On gene duplication and oppression, a reprise.

On gene duplication and oppression, a reprise.

Evolution depends upon the unnecessary.

Evolution is a process in which those organisms best suited to their environments – either because they persist longer than others or produce more progeny – become more abundant.  For a lineage to become better suited to an environment over time, the organisms have to change in a heritable way.

DNA polymerases aren’t perfect.  Whenever enzymes copy our genetic material, they make mistakes.  To be honest, these mistakes are rarely beneficial.  Sometimes they cause other enzymes to stop working.  Sometimes they turn a cell into cancer.  But that same imperfection – which changes genetic information from one generation to the next – gives rise to evolution.

The evolution of a particular species of bacteria has been carefully documented in biologist Richard Lenski’s laboratory.  These were allowed to compete inside a precisely-controlled environment over hundreds of thousands of generations, and some of the bacteria were frozen after every few hundred generations to keep track of all the genetic changes.

Zachary_Blount_and_Richard_Lenski
Zachary Blount and Richard Lenski horsing around with some of the Petri dishes from Blount’s work on the evolution of citrate utilization in one . Image from Wikimedia.

In this experiment, a single subpopulation gained the ability to metabolize a new nutrient, which gave it a huge competitive advantage and allowed it to conquer its tiny world.  But how?  After all, most of a bacteria’s genes are already important for something, and, when mutations occur, the most common outcome is for functions to be lost.  If you give a radio and a screwdriver to a toddler, you probably shouldn’t expect crisper reception come evening.  Chances are that your radio won’t work at all.

256px-Gene-duplication.png
Gene duplication, as depicted by the National Human Genome Research Institute on Wikimedia Commons.

As it happens, a very rare event happened before this bacterial subpopulation “learned” to use the new energy source.  When the experiment was re-started with various frozen samples, most lineages never acquired this ability.  But in one set, there had been a “gene duplication event.”  During cell division, the enzyme that copies DNA had stuttered and accidentally included two copies of a gene that bacteria only need one copy of.  And these bacteria, recipients of that unnecessary second copy, would almost always gain the new metabolic function and swamp out the others.

Once there were two copies of the gene, the second copy was free to change.  A mutation in that copy wouldn’t cause the bacteria to grow weak or die, because they still had a fully-functional copy of the enzyme.  And eventually, through the rare happenstance of random error, bacteria would accumulate enough mutations in that second copy that it gained a new function.

In the beginning, this new function was pretty weak.  But once there was a faint glimmer, natural selection could refine it.  Without an unnecessary second copy of that gene, though, the bacteria never would’ve gained the new metabolic pathway.

You can look at human culture in a similar way.  Which isn’t to say that one culture is intrinsically better than another, and certainly doesn’t imply that we’re progressing toward some teleological goal.  Evolution is just a matter of statistics, after all.  The things that are, now, were probably descended from things that were good at being and producing.

A_textbook_on_mechanical_and_electrical_engineering_(1902)_(14585520259)
An image from a 1902 engineering textbook from Wikimedia Commons.

For instance, cars make human life easier.  And so the traits that allow a culture to have cars, like a basic understanding of mathematics and a willingness to follow rules on roadways, seem to spread pretty easily.  Car cultures have swamped out non-car cultures all over the planet.  Walking is pretty great, and so are bikes, but any culture that has access to mechanical engineering textbooks seems to have a pretty huge advantage over those that don’t.

But if you’d dropped a mechanical engineering textbook into the lap of a Paleolithic hunter-gatherer, it’d seem pretty useless.

It took a lot of waste to reach a state when the textbook could matter.  Over many generations, there was excess and dead weight.  Many centuries of an oppressor class stealing from the mouths of the poor, really.

Somebody who is struggling every day to procure food doesn’t have the luxury to fiddle with mathematics.  That’s why so many of the early European scientists were members of the aristocracy.  They didn’t need to work to eat because they had serfs to steal food from, levying taxes for the use of land that was “theirs” because their ancestors had done a bang-up job of murdering other people’s ancestors.

In the generations after humans developed agriculture, the average quality of life plummeted.  If you were told to pick any year and your soul would be suddenly re-incarnated (pre-incarnated?) into a randomly-chosen Homo sapiens alive at that time, you’d probably be happier 20,000 years ago than at most times during the last few millennia.  20,000 years ago, nobody lived terribly well – there was scant medicine and a constant risk of famine – but the suffering and servitude experienced by the majority of humans later on was worse.

