A scan of all the mutations in the human gene map shows something surprising – people of European descent are evolving fast, and not for the better.

The study finds that in the past 5,000 years, European-Americans have developed a huge batch of potentially harmful genetic mutations – many more than African-Americans.

The study, published in the journal Nature, may help explain why so many people develop diseases even though they don’t have common genetic mutations. It can also help explain why different people have so many different reactions to the same drug, said Joshua Akey of the University of Washington in Seattle who led the study.

It likely has to do with population explosion, Akey said. European populations expanded after the Ice Age ended and prosperous agricultural societies emerged. “The number of mutations that exist is directly attributable to the population growth that happened in the last 5,000 years,” Akey told NBC News.

“The things that allowed us to go from millions to billions of has also been the same process that has been pumping in all these new mutations.”

Akey and colleagues at genetics institutions across the country examined the gene sequences of more than 6,500 people – more than 4,200 European-Americans and 2,200 African-Americans. They were looking for small changes in the genetic code called single nucleotide variants – one-letter differences in the genetic code of A,C, T and G.

They found “an enormous excess of rare variants” in the European-Americans. And 73 percent of these mutations only appeared in the human genome in the past 5,000 to 10,000 years. Most were mutations that are known to weaken proteins, Akey said, and most of these harmful mutations were also in the people of European descent.

Now researchers are working to see which of these mutations might be associated with diseases. But many are in known disease-causing genes, such as the LAMC1 gene associated with premature ovarian failure, LRP1, which is linked with both Alzheimer’s disease and obesity and the CPE gene linked to hardening of the arteries.

Most are rare mutations – meaning they only affect a few people. “Some genes might be more disease-causing than other genes,” Akey said.

It may explain why it’s been so hard to find clear genetic links to many diseases. “We have been looking for disease risk where it isn’t,’ he said. “The last five to 10 years have been dominated by looking for common genetic variations that dominate common diseases. There is a lot of disease risk that is unexplained. Maybe there are classes of mutations that haven’t been looked at.”

The findings could explain why some people can smoke for a lifetime and never get lung cancer or heart disease, while someone else might suffer a heart attack despite having healthy blood pressure and cholesterol levels.

It definitely shows evolution in action, Akey said. “It’s just the process of evolution playing out in real time,” he said. “The dramatic population expansions that occurred over the past couple thousand years had a profound consequence on our genetic variability.”

Genetic mutations usually occur by accident – they are just mistakes that get made when DNA gets copied. They become important to evolution when they affect a person’s ability to survive and have children. The expansion of civilization, and the ability of societies to care for people who are less fit, was probably a factor in allowing these mutations to spring up, Akey said. “I think that is undoubtedly true,” he said.

Some of the genes identified in the scan also affect peoples’ response to drugs. That could explain why some people are helped, for example, by a cholesterol-lowering drug while others may not be. There wouldn’t have been much “selective pressure” on these genes before the modern drug era, but that doesn’t mean the genes were not influenced by something else. “It turns out that genes involved in adverse drug responses also have different biological roles,” Akey said – for instance, detoxifying certain foods.

There may even be more evolution in the future, Akey predicted. One example – phenylketonuria or PKU. It’s caused by a mutation in a gene that breaks down an amino acid called phenylalanine. People with PKU mutations must eat a strict, low-protein diet or they can develop seizures and mental retardation.

Now newborns are routinely tested for PKU so they can start the diet immediately and avoid any brain damage. Akey said because these kids can now grow up and lead normal lives, they will likely start having children and the gene may become more common in the population.

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A new study in the prestigious scientific journal Nature has shown a link between the risk of having a child with autism or schizophrenia and the age of the father.  The older the dad, the greater the risk that changes in the genes of his sperm will produce the behavioral disorder.

The older a man gets, the greater the chance for random changes or mutations in his sperm. A similar problem was well understood for women, who at age 35 and older are more likely to have a child with Down syndrome or other hereditary disorders.

It’s long been known that autism is in part a genetic disease. This newest study adding to that evidence is important, somewhat frustrating and heartbreaking.

Unfortunately, this study is unlikely to convince the noisy and influential few who would still link vaccines with autism.

There have been far too many Congressional hearings inspired by fringe science that have ended in pressure on the National Institutes of Health and the Centers for Disease Control and Prevention to study vaccines as the culprit behind autism.

