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Gene mutation helps explain night owl behavior

Night owls are often diagnosed at sleep clinics with delayed sleep phase disorder (DSPD). This study is the first to implicate a gene mutation in the development of DSPD, which affects up to 10% of the public, according to clinical studies. People with DSPD often struggle to fall asleep at night, and sometimes sleep comes so late that it fractures into a series of long naps. DSPD and other sleep disorders are associated with anxiety, depression, cardiovascular disease, and diabetes. People with DSPD also have trouble conforming to societal expectations and morning work schedules. "It's as if these people have perpetual jet lag, moving eastward every day," says Young. "In the morning, they're not ready for the next day to arrive." Patke is a night owl and usually works late into the night. She, however, does not carry the CRY1 variant. Not all cases of DSPD are attributable to this gene mutation. However, Young and Patke found it in 1 in 75 of individuals of non-Finnish, European ancestry in a gene database search. "Our variant has an effect on a large fraction of the population," she says. Young, who has studied the genes involved in the circadian clock of the fruit fly, connected with clinical researchers at the Weill Cornell Medical College to understand the molecular underpinnings of human sleep disorders. By studying the skin cells of people with DSPD, he and Patke discovered a mutation in CRY1, which helps drive the circadian clock. The circadian clock is a fundamental element of life on Earth and has remained more or less the same, genetically, throughout the evolution of animals. "It's basically the same clock from flies to humans," Young says. Normally the clock begins its cycle by building up proteins, call activators, in a cell. These activators produce their own inhibitors that, over time, cause the activators to lose their potency. When all the activators in the cell have been silenced, inhibitors are no longer produced and eventually degrade. Once they've all gone, the potency of the activators surges, and the cycle begins again. The CRY1 protein is one of the clock's inhibitors. The mutation Young and Patke found is a single-point mutation in the CRY1 gene, meaning just one letter in its genetic instructions is incorrect. Yet this change causes a chunk of the gene's resulting protein to be missing. That alteration causes the inhibitor to be overly active, prolonging the time that the activators are suppressed and stretching the daily cycle by half an hour or more. In addition to their initial study of a multigenerational family in the U.S., Young and Patke collaborated with clinical researchers at Bilkent University to analyze the sleep patterns of six families of Turkish individuals, 39 carriers of the CRY1 variant and 31 non-carriers. The carriers had delayed sleep onset times and some had fractured, irregular sleep patterns. The mid-point of sleep for non-carriers was about 4 a. m. But for carriers, the mid-point was shifted to 6-8 a.m. Because the mutation does not disable the protein, it can have an effect on individuals whether they carry one or two copies of the gene. Of the 39 Turkish carriers studied, 8 had inherited the mutation from both parents, and 31 had inherited only one copy of the mutation. The circadian clock responds to external environmental cues, so it is possible for people to manage the effects of the mutation on sleep. For instance, one carrier in the study reported maintaining a sleep routine through self-enforced regular sleep and wake times and exposure to bright light during the day. "An external cycle and good sleep hygiene can help force a slow-running clock to accommodate a 24-hour day," says Patke. "We just have to work harder at it."

Are your muscles genetically prepared to run a marathon? The way is open for the use of genetics in training -- ScienceDaily

Specialists focussed on seven genes related to muscle function in 71 experienced marathon runners, who underwent blood tests before and after the competition and measurements of the power of the vertical jump and muscle perception. Every gene was assigned a score, based on previous studies, where 0 indicated that the polymorphism of this gene did not create a muscular advantage for running a marathon, 1 meant a standard level and 2 indicated that the polymorphism of the gene conferred positive properties for bearing this effort through muscles. As such, runners with a high score -the maximum was 14 points- had good muscle genetics to bear the muscle demands of the marathon, while a low score indicated the opposite. The results were conclusive: runners with a higher genetic score had lower levels of creatine kinase and myoglobin in their blood, that is, less damage to muscle fibres, compared to marathon runners with a less favourable score. This research opens the way for the use of genetics in training. "In the near future, marathon runners may be able to measure their genetic profile to know how prepared they are for competing in a marathon and in other resistance tests," highlighted Del Coso.

Blue-eyed humans have a single, common ancestor -- ScienceDaily

"Originally, we all had brown eyes," said Professor Hans Eiberg from the Department of Cellular and Molecular Medicine. "But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a "switch," which literally "turned off" the ability to produce brown eyes." The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The "switch," which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris -- effectively "diluting" brown eyes to blue. The switch's effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour -- a condition known as albinism.

Practice Doesn’t Make Perfect - The New Yorker

In one study, for instance, Hambrick looked at pianists and measured their working memory, or the ability to keep chunks of information in mind and accessible for short periods of time. In the past, working-memory capacity has been found to be heritable. In his sample, it predicted success even when you accounted for the effects of practice; pianists with better working memory were better at sight reading—and increased practice did not alter the effect. When he looked back to one of the most frequently studied groups in expertise research, chess players, he found that, in addition to working or short-term memory, three more components of cognitive ability—fluid reasoning, comprehension knowledge, and processing speed, all abilities that are, to some extent, heritable—were related to performance. This was especially true of younger and less experienced players. If you’re naturally better, you don’t have to practice quite as much to get good.

