Is love part of your DNA?

Happy Valentine’s Day!  On a day where people are overdosing on chocolate and champagne and whispering sweet nothings into each others ears, I want to tell some stories.  Three short stories (well, two stories and a research paper) that have to do with love.  And maybe not exactly love, but attraction, sex and genetic compatibility.

The Three Fs

When I was in graduate school, the research faculty at my institution (which, by the way is 125 years old and has created an awesome video about the laboratory here) focused on a lot of different scientific topics ranging from understanding cancer better to figuring out how the brain works.  Each Friday, we held “In House”, which was a seminar that the entire institution attended and one faculty member spoke about their recently published research.  My favorite line of all time from one of these seminars was a neuroscientist discussing the “The 3 F’s” that drive all life:  Feeding, Fleeing, and Mate Selection.

Ba dum tsssh…

No Genetic Disappointments

Photo Feb 14, 10 16 17 AMI think that every person on the planet has had their fair share of dating duds. I was no exception, however my Mom’s method for handling these less than ideal suitors was at times hysterical.  Typically, when people think about compatibility they consider whether one person is a night owl and the other person likes to wake up early or if they both enjoy the same hobbies.  However, my Mom decided to appeal to my scientific side and focus on genetic compatibility.  In particular, we discussed how we wouldn’t want my future children to end up with less than desirable personality or character traits through combining their “loser” genes with mine!  Well, scientifically, it doesn’t exactly work that way, but it was an entertaining topic of conversation.  So much so that when I met the author Tom Wolfe and had the opportunity to chat with him over coffee and dinner when he was researching “I am Charlotte Simmons“, I discussed my Mom’s argument in detail. When he inscribed my first edition of his “Bonfire of the Vanities” book, it charmingly said “To Cathy: with fond hopes there will be no genetic disappointments”

And you thought he should do his laundry

One of my favorite experiments (and well covered in the press) studied attraction using sweaty T-shirts.  The researchers had men wear a T-shirt for 2 days, and then women were asked to smell the sweaty T-shirts and decide which she found most attractive.  The interesting result, published in 1995, showed that women were more attracted to the scent of men who were more different from 6555 010them genetically.  The researchers determined this genetic diversity by looking at a set of genes call the Major Hisocompatibility Complex (or MHC, for short).  This is a family of genes that make proteins that mediate immune response.  There are 10 different MHC genes in humans, and each of these 10 MHC genes are slightly different genetically in different people.  These differences are what, for example, result in rejection in organ transplants or skin grafts.   These differences, however, are also what the researchers in the sweaty T-shirt experiment found attracted people to one another. The more different the MHC of the T-shirt wearer was from the T-shirt smeller, the more attractive the smeller found it.

Why did the researchers think that these “opposites attract”?  Honestly, they weren’t entirely sure.  One of the hypotheses was that it could be a way to increase diversity of these important immunity genes to improve our defenses against disease.  But does it really matter?  Because now your significant other will have a reason not to do the laundry – to be more sexy in the name of genetic diversity!

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