 How many celebrities have gone on TV or led demonstrations demanding money for more studies of the alleged vaccine-autism link even though the Institute of Medicine, part of the National Academy of Sciences, has twice dismissed any connection to vaccination.  Why has it taken so long to discover the link to older dads and their genes as one possible contributor to rising autism rates? Jenny McCarthy, Jim Carrey, Rob Schneider, Donald Trump turn out to be about as reliable guides to medical facts as Missouri Rep. Todd Akin and his distortions about how women’s bodies respond to rape.

The discovery of the role paternal age plays is frustrating because there are too many factors leading to decisions to delay having children.  Women get the frequent message in the media that they can have children whenever they want— that technology makes parenting possible at any age.  Young men and women find too little support from government or business for child-rearing. 

The study is heartbreaking because it does not bode well for finding a cure for those already impacting by autism, schizophrenia and other age-related genetic disorders.  The impact of genetic mutations is huge and it is systemic. These genes are going to interact with the environment is complex ways that are not likely to be easily reversed by a drug or any other quick fix.

It’s not news that sperm can carry genetic mutations with serious consequences. Just last month a study showed little changes in the DNA of sperm can make men more likely to be infertile. Other studies have linked age-related sperm mutations to diseases such as Apert syndrome, a rare disease that causes webbed fingers and deformities of the skull, and achondoplasia, which is a type of dwarfism.

So we now know that the biological clock ticks for both sexes when it comes to the health of children.  And we now know that letting non-experts drive funding for biomedicine can lead to delays in getting the right answers to frightening epidemics such as autism.  And we now know that prevention is something we need to think about when it comes to what we tell young people when they think about having kids.  We now know a lot.  Let’s see if our leaders can put that knowledge to use in the future.

Art Caplan, Ph.D., is the head of the division of medical ethics at the NYU Langone Medical Center

Related links:

Older fathers more likely to have kids with autism. schizophrenia

Mutant sperm linked to infertility

Institute of Medicine report on vaccines and autism

Susan E. Matthews
MyHealthNewsDaily

How the body responds to opiates — the powerful, pain-relieving drugs that carry a high potential for addiction — may be partly determined by genetics, according to a new study.

Researchers studied 121 pairs of twins to look at the role of genetics in people's reactions to the pain medications. They found that genetic predisposition accounted for 59 percent of the variation between people's levels of nausea, 36 percent of the differences in how much people disliked the drug and 38 percent of the variation in itchiness in reaction to the drug.

The findings are important because the degree to which people experience unpleasant side effects, and like or dislike the drugs, can be a sign of how effectively the drugs treat their pain, and their potential to develop addiction, the researchers said. Liking a drug increases the susceptibility to addiction, while experiencing negative side effects decreases it.

“Genetics matter … people are different, and if we understand why they are different, we can take better care of them,” said study author Dr. Martin Angst, professor of anesthesia at the Stanford University Medical Center.

It's well-known that the pain relievers cause extremely different reactions in people, but the new study gives researchers a better understanding of how genetics could play a role in those reactions.

"Patients vary dramatically in how much pain relief they get, what extent they suffer from opiates and how much pleasure they get from opiates,” Angst said.

Opiates: reactions and addictions
Nearly 2 million people in the U.S. are addicted to prescription painkillers, a 2009 government survey found, and the problem is growing. Painkiller addiction often begins with a patient taking legitimate prescriptions.

Researchers believe the addiction problem could be curbed if people's reactions to the drugs were better understood, or could be predicted. Some patients may require 10 times the typical dose for adequate pain relief; others prefer lower doses that cause less extreme side effects, even though it means experiencing more pain.

In the study, participants were randomly assigned to receive either a small amount of a short-acting opiate or a placebo, followed by a heat probe or ice-cold water. Researchers spent 6 hours with each participant, but didn't know which treatment they'd received. General tolerance to pain was also assessed by applying the heat probe or cold water without any medication.

The study demonstrated that one of the most uncomfortable side effects, nausea, is strongly inherited, as genes account for almost two-thirds of variability between people.

The more severe side effects that come with opiates include slow breathing, which can result in death. Genetics accounted for 30 percent of the variation between people in respiratory depression, and 32 percent of dizziness, the study found.

Opiates represent a "double-edged sword — they’re really important drugs to relieve pain, but they come along with side effects," Angst said.

