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DNA and Beer


Wednesday, October 16, 2013

“You sure love drinkin’ yer perfume,” I chide my boyfriend, as he orders a pint of Elephant Seal at our favorite local brewery, The Brewhouse. He loves bitter IPA beers. And black coffee. I love malty beers and mocha lattes. Now, instead of defending my finicky palate I have genetic research to back me up. It’s not me being persnickety. It’s in my genes.

How do I know this? Because we are living in the future! Here’s what I did: I spit into a cup, sent my spit to a company called 23andMe, and mere weeks later, I was perusing my genetic identity on a webpage. It cost me $200 (and the price has gone down since). There are several companies with similar services, such as Pathway Genomics, which is more medically based, or Family Tree DNA or Genebase, which focus more specifically on ancestry and start around $120. There are even sites that offer to identify the dog breeds in your pooch. We are now living in a reality like that in some futuristic sci-fi movie.

But back to the Brewhouse. I taste my boyfriend’s IPA and remark on its punch-you-in-the-face bitterness, and then I have an inspiration. I pull out my smartphone and hit the 23andMe app. I look at his and my genetic profiles under “bitter taste perception.” Sure enough, I, with a genotype of CG in a certain taste receptor gene, can taste PROP, a bitter molecule found in many foods. My boyfriend, with a genotype of CC, cannot. Validation!

The applications – and implications – for this technology extend far beyond me proving a point to my boyfriend. While I enjoy exploring mostly trivial genetic traits with the service, like the ability to detect asparagus pee smell, wet or dry earwax type, or hair curl, the site reports less trivial information, like lactose intolerance, fast-twitch muscle performance, and resistance to the nasty gastroentiritis-causing norovirus.

The site also contains information about genes that can have significantly more impact. Most traits, like height, are a result of many genetic and environmental factors and so the genes themselves will contribute a small amount to the overall trait, but there are some genes that just mean you won the genetic lottery (I’ve often wished I had hit the fast-twitch muscle jackpot). Conversely, there are some cases in which you genetically drew the short straw. For these, 23andMe inserts an extra step, a virtual sealed envelope, to ask, “Are you sure you want to see this?” before allowing users to view their results. Some examples are the familial version of Alzheimer’s or the high risk breast cancer BRCA genes. Which brings me to GINA.

In anticipation of the real possibility of the dystopian future of the movie Gattaca where “uteros” – those born without the assistance of genetic cherry picking – are subject to severe discrimination, congress has already enacted GINA, the Genetic Information Nondiscrimination Act. The Act prohibits health insurers from allowing an individual’s genetic makeup to influence their premiums. It also forbids employers’ use of genetic information to assist in hiring or firing decisions.

Personal genomic information has the potential to be abused or misinterpreted in some more subtle ways than outright discrimination. To illustrate: oxytocin is a hormone that correlates with “prosocial behavior.” For example, a new mother gets a rush of oxytocin when breast feeding, fostering bonding. Oxytocin is also correlated with trust, empathy, generosity, romantic attachment, and about a million other things in science literature. I like to think of oxytocin as warm fuzzies. It’s a hot topic, and recent research has identified a single variant in an oxytocin receptor (a receptor is a protein to which a signal molecule, like oxytocin, binds) gene that correlates with prosocial behavior.

What was the first thing I did when I heard this news on my favorite science podcast? That’s right. I went straight to my genetic profile and checked which flavor of the gene I had. And here’s where the knowledge is a problem: attributing something as complex as prosocial behavior to one gene is ridiculous.

This is one variation in an estimated 40 million in the human genome so far (for comparison, 23andMe has characterized under 1,000). Of those, many of them may contribute to personality traits. Moreover, personality traits, like “prosocial behavior,” are a very very complex result of genetics and environment. For example, if you were shunned as a child due to a physical deformity, you might be a little more wary of people despite possessing the “prosocial” version of the oxytocin receptor gene. This is the dangerous territory that makes overinterpretation of this information subject to the same fallacies as astrology.

Yet it’s irresistible. I have to admit, even as I rant about this oversimplification, I was relieved to find that both my boyfriend and I have the nice, warm fuzzies version of the gene. And I, as a trained scientist – I just completed my PhD in Biochemistry – should know better.

The real geneticists I spoke to, Ken Kosik and Bill Smith, both professors of molecular, cellular and developmental biology at UCSB, echoed this sentiment. “Many genes are not completely deterministic,” said Kosik. And, speaking a little more closely to what I’m wrestling with here, “There’s a tiny effect, the press gets a hold of it, and they blow it out of proportion,” said Smith.

While Kosik says, “We’ll get this all eventually,” there are limits in how much genetics determine all that makes up a human being, especially personality. And, to be honest, even if we could nail it all down, I guess I want for there to be some mystery. Don’t get me wrong. There’s no question about the value of understanding, for example, risk for disease based on one’s cholesterol metbolism; that is actionable information that can be ameliorated with diet or pharmaceuticals. But when it comes to fuzzier things like prosociality, motivation, kindness, intelligence, physical attractiveness, or creativity, I want there to be some unknown.

After all, maybe I am just picky when it comes to beer.

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