Philosophy of Genetics

The Sports Gene

We each receive a copy of the ACTN3 gene from our parents.  It's one of the 21,500 genes we all share.  Yet the ACTN3 gene comes in different variants, or flavors.  You may get the R variant from your father, and the X variant from your mother (RX), or some other combination like RR and XX..

Yet according to the New York Times, having the R variant of the ACTN3 gene enhances your so-called "fast-twitch" muscles, to make them more "capable of the forceful, quick contractions necessary in speed and power sports".  If you inherit the X variant, you won't have that same capability.

A study "looked at 429 elite white athletes, including 50 Olympians, and found that 50 percent of the 107 sprint athletes had two copies of the R variant. Even more telling, no female elite sprinter had two copies of the X variant. All male Olympians in power sports had at least one copy of the R variant."

Of course, to make it to the Olympics, you must train and practice.  But if you don't have the R variant of the ACTN3 gene, all the training in the world won't get you there. 

In reality, you need two sets of genes to become an Olympic athlete.  First, you must possess the "ACTN3 variant R" gene for "fast-twitch" muscles.  Then you also need the "brain genes" for the drive and motivation to sustain you through the long, arduous, thankless years of training.  Drive and motivation are also innate.

Men are Autistic, Women are Schizophrenic

Since the time of Descartes, scientists have struggled to carve a niche for themselves where they can work undisturbed by cultural, political, and religious wars.  For example, Descartes devised the so-called mind/brain distinction, whereby scientists agreed to limit their inquiries strictly to the physical world (e.g. the brain and body), and cede dominion of the "mind" and spiritual world to God and the all-powerful Church.

Today, two researchers, Bernard Crespi and Christopher Badcock, are attempting a similar segregation of turf.  Since it’s not politically correct to speak of a genetic basis for human behaviors (nor innate differences among people), they’ve reframed the discussion in terms of mental diseases, which are less threatening to cultural warriors.  Scientists are now free to explore the genetic basis of mental diseases, while they cede discussions of “normal” behavior to the current orthodoxy of cultural enforcers.

So what's their new theory?  According to the New York Times, Crespi and Badcock theorize that:

An evolutionary tug of war between genes from the father’s sperm and the mother’s egg can, in effect, tip brain development in one of two ways. A strong bias toward the father pushes a developing brain along the autistic spectrum, toward a fascination with objects, patterns, mechanical systems, at the expense of social development. A bias toward the mother moves the growing brain along what the researchers call the psychotic spectrum, toward hypersensitivity to mood, their own and others’. This, according to the theory, increases a child’s risk of developing schizophrenia later on, as well as mood problems like bipolar disorder and depression.

In short: autism and schizophrenia represent opposite ends of a spectrum that includes most, if not all, psychiatric and developmental brain disorders. The theory has no use for psychiatry’s many separate categories for disorders, and it would give genetic findings an entirely new dimension.

In other words, there’s a “psychotic spectrum” of genetically influenced human traits (from autism to schizophrenia), with us “normal people” somewhere in the middle.  At the outer reaches of the spectrum are mental diseases,  which scientists are free to study to determine their underlying genetic basis.  Within the broad middle of the spectrum, where genetic variation among humans presumably also leads to different personality traits, the implication will be left to cultural warriors (i.e the "Modern Inquisition") to explore.  (Why do some people have a “fascination with objects” and lack a “sensitivity to the moods of others”?  It must be the way they were raised, they'll say!)  Meanwhile, scientists will slowly work their way to the middle of the spectrum, and finally overcome the PC resistance with definitive proof of the genetic basis of human behavior, perhaps a few years down the road.

Gene Expression vs. Genetic Variation

Gene Expression measures which of your 20,500 genes are currently active in your body.   Genetic Variation describes the subtle differences between your 20,500 genes and your neighbor’s genes, which come in different flavors from your own.   (Both gene expression and genetic variation can be measured using "gene chips").