After farming, people worked harder, for more hours a day, to produce a less varied, less healthful diet than the hunter-gatherers had eaten.  They had even less access to medicine, and still endured the constant risk of famine.  Oh, and envy.  Because farmers, who had to live in place, could be conquered.

640px-Maler_der_Grabkammer_des_Sennudem_001Those conquered farmers could be taxed, charged rent, etc., with the proceeds used to feed an idle class.  Most of the idlers produced nothing of value.  They ate others’ food and lived in un-earned luxury (although their “luxury” would seem pretty shabby to us).  But a few of them – a very few – produced the cultural innovations (like mathematics, medicine, poetry, astronomy) that gave us the modern world.

It feels more than a little disconcerting that a gruesome history of violence and oppression allows me to type this essay on a laptop computer.

In the past, though, oppression was the only way for our world to have “excess” people, those who could be free to devote their time and energy toward changing things.  Now, however, food production (and many other things) has been heavily automated.  We could have a much larger excess population, which could increase the rate of cultural evolution.  A luxurious lifestyle could be had by all using the essential (food- and shelter-producing) efforts of a smaller number of people than ever before.

With a guaranteed basic income – which could be funded by taxing wealth at a very low rate, maybe a percent or two – nearly all people could effectively become aristocracy.  People could follow their passions and curiosities.  Most, as ever, wouldn’t change the world. That’s how evolution works.  Chaotic tinkering with things that are pretty good rarely improves things.  But with billions of tinkerers, the odds that something works out are better.

It’s easily within reach.  Instead we’ve stuck with the same system of celebrating historical violence that was used to oppress people before.  Maybe it was necessary, all that cruelty, to get from our past to here.  But it certainly isn’t needed now.

Featured image: DNA duplication diagram by Madeline Price Ball on Wikipedia.

On scrutiny.

On scrutiny.

We can be attentive to only a small sliver of the world.

We’re constantly surrounded by so much noise, so many smells, so many different colors, textures, tastes.  The amount of sensory information that we’re bombarded with every moment would be overwhelming if we weren’t so good at ignoring our environment.

Consider smells.  Chemicals waft through the air, bind to olfactory receptors in our nose, and cause a signal to ping our brain: there’s the floral scent of an ethyl acetate here …  But, if we stay near the source of that chemical, our brain will keep receiving that signal.  Thankfully, this information is discarded by our subconscious minds.  As long as the types of smells in a space aren’t changing, we soon notice nothing.

If our clothes feel the same against our skin from one moment to the next, all the tactile information being sent from the surface of our body is similarly ignored.  But the information is still there.  If we focus your attention on your shirt, you can feel it.

The-Pearl-294878In The Pearl, John Steinbeck reveals how this glut of information can cause us to be hoodwinked.  A poor diver becomes suddenly wealthy when he finds a giant pearl.  The diver’s infant child was stung by a scorpion and has begun to recover … but a greedy doctor would rather the child receive an expensive cure.  The doctor knows that he can fool the diver by drawing his attention to details that never seemed important before.

It is as I thought,” [the doctor] said.  “The poison has gone inward and it will strike soon.  Come look!”  He held the eyelid down.  “See – it is blue.”  And Kino, [the diver], looking anxiously, saw that indeed it was a little blue.  And he didn’t know whether or not it was always a little blue.  But the trap was set.  He couldn’t take the chance.

If we scrutinize the world, we can always find something that looks strange.

#

When I was in high school, I had to get a medical physical each year.  Those cost $5 – a school nurse would measure my blood pressure, listen to my heart, and look at the curvature of my spine.  I felt healthy enough when I signed up for these physicals, and the nurses invariably agreed.  Even repeatedly-concussed football and soccer players were given a clean bill of health.

Queensland_State_Archives_2832_Medical_examination_with_the_School_Health_Services_October_1946

This $5 exam was insufficient to find anything wrong with us.  But if we’d been subjected to a $25,000 battery of diagnostic scrutiny instead, I’m sure we’d have seemed flawed.

Indeed, in a recently-published study designed to shill the new $25,000 physical from a company called “Health Nucleus” in California – which includes DNA sequencing, metabolite analysis, full-body MRI, two weeks of heart monitoring, and more – 40% of their seemingly-healthy study participants were diagnosed with “something seriously wrong.”  In several study participants, doctors found clusters of aberrant cells: pre-cancer.