More personalized treatment
This line of research could result in a more personalized approach to administering the medications, the researchers said. Someday, people could be screened prior to use so doctors could understand their predispositions, and respond appropriately.

For example, screening could prevent a patient with a low tolerance for opiates from getting a high dose that could bring such euphoric feelings that they predispose the person to seek out the drug in the future, which could be the start of an addiction, said Dr. Doo-Sup Choi, who studies addiction at the Mayo Clinic.

Angst said further research must be done to determine which genes affect tolerance.

The study of 242 participants was large considering the amount of time spent with participants, and it was well-designed and well-performed, Choi said.

The study was published Wednesday in the journal Anesthesiology.

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By Robert Bazell,
Chief Science and Health Correspondent
NBC News

A readout of all of your DNA? You’ll get it soon. Many wealthy people have theirs already, but within years because of ever-accelerating technology it will be cheap enough for all, including every baby at birth.

So what will this “genetic blueprint” tell us of our future health?  Not much, according to an important study out Monday from a group of scientists at the Johns Hopkins University School of Medicine. They analyzed thousands of identical twins. Twins share the same genes from birth, so their experiences illustrate the insights to be gained from any individual knowing his or her genetic future.

The scientists looked at 24 common diseases and found that occasionally the complete genetic blueprint will alert people that they run a risk far higher than others for a certain disease. But most will get very little useful knowledge. The scientists presented their work at the annual meeting of the American Association for Cancer Research and published it simultaneously in the journal Science Translational Medicine

“Genomic tests will not be substitutes for current disease prevention strategies,” said Dr. Bert Vogelstein, one of the authors and a pioneer in the search for genes that increase cancer risk. 

So a blood test of the future will not free you from the need to eat healthy, exercise, keep extra weight off, not smoke and get useful cancer detection tests such as pap smears and colonoscopies. Nor will it relieve the ongoing possibility of nasty surprises about diseases you may have never feared.

But isn’t our genetic blueprint our destiny? Many scientists thoroughly believed that not long ago. As they have learned more about genes, however, that prediction appears ever more simplistic. 

Most diseases arise from a complex mixture of the genes we inherit from our parents at birth— not only what is measured in the whole gene test, but also our lifestyle and environment, and random events such as gene mutations occurring in individual cells in our body later in life.

One of the best examples of the dilemma of genetic testing comes from a test that has been on the market since 1996 for the cancer mutations called BRCA1 and BRCA2

If a woman is born with one of those mutations she has a 35 percent to 84 percent chance of developing breast cancer by age 70 and a 10 percent to 50 percent risk of getting ovarian cancer. Those odds are so high that women who test positive often elect to have their ovaries and/or breasts removed before cancer strikes. In those situations the test saves lives. But the problem is that fewer than one in 1,000 women carry those gene mutations.

And if women test negative for the gene mutations, the negative test does not at all mean she is in the clear. There are so many factors that increase risk for breast and ovarian cancer that a woman who tests negative for BRCA1 and BRCA2 only reverts to having the same lifetime risk as all other women – a 12 percent risk for breast cancer and 1.5 percent for ovarian cancer.

That set of complexities mirrors the situation for the thousands of other genes we carry that have some association with a disease.  If everyone has a complete gene profile, a small number can learn they have a great risk for something.  But for most, the information is minimally significant.

Not long ago many investors saw whole gene sequencing as a future gold mine. But these latest results show that the tests are unlikely to make many people wealthy -- or healthy.

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Daily serving of red meat raises risk of cancer, heart disease

Robert Bazell is NBC's chief science and medical correspondent. Follow him on Facebook and Twitter.

“People who are more empathetic seem to be better at affirming you,” Kogan says. “They are more understanding and they smile. They are going to have more open body posture; their arms are going to be out more, signaling ‘I’m here for you.’ Some, you are going to judge as more empathetic.”

Kogan and his team made this determination when they asked 116 University of Toronto students to watch a short, silent video clip of people with varying oxytocin receptors genes listening to their romantic partners tell them about a time of suffering. The ethnically diverse students -- average age 19 -- were asked to identify which people were more trustworthy, compassionate and cooperative.

After only 20 seconds, the people who watched the video could easily point out which listening partners had the double G genotype and were more empathetic because of their caring body language compared to people who did have this particular empathy gene.

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