DNA Ain’t Destiny. No Kidding.

Double Helix bridge to Marina Bay Sands

Many in the genetico-literary science world have been gnashing their teeth over a recent New York Times story that remarks the unremarkable: a Study Says DNA’s Power to Predict Illness Is Limited>. (The article elaborates on a Science Translational Medicine paper, The Predictive Capacity of Personal Genome Sequencing.) Erika Check Hayden (a must-follow for good writing on genomics and genetics) rounded up the face-palming in the genomics and genetics community. My favorite quick check comes from Razib Khan:

Recall that height is ~90 percent heritable on the population level. But it turns out that the standard deviation of identical twin height differences is still ~35-40 percent that of random siblings! What I want to see next, an article in The New York Times: “Identical twins not always identical in height; genes don’t explain everything.”

That’s from a post in which Razib productively ponders why Kobe Bryant is a much better player than his father was. His point cannot, apparently, be made too many times: genes don’t just build us in a vaccum. They build us by responding, ever and always, to information incoming from the environment. It starts when sperm meets egg; it stops when you do. You’re not the product of a construction product. You’re the product of — you are — a constant conversation between your genes and the environment, which includes both you and the surrounding world.

Conveying that is very difficult work taken up by good geneticists and by good writers who write about genetics.

Which is one more reason to read Razib Khan, who has been standing watch on this for years, and Erika Check Hayden, who is just killing it these days. You can catch Razib at Gene Expression (where today you can catch him holding a baby. Find Erika at her byline at Nature, her posts at the incomparable group blog Last Word on Nothing, and her website. Twitter handles: RazibKhan and Erika_Check.

Changes: Corrected Science to Science Translational Medicine as source of the paper.

Image: Double Helix bridge to Marina Bay Sands, Singapore.

By usiruk, via Creative Commons license. Some rights reserved.

8 Comments

  1. Identical twins, from the moment their common zygote cleaves and separates to form them, from that very moment they are NEVER again identical. The reason for this is the phenomenon of Epigenetics.

    Presently science is just beginning to appreciate the importance of this. At it’s core, the interaction of biology’s quintessential elements: nucleic acids and proteins. The motive force behind this incredible process interacting with these elements: quantum physics! 

    Why do we physicians and scientist fumble so badly trying to employ all the resulting data from the genomics revolution? Simply put, present clinical medical practice completely ignores the importance of these two incredibly important sciences [Epigenetics and Biological Quantum Physics].

    Until modern medicine starts to truly integrate these concepts into it’s philosophical foundation, and until society understands the message Mr. Dobbs is trying to communicate in this post, don’t expect anything but confusion from “medical genetics”. As of this moment, I challenge the reader to find a doctor specializing in clinical epigenetics. I challenge the academic medical community to establish a real curriculum focused within this realm.

  2. I was actually thinking the other day that this is one of the most important concepts to get out to people right now…

  3. that is why we need good education to broaden our mind,we are not determined by genetic alone, otherwise, we would be reduced to biomaterial constructed from nucleic acid and protein in the same sense as hourse constructed from concrete and steel

  4. “you are — a constant conversation between your genes and the environment, which includes both you and the surrounding world”

    Yes, it can’t be said enough that genes do not  programmatically determine who we become. And, the way you put it is a big improvement over the old dichotomy of nature v nurture (which tended to imply that “I” am some inert substance formed by forces I don’t participate in)
    I’d like all reading this to consider replacing the word ‘conversation’  with ‘learning’… In every way not determined by nature, we are who we’ve learned to be – we become who we learn to become – “we” are learned. Not only do “I” learn, “I” am learned. This shift in perspective is vitally important.

    Learning is the central dynamic of being human.  And, because learning is implicate in everything not otherwise determined, like the tide that lifts all boats, changing how we relate to learning can change how we relate to everything. (See LEARNING at learningstewards )

  5. I’ve observed, and participated in, this nature vs nurture discussion for 40 years now- longer than many readers have been alive- and can say with certainty that scientific opinion has slowly, inexorably evolved to favor the primacy of the influence of genetics over that of the environment.  Back in the day the “blank slate” hypothesis was widely held- no serious scientist now believes that humans are canvasses on which the environment paints a portrait.  As humans we seem desperate to believe we have more control over our behavior and outcomes than we really do.  Otherwise, life can seem a bit pointless.  But in fact, no matter how hard we strive, the vast majority of us will never high jump 7 feet or figure out the dark energy/dark matter conundrum.  We simply don’t have the right equipment.

    In many cases, genes are definitely our destiny.  In a macro sense this fact is obvious- we are always born as humans and not as cats.  In a micro sense, single gene alterations can profoundly alter our health in many ways, or even kill us, no matter the environment (you can argue that the environment might have caused the nucleotide change to begin with, but that “dog chases tail” story can wait for another day.)  It’s almost certain that the catalog of life-defining sequences will expand dramatically as our genetic knowledge grows.  Remember, the field is still in its infancy. 

    And in fact we are definitely construction projects.  Two master builders, given exactly the same plans and materials, will not make identical houses.  Neither will 2 RNA/protein/enzyme systems.  In both cases mistakes are made, contingencies must be dealt with.  But what separates the master builder from the hack- and the reason most of us turn out reasonably well- is the shared ability to ignore, or at least smooth out, the majority of environmental oscillations and stick to the plan.  (So why anyone would expect “genetically identical” twins to be exact replicas is beyond me.  And let’s face it, for all the mostly subtle differences they may have, in most cases “genetically identical” twins are just stunningly, well, alike.)

    Of course the environment matters.  A malnourished kid will not develop normally.  Chemicals cause mutations.  A variety of activities may up-regulate or suppress certain genes.  Epigenetic influences are fascinating and undoubtedly important. Obviously genes and their kin don’t operate in a vacuum.  But all of this is secondary and, in the context of our overall development, occurs at the margin.  Too much of this discussion ignores the forest for the trees- otherwise, tonight, you’d be barking at the moon!

Leave a Comment

Your email address will not be published. Required fields are marked *