In sexually-reproducing multicellular organisms, most cells carry DNA instructions to sacrifice themselves for the sake of the whole.  Some of these instructions code for contact inhibition, which means that cells stop growing when their edges bump into neighbors.  Other DNA sequences code for apoptosis, which means that cells commit suicide once they’re no longer needed.

But the mechanism for transmitting these instructions is imperfect.  DNA is copied again and again by jiggling protein machines called polymerases, and these make about 60 mistakes each time they copy our genomes.  Worse, DNA is copied from copies, so the mistakes pile up over time.  Like classroom handouts that have been photocopied from photocopies so many times that the words blur into static, DNA sequences that instruct our cells to cooperate can become unreadable.  At which point a cell is cancerous.

4.0.4Cancer cells continue growing without regard for the neighbors they’re crowding.  They carry on dividing – spewing forth copies of themselves – long after a team-player would’ve snuffed itself.

Most human adults harbor cancer cells.  All the time, they lurk in us.  And our immune systems destroy them.  Chemotherapy drugs do not kill cancerous cells – they slow the growth of all cells, giving a patient’s own immune system time to fight the menace.

So it’s unsurprising that doctors found pre-cancer in some of the study participants who underwent this $25,000 physical.  Study participants were as old as 98.  Their average age was 55.  After so much time alive, of course some of their cells had gone bad.

Early detection of cancer does boost a patient’s chance of survival, but sometimes in a trivial way.  Healthy patients whose immune systems would have destroyed a population of aberrant cells without any intervention … who might never have realized that anything was ever wrong … are counted as “cancer survivors.”  Extremely sensitive diagnosis can identify cancers early enough to be cured, but has the drawback of mis-labeling healthy people as diseased.

Every diagnosis of disease leads to harm – from worry, from the risks inherent in all medical treatment – and so has to be balanced against the expected outcome from doing nothing.  With some conditions, doing nothing would be deadly.  But by scrutinizing healthy people, you can always find something that looks strange.  Of course you’ll find “evidence of age-related chronic disease or risk factors” when you subject older people to a $25,000 battery of medical tests.  If you aggressively treat all of these, you’ll cause more harm than good.

maxresdefault

#

Because overdiagnosis can cause so much harm, the search for pre-cancer reminds me of the search for pre-criminals.  We can always find something wrong when we look hard enough.

I assume the researchers investigating children to find “pre-criminals” mean well.  I can imagine a world in which at-risk children are given more resources.  If it’s true, for instance, that a brief assessment of 3-year-olds or surveys filed by the teachers of 6-year-olds can predict future criminal behavior, we should cut spending on prisons and law enforcement to fund childhood nutrition, education, and enrichment instead.

Instead, we respond to intimations of future disobedience by watching people more closely.

Adorable Preschooler Playing with Colorful Dough

Our predictions of criminality become self-fulfilling: lifelong mistrust makes people criminals.  The racial injustice of mass incarceration is caused in part by unequal enforcement.  As far as we know, U.S. citizens of all ethnicities break laws equivalently often, but police scrutinize minority neighborhoods more closely, so that’s where they find crimes.

Similarly, when an elementary teacher decides that a student is trouble, that student gets scrutinized.  Equivalent misbehavior reaps unequal discipline.  In the U.S., children in preschool are targeted for school suspension based on the color of their skin.  A suspension disrupts education, pushing students further behind.  When a teacher decides that a student won’t learn, that student is prevented from learning.

And researchers have developed an automated image analysis that predicts the likelihood that someone is a criminal just from a photograph of his clean-shaven face.  Which isn’t as evil as it sounds.  Or, rather, it is evil, but not because a computer is doing it – the computer algorithm is simply revealing and quantifying the evil way we humans judge people by their appearances.

faces of criminals.PNG

Genetics differences are real, and they do make a substantial contribution to people’s proclivities.  But human brains are so plastic that the way we’re treated matters more: if you’re curious, you might want to check out this inadvertent identical twin study.

With a glance, we form strong opinions about people’s characters.  Some children we brand “pre-criminals.”  Is it shocking that, after decades of mistreatment and scrutiny, these children become the lawbreakers we always expected them to be?