There’s a new dating service around, and it smells rather strongly of woo-woo

Firstly, how creepy is the company logo? Secondly, this interview shows that they’ve actually been around since last year, so it’s not new-new. Thirdly, let’s give this chap Eric Holzle credit for at least renovating the old idea of computerised dating with an actual physiological test on top of the clichéd questionnaire. CSI and its ilk has done a very good job of convincing the world that DNA tells scientists more than it really does, and does so with great rapidity and perfect accuracy, so the idea that a matching service can use DNA analysis to find a match will surely appeal to lots of people: “DNA-dating” sounds pretty cool.

I even remember learning about this as part of my own physiology education:

MHC proteins sit on the surface of cells and detect pathogens, but they also appear to play a role in sexual attraction. In sniff tests of dirty t-shirts, people tend to be most attracted to the scent of the shirt whose owner has different MHC alleles from the sniffer. One explanation is that this phenomenon evolved to promote genetic diversity between mates¹.

I can see why Holzle thought that this could make the basis for a business, but how to make it sound less, well, eugenic than simply using the test results to decide against certain potential mates on the basis of too much genetic similarity? Because everything I’ve read focuses on how this promotes more hybrid diversity and extends the breeding gene pool, which is very much a eugenical emphasis, and eugenics has become a nasty word (remember, it originally meant choosing breeding partners according to objective criteria, not the forced culling of “undesirables” with which it is now most associated). So, how to make it sound less clinically detached even though it involves labs and test tubes? Easy, Holzle focuses on other alleged benefits of testing MHC alleles on HLA genes (genes which are only speculated to influence human body odour anyway):

EH: With the more research I’ve done, the more benefits I’ve found to matching HLA gene. They go well beyond matching odor and scent.

KG: What are some of those additional benefits?

EH: I list 6 on my website, the first is natural body odor. Number 2 is a more satisfying sex life. Number 3, if you’re a woman and matched up with a proper HLA partner, you have a higher rate of orgasms. That came out in a University of New Mexico report in 2006. It’s interesting because it leads into another benefit, which is there’s less cheating when people are properly matched up.

These are pretty huge claims. Do they stack up?

Firstly, the idea that the bigger the difference, the greater the allure: is that really how it works, or is there a certain degree of variance between the histocompatibility alleles beyond which greater variance makes no more difference?

Secondly, is simple olfactory allure the best metric for measuring the likely success of a relationship? How many of us have been totally infatuated with a hottie who ends up as a relationship disaster area? Would histocompatibility be enough on its own to overcome someone eventually revealing themselves to be a total twerp? To be fair, the site itself acknowledges that these things matter:

We look at your personal values to help you find a soul mate. And our in-depth background checks provide one of the safest—and most honest—places for your search.

So, more about those 6 alleged additional benefits of a chemically tested partner?

1. You’ll love their natural body fragrance–they’ll smell “sexier” than other people.
2. You’ll have a more satisfying sex life.
3. If you’re a woman, you’ll have a higher rate of orgasms.
4. There will be less cheating in your exclusive relationship.
5. As a couple, you’ll be more fertile.
6. Your children will be healthier.

Horzle also has an in-depth explanation of the purported benefits of sexual interaction and reproduction with a partner possessing a variant MHC (Major Histocompatibility Complex) genetic profile (which they confusingly describe as “DNA matching”, when in fact it’s discarding any potential matches). At first read, it sounds good, but this leapt out at me, with respect to claim number 6:

To understand why, it’s important to know that our MHC genes are largely co-dominant—that is, the traits they express are defined equally by our mother and father. That’s different, of course, from some other traits, such as eye color, which is typically defined by one parent or the other. But our immune systems are defined equally by each parent.

Eye colour is typically determined by one parent? On what planet? Tell that to the couple who both have brown eyes who end up with a blue-eyed child because they both had a blue-eyed grandparent. This is basic Mendelian inheritance stuff. Sure, eye colour inheritance is inherited via an autosomal dominance pattern rather than a co-dominance pattern, which means that one phenotype will typically overrule the other, but the phenotype that a child displays is still determined by genetic contributions from both parents, and the genetic contribution from both parents is what would show up on any chemical tests on that particular area of our DNA. Both parents are still contributing to the mix, and is a co-dominant phenotypical expression objectively any superior to the various autosomal dominant phenotypical expressions? We know some autosomal recessive inherited phenotypical traits (e.g. haemophilia) are strongly disadvantageous, but are all of them?

I’ll be interested to see what leaps out as dodgy joining of the scientific dots to other folks.

So, really? They’re just another dating service doing all the same things with an added gimmick dressed up in a lab-coat. They have all sorts of caveats about how and why the DNA-dating won’t work for certain classes of people (on the pill? too bad for you!) and these pages address one of the key interpretations of the original studies regarding this that was the first thing that jumped into my brain: what the original studies actually showed is that people prefer the scent of folks with scents most different from those of their siblings, not those with scents most different from their own (we don’t notice our own scent, after all), and this seems to be an acquired trait from our nurture, not an inherited trait from our nature. If someone has been raised in a family that is not genetically related to them, they will react positively to scents that are unlike the parents and siblings with whom they grew up, but not react negatively to the scent of their actual blood siblings, which is how all those dramas where siblings separated at birth end up falling in love with each other as adults are, surprisingly enough, fully based on credible science.

TamaLeaver has concerns about the possibilities of breakdowns in the agency’s procedures regarding genetic privacy.

Notes:

1. “One explanation is that this phenomenon evolved to promote genetic diversity between mates.”
Biological traits don’t evolve to do anything i.e. there is no guiding purpose pushing evolution in any particular way, that’s just lazy journalistic shorthand for a much more random pattern of evolution. The inheritance of traits varies through normal recombination of DNA during reproduction, occasional errors in that recombination produce new traits, and rarer mutations do so as well, and any randomly emerging traits that simply happen to prove reproductively advantageous get passed on to descendants and may eventually become fixed in the population. Most variant traits are reproductively neutral, some are reproductively negative and a few are reproductively positive. Evolution drifts, it doesn’t march.

Via Ponderance & Lauredhel.