided by Northwestern University.
Minute amounts of odors elicited salient psychological and physiological changes that suggest that humans get much more information from barely perceptible scents than previously realized.To test whether subliminal odors alter social preferences, participants were asked to sniff bottles with three different scents: lemon (good), sweat (bad) and ethereal (neutral). The scents ranged from levels that could be consciously smelled to those that were barely perceptible. Study participants were informed that an odor would be present in 75 percent of the trials.
Most participants were not aware of the barely perceptible odors. After sniffing from each of the bottles, they were shown a face with a neutral expression and asked to evaluate it using one of six different rankings, ranging from extremely likeable to extremely unlikeable.
People who were slightly better than average at figuring out whether the minimal smell was present didn't seem to be biased by the subliminal scents.
"The study suggests that people conscious of the barely noticeable scents were able to discount that sensory information and just evaluate the faces," Li said. "It only was when smell sneaked in without being noticed that judgments about likeability were biased."
The conclusions fit with recent studies using visual stimuli that suggest that top-down control mechanisms in the brain can be exerted on unconscious processing even though individuals have no awareness of what is being controlled.
Besides Li, the study's co-investigators include Isabel Moallem, Loyola University; Ken Paller, professor of psychology in the Weinberg College of Arts and Sciences at Northwestern; and Jay Gottfried, assistant professor of neurology at Feinberg and senior author of the paper.*
"When sensory input is insufficient to provoke a conscious olfactory experience, subliminal processing prevails and biases perception," Paller said. "But as the awareness of a scent increases, greater executive control in the brain is engaged to counteract unconscious olfaction."
The acute sensitivity of human olfaction tends to be underappreciated. "In general, people tend to be dismissive of human olfaction and discount the role that smell plays in our everyday life," said Gottfried. "Our study offers direct evidence that human social behavior is under the influence of miniscule amounts of odor, at concentrations too low to be consciously perceived, indicating that the human sense of smell is much keener than commonly thought."
The study adds to a growing body of research suggesting that subliminal sensory information -- whether from scents, vision or hearing -- affects perception. "We are beginning to understand more about how perception and memory function," Paller said, "by taking into account various types of influences that operate without our explicit knowledge."
*The paper "Subliminal Smells Can Guide Social Preferences" was published in the December issue of Psychological Science.
Adapted from materials provided by Northwestern University.
Sickle Save: Skin cells fix anemia in mice
http://www.sciencenews.org/articles/20071208/fob1.asp
Sickle Save: Skin cells fix anemia in mice
Brian Vastag
Using a new technique to turn skin cells into stem cells, scientists have corrected sickle cell anemia in mice. The advance provides proof of principle that stem cells made without embryos can treat disease, at least in lab animals, says Rudolf Jaenisch, the biologist who led the work at the Whitehead Institute for Biomedical Research in Cambridge, Mass.
Jaenisch and his team caution, however, that the technique is not yet suitable for use in humans because it may cause tumors.
Still, Jaenisch says that embryofree stem cells now "have the same potential for therapy as embryonic stem cells, without the ethical and practical issues." Embryonic stem cells are difficult to obtain, and some people oppose such research because it destroys discarded embryos.
In the new work, the scientists turned skin cells into embryonic-like cells. Researchers at Kyoto University in Japan first developed the technique in mice and published the protocol last year. Last month, two teams repeated the feat with human cells (SN: 11/24/07, p. 323). All of these protocols deploy viruses carrying four master genes that turn back the clock on skin cells, making them look and act embryonic. Researchers call these new cells induced pluripotent stem (iPS) cells because they can form any tissue in the body.
The Whitehead researchers obtained mice engineered to carry a defective version of the human hemoglobin gene. That flaw distorts red blood cells into the characteristic sickle shape. To fix the flaw, the researchers induced skin cells plucked from the tails of the mice to become iPS cells, and corrected the genetic defect.
Next, the Whitehead team prodded the corrected cells into becoming blood stem cells, which can produce red and white blood cells. The team used a recipe originally developed for embryonic stem cells and found that it also made iPS cells grow into blood stem cells, the researchers report online Dec. 6 and in an upcoming Science.
"We wanted to compare the embryonic stem cells versus the iPS cells," says Whitehead researcher Jacob Hanna. "They behaved similarly."
