Posts tagged genes
Articles and news from the latest research reports.
Perfect Pitch: Knowing the Note May Be in Your Genes
People with perfect pitch seem to possess their own inner pitch pipe, allowing them to sing a specific note without first hearing a reference tone. This skill has long been associated with early and extensive musical training, but new research suggests that perfect pitch may have as much to do with genetics as it does with learning an instrument or studying voice.
Previous research does draw a connection between early musical training and the likelihood of a person developing perfect pitch, which is also referred to as absolute pitch. This is especially true among speakers of tonal languages, such as Mandarin. Speakers of English and other non-tonal languages are far less likely to develop perfect pitch, even if they were exposed to early and extensive musical training.
“We have wondered if perfect pitch is as much about nature or nurture,” said Diana Deutsch, a professor of psychology at the University of California, San Diego. “What is clear is that musically trained individuals who speak a non-tone language can acquire absolute pitch, but it is still a remarkably rare talent. What has been less clear is why most others with equivalent musical training do not.” Deutsch and her colleague Kevin Dooley present their findings at the 164th meeting of the Acoustical Society of America (ASA), held Oct. 22 – 26 in Kansas City, Missouri.
To shine light on this question, the researchers studied 27 English speaking adults, 7 of whom possessed perfect pitch. All began extensive musical training at or before the age of 6. The researchers tested the subjects’ memory ability using a test known as the digit span, which measures how many digits a person can hold in memory and immediately recall in correct order. They presented the digits either visually or auditorily; for the auditory test, the subject listened to the numbers through headphones, and for the visual test the digits were presented successively at the center of a computer screen.
The people with perfect pitch substantially outperformed the others in the audio portion of the test. In contrast, for the visual test, the two groups exhibited very similar performance, and their scores were not significantly different from each other. This is significant because other researchers have shown previously that auditory digit span has a genetic component.
“Our finding therefore shows that perfect pitch is associated with an unusually large memory span for speech sounds,” said Deutsch, “which in turn could facilitate the development of associations between pitches and their spoken languages early in life.”
(Source: newswise.com)
Evolution of new genes captured
Like job-seekers searching for a new position, living things sometimes have to pick up a new skill if they are going to succeed. Researchers from the University of California, Davis, and Uppsala University, Sweden, have shown for the first time how living organisms do this.
The observation, published Oct. 19 in the journal Science, closes an important gap in the theory of natural selection.
Scientists have long wondered how living things evolve new functions from a limited set of genes. One popular explanation is that genes duplicate by accident; the duplicate undergoes mutations and picks up a new function; and, if that new function is useful, the gene spreads.
"It’s an old idea and it’s clear that this happens," said John Roth, a distinguished professor of microbiology at UC Davis and co-author of the paper.
The problem, Roth said, is that it has been hard to imagine how it occurs. Natural selection is relentlessly efficient in removing mutated genes: Genes that are not positively selected are quickly lost.
How then does a newly duplicated gene stick around long enough to pick up a useful new function that would be a target for positive selection?
Experiments in Roth’s laboratory and elsewhere led to a model for the origin of a novel gene by a process of “innovation, amplification and divergence.” This model has now been tested by Joakim Nasvall, Lei Sun and Dan Andersson at Uppsala.
Decreased Gene Activity Is Likely Involved in Childhood Risk for Anxiety and Depression
Decreased activity of a group of genes may explain why in young children the “fear center” of the anxious brain can’t learn to distinguish real threats from the imaginary, according to a new University of Wisconsin study.
The study, published this week in the Proceedings of the National Academy of Sciences (PNAS), lays out evidence that young primates with highly anxious temperaments have decreased activity of specific genes within the amygdala, the brain’s fear center.
The authors hypothesize that this may result in over activity of the brain circuit that leads to higher risk for developing disabling anxiety and depression.
This may be particularly important since the genes involved play a major role in forming the brain connections needed for learning about fears. While all children have fears and anxieties, the authors suggest that children with low levels of activity of these genes develop anxious dispositions because they fail to learn to cope by overcoming their early childhood fears.
