RICKY GOES TO COLLEGE

Chapter 2: Genes, Brain, and Environment / "What is the impact of the environment on the brain?"

[ An outline: black text = via course documents; blue text = me injected; brick text = my brain looping. ]

Mendelian Inheritance (George Mendel, 1866)
1) For each trait, offspring inherit an "element" from each parent.
2) An element that is dominant is "apparent" or expressed.
 An element that is not dominant is "recessive."

Mendel unknowingly imagines the workings of inheritance, without comprehending anything about the actual mechanisms involved. It would be another fifty years before his work would inform the beginnings of classical genetics.

The "elements" are genes, small sections of DNA that produce specific 3-D proteins, which in turn form the building blocks of our bodies and drive the processes that allow us to live.
(...so says the text—they actually compel us to live.)
Genotype = genetic code carried by an organism.
Phenotype = observable structure or behavior of an organism.

Explicit (phenotype) and Implicit (genotype) information :::
The explicit is an expression of the implicit.
And so, phenotype is the revelation of the genotype.

Complex Inheritance—combinations of genes working together to produce an effect.
Actually, "simple" inheritance is enormously complex in itself.
Consider that the DNA encoded in the 10 trillion or so cells in a human body contains complete instructions for expressing the body (fertilized egg growing furiously into conscious being), and then directing and facilitating it throughout life (processing 10,000 different precisely enfolded and functioning proteins; constructing eyes that see; brains that think; mouths that speak...)

By affecting our brains (structurally, chemically, functionally) genes can also affect our behavior.

In a '96 experiment by RYNER, a single gene is altered and affects the targeted sexual attraction of insects.
The genetic change alters what they desire. In complex information systems, SMALL changes = LARGE effects.
Likewise, the genetic coding, or the "books" of the human and the chimpanzee are 99% identical.
(Think of it: a pair of 100 page books where 99 of the pages are worded and punctuated in exactly the same way, with only one page of variations.)

However ::: It's not nearly that simple!

The PHENOTYPE is not a straight "read-out" of the GENOTYPE.
Genotype, for example, determines the potential structure of your brain, but not the resulting structure in its entirety. While an acorn will always grow into an oak tree, with oak-shaped leaves and oak-textured bark and mathematically determined branching patterns found in nature—we cannot map precisely the individual oaken characteristics of a certain oak tree from a particular acorn.

By interacting with and growing within an environment, the brain:

1. Loses neural connections it had at birth.

2. Retains those connections used frequently.

3. Eliminates, through Pruning, those NOT used frequently.

Such changes are called Plasticity, as the brain and its connections are molded by experience and external forces.
For example, an enriched environment that provides sources of interest and interaction result in a "heavier" brain,
the added weight a product of increased blood flow to the cortex and the formation of new connections.
On the other hand—an impoverished environment will turn a brain into a tepid bowl of oatmeal.

Plasticity is displayed :::

1) When interactions with the environment shape the brain during infancy and childhood.

2) When the body changes so that the sensory input changes.

3) When we learn something new or store new information.

4) When compensating for brain damage. (Other areas taking over lost functions.)

"Genes are not destiny..." They do not set characteristics, but rather they determine what is possible—
outlining general parameters and pathways, as opposed to defining a precise or particular future outcome.

And now, the rest of the story...

Genes not only instruct the fertilized egg that contains them how to go about unfurling...
a brain that is so deeply complex that it gives rise to the amazing quality we call consciousness, but in their various configurations genes also "know" how to survive a forest fire (a stand of trees); how to grow in five-way symmetry (a starfish); how to grow while maintaining the same shape; how to write a symphony; how to evolve...

[We pause here for an overflowing page 4.]

A few weeks ago I mentioned that in the realm of information theory, "1+1=3."
In a more accurate sense, two SETS of information, when combined, give rise to new and unforeseen
phenomena, such as the QUALITY of depth perception from combining the view of two separately
positioned eyes. In the brain, millions of "1+1" combinations all add up to the "3" of self-awareness,
and therein lies the importance of tying together as many parts of the world as possible, in order to add clarity,
comprehension, and depth of consciousness.

