Sunday, November 14, 2010

On Evolution: You are a Mutant

[Note: a good chunk of this text is from old stuff I'd written on this and at least two other attempts at science-oriented blogging.  It's critical to note this post is an exercise to write for absolute beginners with zero knowledge of science. 

Anyway, with little feedback (no one came, no one saw, no one, um... critiqued), I guess I kept giving up.  However, I keep going back to these old bits and re-working them with new introductions, new frameworks, etc.   So here it is again.    I have a bunch of the other chunks that follow this which - I feel - make a complete story.  Just need to work out the kinks.   Now about that feedback...]

A few years back, there was a debate about evolution, given in front of the general public and broadcast live on TV. It was really an Evolution vs. Christianity debate, which I really find to be horrible messes to watch. Usually they involve fact-based people expressing facts and very literal interpreters of scripture using a huge arsenal of rhetorical tricks to essentially ignore each fact presented and create plausible doubt for the audience.

In such cases, I view the scriptural literalists to be a lost cause. Fact and honest discussion are irrelevant for them – either because they believe their literalism deeply - and that’s that, or they don’t really believe what they’re saying but know how to twist a good word into a bad one.

Regardless of those particular types, the impression these debates leave with the general public - you and I and everyone else that simply wants to know what the deal is with the world and everything - are still important. And that’s why I was particularly dismayed when a chance to clarify one particular point of confusion was so sadly lost.

So, in the middle of this debate, the moderator asked what is really a critical question, in terms of the misunderstanding of biology and evolution. He may not have intended it that way, but when he asked it, I was shocked because, while I knew evolution is badly - tragically - misunderstood, I hadn’t realized people thought this particular point of way-off-baseness.

This question asked by the moderator to a defender of evolution was this:
When you were born, you weren’t transitioning from monkey for the first 5 years, to human being for the next 10… The argument you just made was that everybody in this room is a transitional creature… and what I’m asking you is: explain to the audience what they were - when they were born - which is different from what they are now.
(Debate play list is here. The part with this question is here, at around minute 3:05)


The defender attempted to clarify his point to the moderator by mentioning (under stress of the moment, I imagine) that “people evolve over time, all animals evolve over time” and then recounting the various growing number of key pre-human species found in the fossil record, mentioning the names of one of them, Australopithecus afarensis.

OK, as I sidebar, I have to ask: did you black out with those last two words?

That's ok, because I think it's a common reaction most people have when asking a basic question that  gets an answer already dripping in scientific wording.  People aren't expecting it and aren't prepared for it... and they start to shut down.   Usually it's better to get into the details - the special names and deeper subtleties of a subject - after you've already cleared up the basics of the subject at hand.

But that isn't the big problem with his response. (and here I end my sidebar comment)

The problem with the defender's response was that "Australopithecus afarensis"  wasn’t the answer to the question being asked.

Also the statement "people evolve over time" was actually adding fuel to the source of the question in a very bad way.

What I mean is this... The question I personally heard in that exchange - not said, by any means, but what I felt to be the essence of the question - was:
“I was lead to believe that evolution claims we’re all changing - evolving - from our birth to our death. This is counter to the observation that, other than aging, I am the same human I always was. Therefore I find the whole concept of evolution to be suspicious and hard to believe. Can you help me understand otherwise?”
To this question,  "Australopithecus afarensis"  is meaningless and "people evolve over time" only reinforces the misunderstanding.

In fact, while listening to the exchange collapse after this, I was almost screaming a response:
Nothing is different about YOU. Everyone, me and you, all of us - (pause for hyperventilating intake of breath) -  Nothing about us, our personal body, has changed - other than the alterations of growth and ravages of time. Nothing.
And I can’t help but feel the audience lost the thread when that actual question wasn’t really answered. (Yes, I know watching a video and saying that is different that being on a stage in the heat of the moment.)

The problem was there was a point that could have been made - perhaps a clarifying moment for some in the audience - to wipe away one of the very many misunderstandings surrounding evolution.

Neither you, nor I, have ever (in the biological sense) evolved.

You were born, you live, you die.

And, genetically speaking, the essence of the physical “you”, your body, is a result of that one one event, when you were first conceived. What your body became was locked in at that moment. Yes, environment and other factors have their roles - some quite dramatic, but the genetic component is the core of it all.

From birth to death, YOU do not evolve.

But... when you were conceived and then born, there was something different about you. Something that does have to do with evolution.

I'll tell you what it is...

YOU ARE A MUTANT

You’re a mutant.

You are, and were, from the very beginning of your genetic existence, someone that was built with mutated stuff.

Here’s a bit of what I mean - just a little bit.

You were given half of your "instructions for building you" by your father and half by your mother.

One might think that if your Dad compared those instructions that he gave you to the those with which he started life, that they would be a perfect match. And they probably would be.

Nearly perfect.

Nearly.

But not quite.

At the least, what he would actually find is that the instructions he gave you had a couple of hundred tiny errors, scattered randomly throughout. A similar fact is true for your mother’s contribution as well.


This is something that has been long calculated and quite recently, with very powerful technology, was solidly demonstrated to be fact.