“Working with my close collaborator and graduate student, Drew Fox, we focused on understanding the function of genes that promote learning and plasticity in the amygdala,” says Dr. Ned H. Kalin, chair of psychiatry at the University of Wisconsin School of Medicine and Public Health, who led the research. “We found reduced activity in key genes that could impair the ability to sculpt the brain, resulting in a failure to develop the capacity to discriminate between real and imaginary fears.”
Kalin says the study helps support the need for early intervention in children identified as excessively shy and anxious. It may also point a way to better treatments aimed at decreasing the likelihood of children developing more severe psychiatric problems. Anxiety in children is quite common and can lead to anxiety and depression in adolescence and often precedes anxiety disorders, depression and substance abuse in adults.
Most small children go through a phase when they’re frightened of many things, including monsters or new social situations, Kalin says, but their maturing brains soon learn to distinguish real threats from the imaginary. But some children do not adapt, generalize their fears to numerous situations, and may later develop serious anxiety and mood disorders. These children tend to be more sensitive to stress, produce more stress hormones and have heightened nervous-system activity.
Kalin, Fox and co-authors wondered whether some differences in the developing amygdala prevent it from learning how to regulate and adapt to anxiety. Kalin’s earlier work identified a subset of young monkeys, similar to extremely shy children, with an inherited anxious disposition. Using brain imaging, the authors showed that high levels of amygdala activity predicted trait-like anxiety in anxious young primates. Like their stable and enduring anxious dispositions, these individuals also had chronically elevated levels of amygdala activity.
“We believe that this pinpoints a critical region in the brain that determines an individual’s level of trait anxiety,’’ Kalin explains.
In examining a specific part of the amygdala, the central nucleus, the researchers analyzed gene expression, which reflects both environmental and inherited influences. Within the central nucleus of the amygdala the authors found that anxious individuals tended to have decreased expression of a gene called neurotrophic tyrosine kinase, receptor, type 3 (NTRK3). Low levels of this gene that encodes for a brain cell surface receptor may be why the amygdala of an anxious monkey or child is chronically overactive and unable to overcome anxiety and fears.
“This is the first demonstration that the early risk to develop anxiety and depression may be related to the underactivity of particular genes in the developing primate amygdala,’’ Kalin says. “These findings have provided the basis for our hypothesis that can explain the early childhood risk to develop anxiety and depression. It also suggests some creative ways to help children with extreme anxiety by developing new treatments focused on increasing the activity of specific genes involved in facilitating the brain development that underlies fear learning and coping.”
(Source: newswise.com)
A Gene Implicated In Schizophrenia Risk Is Also Associated With Risk for Cannabis Dependence
A paper by Shizhong Han and colleagues in the current issue of Biological Psychiatry implicates a new gene in the risk for cannabis dependence. This gene, NRG1, codes for the ErbB4 receptor, a protein implicated in synaptic development and function.
The researchers set out to investigate susceptibility genes for cannabis dependence, as research has already shown that it has a strong genetic component.
To do this, they employed a multi-stage design using genetic data from African American and European American families. In the first stage, a linkage analysis, the strongest signal was identified in African Americans on chromosome 8p21. Then using a genome-wide association study dataset, they identified one genetic variant at NRG1 that showed consistent evidence for association in both African Americans and European Americans. Finally, they replicated the association of that same variant in an independent sample of African-Americans.
All together, the findings suggest that NRG1 may be a susceptibility gene for cannabis dependence.
An interesting feature of this paper is that these findings may also suggest a link between the genetics of schizophrenia and the genetics of cannabis dependence. NRG1 emerged into public awareness after a series of genetic studies implicated it in the heritable risk for schizophrenia. Subsequent studies in post-mortem brain tissue also suggested that the regulation of NRG1 was altered in the brains of individuals diagnosed with schizophrenia.
