Ever considered taking a peek inside your genes?
Today it seems easy. First, sign up with a personal genetics company like AncestryDNA, 23andMe, or any of the more than a dozen American companies that currently offer the service. Then the procedure is pretty standard: Spit in a plastic tube, pop it in the mail, and wait for your results.
But how much can the average person learn from one of these tests? Can you really find out if you'll develop a disease like breast cancer or whether you'll pass that disease onto your kids?
To find out, we chatted with Robert Klitzman, a bioethicist and psychiatry professor at Columbia University and the author of the recent book "Am I My Genes?" And we learned that genes are, not surprisingly, complicated.
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In most cases, they can't tell you whether you or your children will develop a specific disease — even breast cancer.
Saying you have the gene "for" an illness typically means that one or both copies of a gene — you have two copies of each gene, one from each parent — has a mutation that's been linked with that illness. But having a mutated gene does not necessarily mean you'll develop that illness.
In 2013, Angelina Jolie wrote a column in The New York Times about her decision to have her breasts removed after she discovered she had a genetic mutation that dramatically raised her risk of developing breast cancer. She also had a family history of breast cancer.
About 10% of all breast cancers in the US are linked to the mutation Jolie had. About 90% of all breast cancers are not.
In other words, having the mutation doesn't necessarily mean you'll get breast cancer, but it does mean you're significantly more likely to get it — especially if you also have a family history of it. And not having the mutation doesn't mean you're risk-free. In other words, "you could have the mutation and not get it, or you could not have the mutation and get it," Klitzman said.
For psychological illnesses like depression or anxiety, the picture is even blurrier.
Many of our observable traits — from aspects of our personalities to the color of our eyes — cannot be narrowed down to one or two genes. This appears to be especially true for psychiatric characteristics like intelligence or illnesses like depression, said Klitzman. A 2014 study he co-authored published in the Journal of Genetic Counseling came to similar conclusions.
"For things like intelligence there's easily 100 different genes involved. So the notion that you're going to test for a few of them and that's going to be predictive, that's not reflecting the complexity of genetics and of the mind and brain," Klitzman said.
A 2015 study published in the journal Nature Neuroscience was the first to identify two networks — each of which contain hundreds of genes — that appear to play a role in cognitive function.
In order for one of these tests to really predict your risk of disease, it would have to account for two major factors: your environment and your behavior.
Genetics play a big role in whether we develop certain diseases, but so do our environment and behavior. Everything from what we eat to where we're raised and how often we exercise can affect our risk of developing certain diseases.
"Research suggests that some 50% of all depression cases are linked with genetics," Klitzman said. "The other 50% is environment. So if you're just looking at the genetic factors, you're missing everything else."
Smoking, for example, dramatically raises your risk of developing lung cancer and heart disease; eating right can help lower your chances of developing stomach cancer and of obesity.
See the rest of the story at Business Insider