35% of brain activity related to anxiety is heritable

An over-active network of brain areas is central to how children inherit anxiety and depression from their parents. The network consists of three regions in the brain which work together to control the fear-response. Genes passed down from parents to children influence how these three regions function together, the new study finds.

Research shows certain genes, in healthy environments, can lengthen lifespan -- ScienceDaily

The researchers found that the dopamine D2 receptor gene (D2R) significantly influences lifespan, body weight and locomotor activity, but only when combined with an enriched environment that included social interaction, sensory and cognitive stimulation and, most critically, exercise.

Scientists eliminate core symptom of schizophrenia in mice: Team uses chemical compound to restore affected brain regions; findings could lead to new treatment strategies -- ScienceDaily

"Schizophrenia affects about one in every 100 people, but for those with a 22q11.2 microdeletion, that chance jumps to one in three," said Dr. Gogos. "22q11.2 microdeletions remain the single greatest genetic risk factor for developing schizophrenia. This is why our model has proved invaluable in allowing us to trace schizophrenia back to its beginnings."

Study of Holocaust survivors finds trauma passed on to children's genes | Science | The Guardian

The team were specifically interested in one region of a gene associated with the regulation of stress hormones, which is known to be affected by trauma. “It makes sense to look at this gene,” said Yehuda. “If there’s a transmitted effect of trauma, it would be in a stress-related gene that shapes the way we cope with our environment.” They found epigenetic tags on the very same part of this gene in both the Holocaust survivors and their offspring, the same correlation was not found in any of the control group and their children.

Important associations between genetics, sleep behavior identified by study -- ScienceDaily

The focus of the CPMC paper was to identify the genes associated with sleep duration and validate the connection between sleep and several demographic and lifestyle factors, including age, gender, weight, ethnicity, exercise, smoking and alcohol. Analysis implicated genes involved in ATP metabolism, circadian rhythms, narcolepsy, sleep cycles in mice, and bear hibernation.

Changes in brain connectivity protect against developing bipolar disorder -- ScienceDaily

"The ability of the siblings to rewire their brain networks means they have adaptive neuroplasticity that may help them avoid the disease even though they still carry the genetic scar of bipolar disorder when they process emotional information," said Sophia Frangou, MD, PhD, Professor of Psychiatry at the Icahn School of Medicine at Mount Sinai and lead author of the study. Dr. Frangou's ongoing research uses neuroimaging to study how differences in brain wiring can either increase or decrease the likelihood of developing mental health problems.

Schizophrenia gene traced in chicken study -- ScienceDaily

"These results point to the same genes affecting anxiety in animals as diverse as chickens and humans. It also demonstrates that chickens may make an excellent model for the genetic basis of anxiety," says Dr. Wright.

Circadian rhythm of genes in brain changes with aging, research shows

A 24-hour circadian rhythm controls nearly all brain and body processes, such as the sleep/wake cycle, metabolism, alertness and cognition,[…]"Studies have reported that older adults tend to perform complex cognitive tasks better in the morning and get worse through the day," Dr. McClung said. "We know also that the circadian rhythm changes with aging, leading to awakening earlier in the morning, fewer hours of sleep and less robust body temperature rhythms."[…] Using the information they had about the time of death, they identified 235 core genes that make up the molecular clock in this part of the brain. "As we expected, younger people had that daily rhythm in all the classic 'clock' genes," Dr. McClung said. "But there was a loss of rhythm in many of these genes in older people, which might explain some of the alterations that occur in sleep, cognition and mood in later life."

Protein that boosts memory (and erases bad memories?) identified

In an earlier study, the Heidelberg scientists learned that there are reduced levels of Dnmt3a2 protein in the brains of older mice. When the elderly animals were injected with viruses that produce this protein, their memory capacity improved. "Now we have found that increasing the Dnmt3a2 level in the brains of younger mice also boosts their cognitive ability," explains Prof. Bading. In a number of different long-term memory tests, including classic Pavlovian conditioning, the scientists were able to demonstrate that mice with more Dnmt3a2 on board performed considerably better.

Does Exercise Slow the Aging Process? - The New York Times

Specifically, someone who participated in a single activity, earning them a 1, was about 3 percent less likely to have very short telomeres than someone who didn’t exercise at all. That risk declined more substantially if someone exercised more. People who reported two types of exercise were 24 percent less likely to have short telomeres; three types of exercise were 29 percent less likely; and those who had participated in all four types of activities were 59 percent less likely to have very short telomeres. Interestingly, these associations were strongest among people between the ages of 40 and 65, the researchers found, suggesting that middle age may be a key time to begin or maintain an exercise program if you wish to keep telomeres from shrinking

DRD4 gene, present in ~1/4 people, doubles alcohol consumption near heavy drinkers

When confederates quaffed multiple alcoholic drinks, carriers of the gene variant consumed an average of almost two wine or beer servings, versus almost one serving for noncarriers.