Measuring gene expression can be misleading, becomes sometimes the effect of a gene comes long after it is switched off.  Genes act as blueprints for miniature "protein factories" in our bodily cells.  That’s what gene expression is.  The resulting proteins ultimately build structures in the body, like organs and skin and muscles and brain tissue.  But once the structures are built, the genes involved can then switch off (or go into occasional “maintenance mode”).

For example, the genes responsible for the eye’s development can mostly switch off after we're born, so many of the “eye development” genes are no longer expressed in adults, although the development of the eye is clearly genetic.

If you’re genetically pre-disposed to macular degeneration (an eye condition), you probably have different flavors of the eye development genes from your neighbor (who doesn’t suffer from the condition).  That's gene variation.  Whether the eye condition is caused by variants of your “development genes” which long ceased their activity or by “maintenance genes” is an open question.  But if the former, you can treat the condition but never cure it.

So why aren’t all our genes dormant after we’ve reached adulthood?  Aside from maintenance genes (if you cut your finger, you’d better hope these are still active, to repair the skin!), why do some of our genes still actively express their proteins?

First of all, genes don’t just act as blueprints for bodily structure.  They build an elaborate signaling system in the body.  For example, during pregnancy, hormones are used to signal the need for bodily changes.  Hormones can also induce mood changes.  So the genes that produce hormones must be able to switch on when needed, to produce more “signal”. (Neurotransmitters are another type of signaling mechanism in the brain.)

Hormones and neurotransmitters would have no effect unless “receptors” were placed strategically around the body and brain, to detect their signal and trigger a response.  Hormone receptors are constructed and strategically positioned by the genes, although they are more permanent than the transient hormonal signal.  Like soldiers on a battlefield awaiting the general’s order or command, the release of hormones into the bloodstream act as a signal, to activate the battle plans of the trained and ready army.

  The brain has hormone receptors as well.  So special modules in the brain remain ready, listening and vigilant.  Once they detect the signal, they trigger a pre-established human behavior, e.g. maternal instinct.  Pre-established human behaviors are really "brain modules" built by the genes (when we were young) to enact certain specific behaviors.  Although those genes left behind brain modules that they constructed, are no longer active (i.e. no longer "expressed").

Much of your current gene expression is related to maintenance activities and fostering the body and brain’s elaborate signaling system.  But neither your development (body and brain) nor your signaling system works the same as your neighbor’s, because you have gene variants.  Your DNA differs from your neighbor’s by 1%, which doesn’t sound like a lot.  But two keys that are 1% different still open different locks.

Presidential Genetics

The New York Times wrote recently about "that gene that makes presidents want to be president". 

The article includes a quote from Ted Sorensen, the former counselor to President John F. Kennedy: “You have to not only have a sense of confidence but a pretty big ego — you have to almost be a fanatic.”  Other qualities mentioned include "ambition and drive" and "believing you have special gifts” and being attracted to the "elixir of adulation" and the "opportunity for immortality". 

Furthermore, “the nature of the relationship between leaders and the people around them is very important." 

So where do all these qualities come from?  What is it that makes a leader differ from a follower?  Why doesn't everyone have a pretty big ego and self-confidence and ambition and drive?  Why are those traits so rare?  Can we all exhibit those traits, and simply choose not to?  Why do most people feel comfortable as a follower?

Clearly, the brain is built by our genes.  We have an innate brain module that senses crowds.  Variations in our genes (from our neighbor's genes) cause us to react differently when this situation is detected.  Some feel stress, and some feel excitement.  You can't choose to have a big ego or not.  It's part of who you are.  You can't train someone to be motivated by power.

Depending on the gene variants (or flavors) you were born with, you choose (of seemingly free will!) to be one way or the other.  From conception, your gene variants act as blueprints for unique proteins that construct your brain in various configurations. (After the development and configuration of your brain, those genes are then switched off).  So once you're a few years old, your basic personality is established. 

It may take many years until you experience a crowd for the first time, and realize how it excites you (or not).  That's when leaders have their "aha!" moment. But most people are simply not born with "that gene [variant] that makes presidents want to be president".  That is why leaders are so rare.