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Entries in Genes (33)

Monday
Aug272012

Genes May Determine How We Vote

Comstock/iStockphoto/Thinsktock(NEW YORK) -- New evidence suggests that a handful of genes may be influencing election outcomes more than we think.

Genetic studies find that nature may be playing as significant a role as nurture when it comes to political traits. Certainly, learning and environmental factors play a role too in the development of political opinions, but new gene studies indicate that people may have natural tendencies when it comes to political ideology and partisanship, voting behavior and engaging in political violence.

In a review article published Monday in the journal Trends in Genetics, lead author Peter Hatemi, a professor in the political science, microbiology and biochemistry departments at Pennsylvania State University, said that making people aware of how their political behavior is shaped has implications for foreign policy, public health, attitude change, reducing discrimination and much else.

"We're seeing an awakening in the social sciences, and the wall that divided politics and genetics is really starting to fall apart," Hatemi said in a news release "This is a big advance, because the two fields could inform each other to answer some very complex questions about individual differences in political views."

It has long been assumed that environment and social influences had the biggest impact on a person's political preferences, but new research finds that genetics may play a larger role in political behavior than previously believed. For example, although adolescent experiences can influence political ideology, studies that looked at twins suggest how genetics comes into play. Comparisons between identical and fraternal twins found that once teenagers left home, only identical twins maintained similar viewpoints, while fraternal twins were more likely to hold divergent views.

This suggests that genetics – not just environment – may shape political ideology and partisanship.

Because the human genome is very complex, political traits are likely influenced by thousands of genetic markers. In other words, there is no specific gene tied to a specific political opinion.

It may be that certain genetic propensities may influence our emotions, which, in turn, influence political beliefs. For example, a tendency for high pathogen avoidance and phobias may manifest itself as xenophobia and ethnocentrism.

In particular, researchers have found specific genes that seem significant. Genes that have to do with dopamine and serotonin -- two chemicals in the brain known to influence emotion -- appear to have an effect on socialization, voter turnout and political participation. For example, researchers have already identified a gene on a dopamine receptor that causes people to have a large number of friends. Interestingly, these people tend to be more liberal.

However, experts caution that while genes certainly influence political behavior, it is not to say that there is a definite correlation.

"What you have to think of is more like genes encoding for height," said Nancy Cox, professor and section chief of genetic medicine at the University of Chicago. She emphasized that although there is some causality related to genes, many environmental factors also play a role, and "there is a very large number of genes whose variants help determine what a final adult height might be.

"Similarly, something as complex as political views may be influenced by genetics, but what you see is a cumulative effect of those very small genetic effects."

Identifying how genes are expressed in politics may influence public policy. For example, discussions about health care reform or social welfare may be related to fundamental beliefs about resource allocation.

"Making the public aware of how their mind works and affects their political behavior is critically important," Hatemi said. "This has real implications for the reduction of discrimination, foreign policy, public health, attitude change and many other political issues."

Copyright 2012 ABC News Radio

Thursday
Aug162012

Genes May Be Key to Long, Dementia-Free Life

Stockbyte/Thinkstock(NEW YORK) -- A study published online Wednesday in the journal Neurology shows some evidence that protection from dementia clusters in families.

Lead investigator Jeremy M. Silverman, a professor in the department of psychiatry at the Mount Sinai School of Medicine, and his colleagues examined 277 male veterans, aged 75 and older, who were free of dementia symptoms. They conducted blood tests to measure levels of a substance called C-reactive protein in the men's blood. Since high levels of C-reactive protein tend to correspond to high levels of dementia in younger elderly patients, some assume those elderly patients with high levels of C-reactive protein who do not develop dementia are somehow resistant to cognitive decline.

The researchers then interviewed 1,329 of the test subjects' relatives to assess their rates of dementia. What they found was that the rates of dementia in the families of patients who exhibited resistance was lower than the rate seen in families of patients who did not show resistance.

To validate these findings further, investigators repeated the study with an older group of 51 patients and surveyed 202 of their relatives. This group returned the same results. In both study populations, patients with resistance to dementia were over 30 percent less likely to have relatives with dementia.

Since C-reactive protein is not always linked to dementia, the conclusions drawn should be met with a critical eye.

"[Dementia] is a very complicated disorder, and the findings in a study like this need to be reproduced in other studies before they are going to be transformative," says Dr. Eric Larson, vice president for research at the Group Health Research Institute based in Seattle.

Still, while the study does not show exactly what is protective in these men, it offers some tantalizing possibilities for future investigation. Silverman's group is already examining the genes of other patients who seem to be protected from dementia and taking note of similarities.