Thus, the current findings may help to explain the already established link between cannabis use and the risk for developing schizophrenia. A number of epidemiologic studies have attributed the association of cannabis use and schizophrenia to the effects of cannabis on the brain rather than a common genetic link between these two conditions.
"The current data provide a potentially important insight into the heritable risk for schizophrenia and raise the possibility that there are some common genetic contributions to these two disorders," commented Dr. John Krystal, Editor of Biological Psychiatry.
However, further research will be necessary to further confirm the role that NRG1 plays in cannabis dependence and the potential link between cannabis use and psychosis.
(Source: alphagalileo.org)
Worker honeybees shuttling between foraging and nursing tasks have been found to switch huge groups of genes on and off in their brains for each job. This shows for the first time that different behaviours can have specific gene patterns. The discovery could have implications for how our own behaviour influences which genes are switched on in our brains and bodies.
Researchers have identified five of the genes that shape a person’s face, work that could help scientists better understand facial abnormalities like cleft palate and someday might even help forensic investigators determine what a criminal suspect looks like from crime-scene DNA.
Researchers previously knew that genetics played a large role in determining face shape, since identical twins share DNA. However, little was known about exactly which genes are involved. Three genes were thought to have roles in the arrangement of facial features, and the new research confirmed their involvement. It also identified two other genes.
"We are marking the beginning of understanding the genetic basis of the human face," said lead researcher Manfred Kayser, head of the forensic molecular biology department at Erasmus MC-University Medical Center Rotterdam, Netherlands.
The study is part of the work of the International Visible Trait Genetics (VisiGen) Consortium, a group of six researchers who want to understand the genetics behind visible human characteristics.
Research shows gene defect’s role in autism-like behavior
August 10, 2012
Scientists affiliated with the UC Davis MIND Institute have discovered how a defective gene causes brain changes that lead to the atypical social behavior characteristic of autism. The research offers a potential target for drugs to treat the condition.
Earlier research already has shown that the gene is defective in children with autism, but its effect on neurons in the brain was not known. The new studies in mice show that abnormal action of just this one gene disrupted energy use in neurons. The harmful changes were coupled with antisocial and prolonged repetitive behavior — traits found in autism.
The research is published online today in the scientific journal PLoS ONE.
"A number of genes and environmental factors have been shown to be involved in autism, but this study points to a mechanism — how one gene defect may trigger this type of neurological behavior," said study senior author Cecilia Giulivi, professor of molecular biosciences in the UC Davis School of Veterinary Medicine and a researcher affiliated with the UC Davis MIND Institute.
"Once you understand the mechanism, that opens the way for developing drugs to treat the condition," she said.
The defective gene appears to disrupt neurons’ use of energy, Giulivi said, the critical process that relies on the cell’s molecular energy factories called mitochondria.
In the research, a gene called pten was tweaked in the mice so that neurons lacked the normal amount of pten’s protein. The scientists detected malfunctioning mitochondria in the mice as early as 4 to 6 weeks after birth.
By 20 to 29 weeks, DNA damage in the mitochondria and disruption of their function had increased dramatically. At this time the mice began to avoid contact with their litter mates and engage in repetitive grooming behavior. Mice without the single gene change exhibited neither the mitochondria malfunctions nor the behavioral problems.
The antisocial behavior was most pronounced in the mice at an age comparable in humans to the early teenage years, when schizophrenia and other behavioral disorders become most apparent, Giulivi said.
The research showed that, when defective, pten’s protein interacts with the protein of a second gene known as p53 to dampen energy production in neurons. This severe stress leads to a spike in harmful mitochondrial DNA changes and abnormal levels of energy production in the cerebellum and hippocampus — brain regions critical for social behavior and cognition.
Pten mutations previously have been linked to Alzheimer’s disease as well as a spectrum of autism disorders. The new research shows that when pten protein was insufficient, its interaction with p53 triggered deficiencies and defects in other proteins that also have been found in patients with learning disabilities including autism.