Finally, the researchers performed a procedure akin to a bone marrow transplant. They transfused a million of the corrected blood stem cells into each of three mice whose bone marrow—which harbored the mice's original defective blood stem cells—had been obliterated by radiation. The corrected blood stem cells soon began producing healthy red blood cells. Because the same animal was both donor and recipient, the infused cells were not rejected, as commonly occurs in human bone marrow transplants.
After this treatment, the formerly lethargic mice made swift recoveries. "The improvement was profound," says Hanna. "There was a clear sign of reduction of destruction of red blood cells, which is actually the main problem in sickle cell anemia."
Mark Walters, a bone marrow transplant specialist at Children's Hospital and Research Center in Oakland, Calif., says the procedure surmounts the biggest obstacle in performing such transplants in children—finding a genetically matched donor. Worldwide, only 300 to 400 children with sickle cell anemia have received bone marrow transplants because matched siblings are rare. "But the results are outstanding, with a cure rate between 85 and 90 percent," Walters says.
Before the procedure can advance to human trials, though, researchers must find a more benign way to make iPS cells, because the viruses currently used can trigger cancer. "We'd have to have some information that these are not preleukemic or premalignant cells, that they're safe in the long term," says Walters.
Sickle Save: Skin cells fix anemia in mice
Brian Vastag
Using a new technique to turn skin cells into stem cells, scientists have corrected sickle cell anemia in mice. The advance provides proof of principle that stem cells made without embryos can treat disease, at least in lab animals, says Rudolf Jaenisch, the biologist who led the work at the Whitehead Institute for Biomedical Research in Cambridge, Mass.
Jaenisch and his team caution, however, that the technique is not yet suitable for use in humans because it may cause tumors.
Still, Jaenisch says that embryofree stem cells now "have the same potential for therapy as embryonic stem cells, without the ethical and practical issues." Embryonic stem cells are difficult to obtain, and some people oppose such research because it destroys discarded embryos.
In the new work, the scientists turned skin cells into embryonic-like cells. Researchers at Kyoto University in Japan first developed the technique in mice and published the protocol last year. Last month, two teams repeated the feat with human cells (SN: 11/24/07, p. 323). All of these protocols deploy viruses carrying four master genes that turn back the clock on skin cells, making them look and act embryonic. Researchers call these new cells induced pluripotent stem (iPS) cells because they can form any tissue in the body.
The Whitehead researchers obtained mice engineered to carry a defective version of the human hemoglobin gene. That flaw distorts red blood cells into the characteristic sickle shape. To fix the flaw, the researchers induced skin cells plucked from the tails of the mice to become iPS cells, and corrected the genetic defect.
Next, the Whitehead team prodded the corrected cells into becoming blood stem cells, which can produce red and white blood cells. The team used a recipe originally developed for embryonic stem cells and found that it also made iPS cells grow into blood stem cells, the researchers report online Dec. 6 and in an upcoming Science.
"We wanted to compare the embryonic stem cells versus the iPS cells," says Whitehead researcher Jacob Hanna. "They behaved similarly."
Finally, the researchers performed a procedure akin to a bone marrow transplant. They transfused a million of the corrected blood stem cells into each of three mice whose bone marrow—which harbored the mice's original defective blood stem cells—had been obliterated by radiation. The corrected blood stem cells soon began producing healthy red blood cells. Because the same animal was both donor and recipient, the infused cells were not rejected, as commonly occurs in human bone marrow transplants.
After this treatment, the formerly lethargic mice made swift recoveries. "The improvement was profound," says Hanna. "There was a clear sign of reduction of destruction of red blood cells, which is actually the main problem in sickle cell anemia."
Mark Walters, a bone marrow transplant specialist at Children's Hospital and Research Center in Oakland, Calif., says the procedure surmounts the biggest obstacle in performing such transplants in children—finding a genetically matched donor. Worldwide, only 300 to 400 children with sickle cell anemia have received bone marrow transplants because matched siblings are rare. "But the results are outstanding, with a cure rate between 85 and 90 percent," Walters says.
Before the procedure can advance to human trials, though, researchers must find a more benign way to make iPS cells, because the viruses currently used can trigger cancer. "We'd have to have some information that these are not preleukemic or premalignant cells, that they're safe in the long term," says Walters.
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