"This study provides one more piece of evidence that 'the cure' may be staring at us from the faces of these survivors, if we could only make out specifically what it was," says Richard Coselli, professor of neurology at the Mayo Clinic in Scottsdale, Ariz. "It also gives us further reason to be optimistic that a cure is not impossible... nature seems to have already found a way."  

Copyright 2012 ABC News Radio

Wednesday
May022012

Pork and Genes: How Pork Smells Genetically Determined, Says Study

iStockphoto/Thinkstock(NEW YORK) -- If you find the smell of pork revolting, it could be because that's how you're genetically programmed to perceive it, according to a new study.

Scientists found that there's a gene responsible for how a compound in pork smells to humans. The gene determines whether pork smells like ammonia, urine and sweat, or if it smells more like vanilla. The compound, androstenone, is similar to testosterone and found in high concentrations in male pigs.

The researchers gave study subjects pork containing androstenone and separated them into two groups -- those who found the smell offensive and those who didn't. Genetic analysis of the subjects revealed that those who didn't like the smell had two copies of a specific form of a gene known as OR7D4. The others had only one copy of the gene.

But, it turns out, most people don't even notice the smell of androstenone.

"In North America and Europe, pigs are castrated, so the concentration of androstenone is quite low," said Hiroaki Matsunami, a co-author and associate professor of molecular genetics and microbiology at Duke University Medical Center. "The only time you find a high concentration of androsteone is when you eat wild boar meat."

That could soon change, however. The researchers noted that the European Union is considering a ban on castration because of concerns over animal welfare, and this debate has rekindled interest in how humans perceive the smell of pork and why two people may smell it differently.

"The data raise the possibility that more consumers will dislike male meat as a result of a castration ban," the authors wrote.

Androstenone is also found in other male animals, but it's found in particularly high amounts in swine, Matsunami said.

How food smells, as everyone knows, also affects how food tastes, and this research helps confirm just how much the nose knows when it comes to taste.

"When food is in your mouth, odors come from the back of the throat up to the nose," said Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia. "Taste is very complex. It depends on smell and other factors, such as personal experience and genetic background."

While the study is particularly interesting to scientists, it also demonstrates how genes play a role in many biological processes, including the senses.

"It's a very clear example of how people live in different sensory worlds, and some of the basis of that is our genetic differences," Beauchamp said.

Copyright 2012 ABC News Radio

Thursday
Apr262012

The Short Answer on Pygmy Height? Genes

Comstock/Thinkstock(PHILADELPHIA) -- Why do we walk on two legs instead of crawling around on all fours?  Why are sons so often taller than their fathers?  And why are pygmies so short?

It is human to ask these questions, and the answers can sometimes be found in the smallest places.

Researchers from the University of Pennsylvania announced on Thursday that they may have discovered why pygmies are short -- and the answer lies in the footprints of natural selection in the human genome.

Pygmy tribes are found all over the world and represent the largest group of mobile hunter-gatherers.  Pygmies are unusual in that their average height is a meager 4 feet, 11 inches.  They grow up just like other humans until they become teenagers, at which point they typically fail to undergo a normal growth spurt. Their short stature mirrors their short lifespan, with average life expectancy a mere 17 years.

These tribes have captured the interest of social scientists and biological researchers who, for years, have tried to understand why pygmies diverged from the norm. Theories on their short stature have ranged from suggestions that it was a natural adaption to their difficult lifestyle, to the notion that the thick forest kept them away from sunlight, decreasing vitamin D and leading to low calcium levels and slow bone growth.

More recently, it has been suggested that, due to their short life-span, the bodies of pygmies have evolved to shunt energy originally devoted to growth, in favor of efforts towards early reproduction.

But in the new study, published in the journal PLoS Genetics, researchers for the first time were able to apply new genetic tools to address this question -- and it looks like genes could hold the answer.

The researchers not only found genes linked to pygmy height, but they also found that those same genes are implicated in reproductive hormone activation and immune system function -- providing some explanation to how the trait has survived for 2,800 years.

“The truth is we don’t know where pygmies came from,” said lead researcher Dr. Sarah Tishkoff, associate professor of genetics and biology and the University of Pennsylvania.  “By looking at a million genetic variants across the genome, we finally have a good understanding of their ancestry.”

Tishkoff notes that pygmies’ genomes are a veritable toolbox that allows them to take on their challenging existence. They found that a gene associated with height was also linked to oxytocin, the hormone responsible for nipple stimulation and breast feeding in women, linking it to the theory of early reproduction and species preservation in such short-lived people.

Another gene, linked to bacterial resistance and immune function, also happened to shut down the actions of human growth hormone in the pygmies’ bodies.

“Everything is intricately linked,” Tishkoff said.  “As evolution is tinkering with one of these systems, others are affected as well.”