The instructions that your parents gave you have a couple of hundred errors.

These errors are called mutations.


So - without question – you are a mutant.




THE BOOK

To think about this, let me just describe some background with one of the many analogies that get used:

The term "DNA" is the real name for what I'm describing, with some license, as a "book of instructions".  It's written in a simple alphabet: this one having only 4 letters, unlike English, with its 26.  But even with 4 letters, there are comparable rules for what makes up a word in these instructions and which words have what meaning.  What those rules are don't matter right here - but just know that there is a robust logic to the DNA alphabet.

Now, this instruction book is sometimes described as a “blueprint” of your body. However, that’s a bit inaccurate. All your book really contains is the diagrams to make a wide variety of tools and materials that are, generically, called “proteins”.

And it’s these proteins, each one described in your DNA instruction book, that work together, in a highly intricate dance of interactions and combinations, to build you.

So, again:
● DNA is the instructions, written in a simple alphabet, that says how to build proteins.
● Proteins are the things that actually go about building you.
OK… given that background, what is a mutation?



A NEARLY FAIR COPY

The most basic description of a mutation is: any change somewhere in the DNA instructions.
There are many types of changes that can happen, some massive and some almost imperceptible, but I’ll focus on the simple ones.

Imagine someone has your book of DNA instructions and is given the task of making a copy of the whole thing by hand. (And in fact, this copying happens all the time in most of the cells in your body.)

OK, so, the guy who’s doing the copying is pretty darn good. He rarely makes mistakes and he’s also very diligent at double checking his work so as to correct the occasional error he does make.

So the copy is really, really pretty darn faithful to the original.

But… it’s a big book. It's a few billion letters long.

Once in a very, very long while, the copying guy misspells a word (In the alphabet analogy, say, “cat” is copied as “car” or “kat”) and also happens to not notice the error, so it doesn’t get corrected.

Once he’s moved on to later pages of the book, there is no going back. The error is now a permanent part of the copied book.

That’s a mutation.

Other times, he might accidentally delete or add one or many letters. (In the analogy, “color” becomes “collor” or “colour”)

These are also mutations.

Aside from these, there are far more elaborate ways that changes in DNA instructions happen, but these basic ones illustrate the point, I think.



PASSING THE CHANGES ON



And here’s where the difference between your parents’ DNA and your DNA comes up:

See, both your father and mother were built up using the instruction books they were born with.

And as the years went by, eventually, your mother-to-be started making eggs and your father-to-be made sperm – the two things that, together, make a child.

Each round of “making cells” is, in fact, a round of copying the DNA instruction book and putting it into a new cell. And each round of copying has that chance of a mistake being made, somewhere, nearly randomly.

That chance, again, is low. But over the years, the copying happens often enough that the errors happen enough.

And, so, for an average, say 30-40 year old man, enough rounds of copying have happened that a hundred or so random errors – mutations - have crept into the instructions contained within any given sperm cell. Similar events are true for any given egg from the mother.

In theory, then, nearly every egg and sperm is probably a mutant, compared to the mother and father that made them.

And then one sperm and one egg meet and, of course, that’s the start of a baby. A baby with a couple of hundred mutations!

You. Me. Everyone.

We are all mutants.

---

And yet most of us are not particularly unusual compared with anyone else, to the best of our knowledge.

Why do I not have six toes, or something equally, um, mutanty?

In the next post in this particular series, I will follow-up by explaining why having mutations, usually, does not affect your basic humanness (or any other animal's animalness, or a plant's planitness.)

(Click here for that eagerly awaited post!)




You do not change.  You are already changed


But I’ll end the post with this:

You do not evolve.
No one of us was born one way and then later evolved into some other animal.
Evolution doesn't work that way.

We do not change.
But we arrived already changed.
And so do our children.

So, in a sense, you are just a single step. We all, as a generation, represent this step.

It is the most tiny of steps. But it is of significance.

And, in the same way that you are a step, we - each of us - has inside us the seeds of the next tiny step.
The next 4 mutants have been born this past second. They are part of the next step.

Where these steps are going is always unknown when they are new.

If we look back from the future, say thousands or millions of years, we may see the steps form a roads from here, going down some gently drifting direction for a long while.  And then, we might see our road abruptly turn some corners, or perhaps get wider or narrower. More dramatically, there may be parts down the road that split to the right and left, with each road beginning independent meanderings. These new sister-roads both might continue weaving and branching for ages. Or one of them might just suddenly... stop.

You are, and I am, part of a single step in that road.

Look at the people who made that road from our current step and then look at those from some way down the road: you will likely see subtle differences between them and us, perhaps barely perceptible.
Now look way, way down the road, especially where it sharply turns or splits: look at the people that make up those steps, and you might see more dramatic changes.

That seemingly endless and often aimless mess of a roadway *is* evolution.

No goal.

It just goes on.

It survives.


Give this cycle the thousands of millennia it has had to repeat itself - coupled with other events, to be discussed later, that give apparent direction -  and there you have the change you are looking for.

The evolution - the change over time - is not us.

But we are, indeed, part of the change.


(Go onward to the next post of this subject here: Quiet Accumulations)

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