Source: UCDavis
Cancer May Result From Wrong Number of Genes
When a young person develops cancer, doctors most often assume that genetics are the reason, because the patient hasn’t lived long enough to accumulate environmental damage. But it’s been hard to find the faulty DNA behind many tumors. Now, using new genomic technology, scientists have discovered a novel explanation for some testicular cancers, the most common cause of cancer in men under 35. Rather than being triggered by a single gene mutation, the tumors are caused by too many or too few copies of a gene in a person’s cells. These “copy number variations” have been linked to other conditions such as autism, but never before to cancer.
Researchers map the expression patterns of 1,000 genes in the human brain.
The paper
H. Zeng et al., “Large-scale cellular-resolution gene profiling in human neocortex reveals species-specific molecular signatures,” Cell, 149:48-96, 2012.
The finding
Whole-genome sequencing has given researchers a good sense of which genes are shared between, for example, humans and mice. But little is known about how the expression patterns of these genes differ. Hongkui Zeng of the Allen Institute for Brain Science in Seattle, Washington, and colleagues took slices of human brains collected from postmortem biopsies and tested the expression of 1,000 key neuronal genes. They found that about 21 percent of the gene-expression profiles differed between the two species.
The sliver
Researchers took thin slices from regions of the brain involved in processing visual and sensory information and scanned them for the in situ expression of 1,000 genes that act as markers of cell type or are involved in disease, evolution, or cortical function. They compared gene expression of three areas of the cortex across 46 donors with corresponding mouse-brain slices, which had been analyzed previously at the Allen Institute.
The difference
The differences between humans and mice “often manifested in a cell type-specific way,” said Zeng, or involved in between-cell communications. “The disease genes are all very well conserved,” which bodes well for researchers using mice as models of disease, she says.
The impact
“The mouse model is used extensively in neuroscience research, and it’s assumed to be a surrogate for the human,” says Daniel Geschwind, a neurogeneticist at the University of California, Los Angeles. Knowing the specific differences “gives you a sense that many things are conserved, but also provides some guidance as to the ones that aren’t.”
New epilepsy gene identified; possible new treatment option
ScienceDaily (July 23, 2012) — New research conducted by neuroscientists from the Royal College of Surgeons in Ireland (RCSI) published in Nature Medicine has identified a new gene involved in epilepsy and could potentially provide a new treatment option for patients with epilepsy.
The research focussed on a new class of gene called a ‘microRNA’ which controls protein production inside cells. The research looked in detail at one particular microRNA called ‘microRNA-134’ and found that levels of microRNA-134 are much higher in the part of the brain that causes seizures in patients with epilepsy.
By using a new type of drug-like molecule called an antagomir which locks onto the ‘microRNA-134’ and removes it from the brain cell, the researchers found they could prevent epileptic seizures from occurring.
Professor David Henshall, Department of Physiology & Medical Physics, RCSI and senior author on the paper said ‘We have been looking to find what goes wrong inside brain cells to trigger epilepsy. Our research has discovered a completely new gene linked to epilepsy and it shows how we can target this gene using drug-like molecules to reduce the brain’s susceptibility to seizures and the frequency in which they occur.”
Dr Eva Jimenez-Mateos, Department of Physiology & Medical Physics, RCSI and first author on the paper said “Our research found that the antagomir drug protects the brain cells from toxic effects of prolonged seizures and the effects of the treatment can last up to one month.”
Epilepsy affects 37,000 in Ireland alone. For every two out of three people with epilepsy their seizures are controlled by medication, but one in three patients continues to have seizures despite being prescribed medication. This study could potentially offer new treatment methods for patients.
The research was supported by a grant from Science Foundation Ireland (SFI). Researchers in the Department of Physiology & Medical Physics and Molecular & Cellular Therapeutics, RCSI, clinicians at Beaumont Hospital and experts in brain structure from the Cajal Institute in Madrid were involved in the study.
Source: Science Daily