Tishkoff says she studies pygmy genes because she is interested in the science behind human adaption -- the what, when, where and why of human origins.

And while these findings certainly help us understand why a pygmy is shorter than the average Joe, they also show us how humans have adapted to their environments over time -- information that may help the rest of us adjust appropriately to our own futures.

Copyright 2012 ABC News Radio

Sunday
Apr082012

Discovery of More Than 600 Genes May Lead to Suitable Treatments for Stomach Cancer

Ryan McVay/Photodisc/Thinkstock(NEW YORK) -- Researchers have identified more than 600 new genes that are mutated in stomach cancer, and say that the findings may bring about treatments suited to the genetic make-up of stomach tumors, Health Day reports.

Less than 25 percent of stomach cancer patients survive more than five years after being diagnosed with the disease. The senior author of the study said that a lot is still unknown about the genetic abnormalities that cause stomach cancers, which could explain the poor treatment outcome. According to the World Health Organization, stomach cancer is the leading cause of cancer-related deaths worldwide and takes the lives of more than 700,000 people every year.

Researchers found that changing the functioning of the two genes that were identified modified the growth of stomach cancer cells. The study appears in the online April 8 issue of Nature Genetics.

Copyright 2012 ABC News Radio

Tuesday
Apr032012

PTSD, Depression Passed Through Generations, Study Finds

Jupiterimages/Thinkstock(LOS ANGELES) -- Researchers at UCLA have identified mutations within three genes, which according to them may make some people more likely to develop symptoms of post-traumatic stress disorder (PTSD) and depression.

The researchers analyzed 200 adults from 12 multigenerational families who were exposed to the 1988 earthquake in Spitak, Armenia, most of whom saw dead bodies lying in the streets and people who were severely injured.

The participants underwent psychological screening and a genetic test 14 years after experiencing the earthquake.  The researchers found that people with mutations in any of three genes responsible for secreting the happiness hormone serotonin had PTSD and depression symptoms.

Previous studies have suggested that PTSD is heritable among siblings who experience traumatic situations such as war.  But this study suggests that the disorder is also heritable through multiple generations, according to Julia Bailey, assistant professor in the department of epidemiology at UCLA, and co-author of the study.

“We found that both PTSD and depression are heritable and that they share genes,” said Bailey, who added that the findings are consistent with previous research suggesting a genetic connection between PTSD and depression.

Unlike previous studies, the participants in this study were not previously diagnosed with PTSD or depression, nor were they seeking any sort of treatment for their symptoms.

However, all of the participants were of the same ethnic background, so the findings may not apply to all people, the researchers wrote in their study published Tuesday in the Journal of Affective Disorders.

Copyright 2012 ABC News Radio

Thursday
Mar152012

Extreme Gene Testing: One Researcher’s Experience

Comstock/Thinkstock(STANFORD, Calif.) -- When you look at 56-year-old scientist Dr. Michael Snyder, it’s unlikely that “diabetes” would be the first word to come to mind.

“I don’t look like the type of man who has diabetes,” he said. “I have a thin frame and stay active.”

Based on his appearance, most other doctors would agree. However, Snyder’s first-of-its-kind research, through which he subjected himself to frequent lab tests over a period of more than a year, revealed that he did, in fact, have the condition -- and it allowed him to confront it earlier rather than later.

But it also afforded him a rare opportunity: to see the link between his genes and illness play out right before his eyes.

Snyder and colleagues at his lab at Stanford University have spent the past 14 months sequencing his genome -- frequently -- and following the changes in his health. He discovered his personal risk for developing type 2 diabetes, heart disease, a lethal blood disorder and skin cancer.  He saw his genome change in response to viral attacks on his body, including the development of diabetes after catching a respiratory virus from his children.

When Snyder noticed changes in his genome consistent with diabetes, he alerted his personal physician, who was skeptical at first. Laboratory testing, however, revealed an elevation in his blood sugar that lasted several months.

He changed his diet -- cut out sugary desserts, began exercising more frequently, and eventually lost 15 pounds. In his lab, these changes were evident in his genome, and on re-check at his doctor’s office, his diabetes was gone.

Snyder discovered other interesting ways to apply his personal genome monitoring to his own health. He figured out on his own the dosage he needed of his cholesterol-lowering medications based on his personal sequencing of liver proteins. He was able to draft a lineup of dosages for other medications, too, including the anti-diabetes medication he anticipated he needed.

It is easy to see how many in the general public might be interested in emulating Snyder’s approach. However, Dr. F. Sessions Cole from St. Louis Children’s Hospital warns that Dr. Snyder’s response to infection or development of type 2 diabetes may not be appropriate to apply to others -- at least not yet.

“Applicability to the general public will require larger studies to determine patterns,” he said.

