Expert: Dana Krempels, Ph.D. - 12/6/2009

Question
QUESTION: Hello Dr. Krempels.

As a typical person with a rounded notion of what genes imply, there is one aspect of their role in human behavior which puzzles me.

You know, of course, of the old philosophical work-horse, "If you could go back in time and kill Hitler, would you do it?" Well, in the spirit of "There's not only A and B, but there is always C," I was wondering also what role the Butterfly Effect has to play here.

Now, I know full well how environmental effects play a major role in human development, but--all things there being equal, and rather than "killing Hitler," suppose here, one could magically go back in time to the moment of Hitler's conception and say, "NO! Any other sperm except THAT one!"

In short (and with social and environmental considerations unaltered), would any other sperm from the same father have produced the same tyrant--or is the future of a human being also predicated upon which one among millions of rival sperm achieves conception?

regards,
Dan

ANSWER: Dear Dan,

The short answer is:  Yes, it's surely possible that a different sperm would have resulted in a completely different person.  But no one can really be sure *how* different.  That's the mystery of "Nature vs. Nurture" that we're still wrestling to solve.

Not even identical twins (who are genetically identical) have the same personalities, and sometimes they are *very* different.  And there are people who are completely unrelated in terms of genetics, who share the same values and ideals--even if they had completely different upbringing.

We don't really know exactly why we are who we are, and there's always the possibility of that "butterfly effect" that you mention.

This is the type of question that must remain hypothetical, since it's impossible to subject to rigorous testing.  But it's very interesting, even if we will never know the answer for certain.

Hope that helps.

Dana



---------- FOLLOW-UP ----------

QUESTION: Hello again,Dr. Krempels.

I hadn't intended a follow-up question, but your thoughtful and considered answer prompted it in me.

We agree, that:
1) environmental factors, being external impetuses, these (and for the want of a better word) "pervert" the work of the gene.

2) Left entirely to its own devices—i.e., theoretically devoid of external influences—two different sperm of the same father (and in the same impregnation) CAN produce slightly different outcomes in a newborn. (So I don't have to murder Hitler; I merely have to give the offending sperm a Nytol!)

And so, my follow-up question.

In your opinion (and given you accept the theory of their existence)do you believe epigenes are the likely cause for any divergence?

regards,
Dan

(Ah, Life! Ain' it wunnaful!)  

Answer
Dear Dan,

Epigenetics is a hot topic in evolutionary genetics now, and there's almost nothing immune to its charm.  :)

Yes, I absolutely accept that the re-packaging of germline DNA between generations can be heritable *and* can change an organism's phenotype. But I think it's too early to say whether epigenetics played any role in the molding of the Homo sapiens that became Adolf Hitler.  It's possible.  But because we are not even *close* to understanding which human behavioral traits are governed by Nature or Nurture, and because epigenetics is a little bit of both, it will be a while before we can really address this question.

Hope that helps, sorta.  (And yes!  Life ai wunnaful!)

Dana