Are habits (or nurture) actually just epigenitics

Molecular analyses of the collected tissue samples showed that the regulation and activity of clock genes was altered after one night of sleep loss. The activity of genes is regulated by a mechanism called epigenetics. This involves chemical alterations to the DNA molecule such as methyl groups -- a process called methylation -- which regulates how the genes are switched on or off. The researchers found that clock genes had increased numbers of such DNA marks after sleep loss. They also found that the expression of the genes, which is indicative of how much of the genes' product is made, was altered. "As far as we know, we are the first to directly show that epigenetic changes can occur after sleep loss in humans, but also in these important tissues," says Dr. Cedernaes. "It was interesting that the methylation of these genes could be altered so quickly, and that it could occur for these metabolically important clock genes," he continues.

Cell aging slowed by putting brakes on noisy transcription

"We used budding yeast, a single-cell organism, to study the epigenetic regulation of aging and this simple model turned out to be quite powerful," explained Sen. In yeast, aging is measured by the number of times a mother cell divides to form daughters before it stops. This number - a mean of 25 divisions -- is under tight control and can be either reduced or increased by altering histone modifications, as the researchers found. They showed that when fewer chemical groups of a certain type attach to yeast histones, the abnormal transcription greatly increases in old cells. In contrast, the team found that in yeast strains with a certain enzyme deletion, this abnormal transcription is reduced and lifespan is extended by about 30 percent. "We have started investigating whether such a longevity pathway can also be demonstrated in mammalian cells", says Berger. "However, these investigations are confounded by the complexity of the genome in more advanced organisms. One of our long-term goals is to design drugs that can help retain these beneficial histone modifications and extend healthy lifespan in humans."

Scientists reverse aging in human cell lines and give theory of aging a new lease of life -- ScienceDaily

The Tsukuba team in particular has performed some compelling research that has led them to propose that age-associated mitochondrial defects are not controlled by the accumulation of mutations in the mitochondrial DNA but by another form of genetic regulation. The research, published this month in the journal Nature's Scientific Reports, looked at the function of the mitochondria in human fibroblast cell lines derived from young people (ranging in age from a fetus to a 12 year old) and elderly people (ranging in age from 80-97 years old). The researchers compared the mitochondrial respiration and the amount of DNA damage in the mitochondria of the two groups, expecting respiration to be reduced and DNA damage to be increased in the cells from the elderly group. While the elderly group had reduced respiration, in accordance with the current theory, there was, however, no difference in the amount of DNA damage between the elderly and young groups of cells. This led the researchers to propose that another form of genetic regulation, epigenetic regulation, may be responsible for the age-associated effects seen in the mitochondria.

How thick are Hungary's Asian roots?

A group of geneticists at the University of Szeged did research on the DNA composition of human remains from graves dating from the early tenth century. On the basis of their findings they came to the conclusion that the number of invaders was most likely very small because even in these early graves only 36% of the people had markers indicating Asiatic origin. Fifty percent of them were of purely European origin. Their DNA indicated that their ancestors had lived in Europe for at least 40,000-50,000 years. By now 84% of the Hungarian-speaking inhabitants of the Carpathian basin are of purely European origin, and only 16% carry any Asiatic markers at all.

Molecular Psychiatry - Genetics and intelligence differences: five special findings

It would be reasonable to assume that as we go through life, experiences—Shakespeare’s ‘whips and scorns of time’—have a cumulative effect on intelligence, perhaps overwhelming early genetic predispositions. However, for intelligence, heritability increases linearly, from (approximately) 20% in infancy to 40% in adolescence, and to 60% in adulthood. Some evidence suggests that heritability might increase to as much as 80% in later adulthood47 but then decline to about 60% after age 80.48
To a striking extent, your overall life chances can be predicted not just from your parents’ status but also from your great-great-great-grandparents’. The recent study suggests that 10 percent of variation in income can be predicted based on your parents’ earnings. In contrast, my colleagues and I estimate that 50 to 60 percent of variation in overall status is determined by your lineage. The fortunes of high-status families inexorably fall, and those of low-status families rise, toward the average — what social scientists call “regression to the mean” — but the process can take 10 to 15 generations (300 to 450 years), much longer than most social scientists have estimated in the past.
To a striking extent, your overall life chances can be predicted not just from your parents’ status but also from your great-great-great-grandparents’. The recent study suggests that 10 percent of variation in income can be predicted based on your parents’ earnings. In contrast, my colleagues and I estimate that 50 to 60 percent of variation in overall status is determined by your lineage. The fortunes of high-status families inexorably fall, and those of low-status families rise, toward the average — what social scientists call “regression to the mean” — but the process can take 10 to 15 generations (300 to 450 years), much longer than most social scientists have estimated in the past.