For now, Snyder will continue to sequence his own genome regularly, following the hidden changes in real time.  He avoided developing complications from diabetes because of this monitoring. Before his study began, he saw his personal physician once every three years for a check-up.

“If I hadn’t seen the diabetes in my genome,” he said, “I wouldn’t have known it was there.”

Copyright 2012 ABC News Radio

Tuesday
Jan312012

Should People Know Their Genome Screening Results?

Comstock/Thinkstock(LONDON) -- If you were at a higher risk for developing a condition like Alzheimer's disease or breast cancer, would you want to know about it?

With rapid advances in genome sequencing, researchers are learning more about people's susceptibility to certain diseases. The advancement has uncovered a host of ethical questions concerning if people are entitled to information yielded by their genes.

In order to help answer this question, a British research institute introduced a new online survey to gauge people's opinions, asking questions such as whether relevant findings from genome studies should be shared with research participants and whether other information uncovered during analysis should also be shared.

A team of ethicists from the Wellcome Trust Sanger Institute developed the tool because of a disagreement with the current practice of keeping findings anonymous and not revealing information that could impact people's health later, according to a press release.

"Although the scientists might be trying to find the genetic basis of one disease, e.g. breast cancer, by virtue of looking across all genes in one go, they might uncover an increased risk of developing something else, e.g. Alzheimer's," an introduction to the survey says on the website. "The volunteer who provided their sample for genomic research might be interested in this information.  It hasn't been routine practice to share this, but should it be?"

"We need to understand what people want from whole genome testing," said Anna Middleton, an ethics researcher at the Sanger Institute.

Bioethicists in the U.S. say they would welcome public input.

"One of the implications of gathering this survey data is it will help determine what kind of policy ought to get made," said Art Caplan, professor of bioethics at the University of Pennsylvania, who was not involved in the Wellcome study. "We should be moving toward policy, but we have no idea what the public wants."

Caplan explained that there are a number of ethical challenges posed by genetic testing.

If scientists studying genes discover an increased risk for a condition that could affect other family members, should they be obligated to tell the research participant? What about that person's family members?

And, he said, who should deliver the news?  Should it be the research participant's doctor or the researchers themselves?

Copyright 2012 ABC News Radio

Friday
Jan272012

New Gene Test Could Spy Which Lung Cancer Will Recur

Hemera/Thinkstock(SAN FRANCISCO) -- In 2011, 220,000 Americans were diagnosed with lung cancer.  Eighty percent of those Americans had a form of the disease known as non-small cell lung cancer.

In its early stages, doctors usually decide to remove the tumor surgically.  But as Dr. Edward Kim, chief of head and neck medical oncology at MD Anderson Cancer Center in Houston, explained, what to do next is often a difficult question to answer.

"Patients with this early stage of lung cancer pose a real dilemma for clinicians," he said in an email to ABC News.  "The current literature is less than definitive when deciding between the benefit of the chemotherapy against the risk of chemotherapy side effects for the patient."

The reason the early stage of this kind of lung cancer is so tricky to treat is because about 50 percent of people with it will see it return after surgery.  That means that half of all patients with it might have been helped with chemotherapy, while the other half would have experienced no benefit from chemo, but considerable side effects and cost. So, for years, the question has been, "How can we tell these patients apart?"

Dr. David Jablons, chief of thoracic surgery at the University of California at San Francisco, believes he has found the answer.

In a study published in the journal Lancet on Thursday, Jablons, in collaboration with a large consortium in China, described a new genetic test to determine which of the surgically removed lung cancers will return.

"This is the largest molecular study done on lung cancer so far, and the results are really encouraging for lung cancer patients," Jablons says.

Developed by Pinpoint Genomics, the gene test was used to analyze lung cancer cells of more than 1,500 patients in the United States and China. Researchers examined 14 specific genes that are thought to make cancer more likely to return.  They then compared the results to see which patients actually had a recurrence and which patients did not.

Not only were they able to predict which patients had a return of their lung cancer, they found that this genetic test outperformed traditional methods used to predict the return of this cancer, opening the door to the possibility that the test will make it possible to decide who should get chemotherapy and who should not.

Copyright 2012 ABC News Radio

Tuesday
Dec272011

Schooling Boosts IQ, Study Suggests

Hemera/Thinkstock(OSLO, Norway) -- The more time you spend in school the smarter you get, according to a Norwegian study.

Researchers at the University of Oslo found that people who had more years of education under their belts had higher IQs. Scientists calculated a nearly four-point increase in IQ for every extra year of schooling -- suggesting that education, not just genetics, can have an impact on intelligence.

Researchers got their results by reviewing the records of men who had reached the age of 30 several years after their extra education, suggesting that the effect is long-lasting.

Copyright 2011 ABC News Radio







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