Let me RUN you through an example of how this works for me :::

[ image 1 ]

A very small section of DNA, just to show its double helix structure, a ladder in spiral form.
The line on the left is one vertical turn of the spiral, 34 angstroms long.
An angstrom is unimaginably small, and is used to measure the diameter of atoms,
one angstrom being the diameter of an "average" atom.
There are 250 million angstroms in one inch. So, 80 million or so of these DNA snippets per inch.
This segmented line on the right? That's the same 34 angstrom length, but notice
it's in two sections—more on that in a minute.
I show you this both because it's beautiful, and because it's laden with meaning.

[ image 2 ]

Lower right, snaking in, the double helix again—your DNA, of which each cell in your body
has two incredibly slender meters worth (!!!) which fits by wrapping itself many several different ways,
so that the two-meter strand ends up being 1,000,000th of a meter long, weighing about 6 trillionths of a gram.
By the way—while we're speaking of "scale" and trying to envision all of this: If all of the empty space inside the atoms in our bodies was removed, you could fit the entire human population inside the volume of one sugar cube. (And the "stuff" we're made of isn't really "stuff" at all, but that's another story.)
There's really nothing more incredible than reality.

[ image 3 ]

This is how DNA, wrapped around those crazy histone molecules, looks wrapped around a chromatin fiber.
Before wrapping and folding further a few times. Ridiculous, isn't it?

[ image 4 ]

Back to our dear friend the double helix—the 34 angstrom length of DNA.
The segmented line is measuring the MINOR grooves (inside the ladder)
and MAJOR grooves (outside the ladder) of the vertical spiral.
The line is called a GOLDEN SECTION in mathematics, because it's PERFECT.
The length of the short (13 ang) compared to the length of the long (21 ang)
is the same as the length of the long (21 ang) compared to the length of the whole (34 ang).
(Say it again.)
This ratio, as it turns out, is how nature builds spirals. And much more.

[ image 5 ]

Perfect is Perfect. The Greeks began using the golden section, or "Divine Proportion" in architecture and sculpture a few thousand years ago. The lengths of the lines and the rectangular AREAs of the Parthenon are in this ratio.
We still use it today in art and architecture and mathematics and... everywhere.
By the way, the ratio is PHI. ("Peiy")

[ image 6 ]

And in nature: the VOLUMEs of the chambers of the chambered nautilus grow in accord with this formula.
Cut an artichoke or a stalk of celery or a rose bloom at the base and you'll see the spirals of petals or leaves working in exactly the same way. It determines tree branching patterns, the turn of spiral galaxies, the patterns of sunflower seeds or pinecone scales, and the angled "tiling" patterns of soap bubbles, which are identical in shape to the plates in the shell of a turtle, and it goes on and on and on...

[ image 7 ]

Leonardo da Vinci's "Vetruvian Man," which uses geometric golden sections in various ways to define
the ideal proportions of the human body. You can look it up. And you should.

[ image 8 ]

Aphrodite, the Greek goddess of erotic love, beauty, and fertility,
sculpted in accord with the divine proportion.

[ image 9 ]

Here is a contemporary example, Salvador Dali's "Sacrament of the Last Supper," with apostles dissecting the lines of the table at the exact proper places (Vitruvian Man's outstretched arms echoed in the vault of the ceiling), golden rectangles again rampant in the composition; and a DODECAHEDRON, of all things—a twelve-paned solid with pentagonal sides that is a kind of boiling golden-section stew, which brings us to...

[ image 10 ]

A Dodecahedron (of all things!) being spun vertically and proportionally and revealing the structure, symmetrically once again, of the double helix.

And if you are capable of opening to some of this, then I have just created an ENVIRONMENT humming with conceptual connections, that may have forged a few new neural connections for you, and thus altered—hopefully in some thrilling and expansive way—your hungry little BRAIN.

...Genes also continue to function in other capacities, making your hair fall out both randomly and in patterns, gumming up your arteries, deciding when its time to inject your Grandmother's arthritis into your joints,

Although it may be convenient to talk about Genes and Environment as separate factors or discrete entities, they are actually different aspects of a single system. It's extremely important to note that, when it comes to the "whole picture," this is also true of every "thing" in the SYSTEM we refer to as The Universe.

Genes can affect the environment / The environment can regulate the genes.
It's a SYSTEM!

There are three ways that the genes and environment interact [Plomin '97 / Scarr & McCartney '83]

1) Passive Interaction—when genetically shaped tendencies of parents or siblings create an environment that is passively received by the child.

2) Evocative (or Reactive) Interaction—when genetically influenced characteristics draw out or elicit behaviors from others.

3) Active Interaction—deliberately choosing specific situations, and aggressively avoiding others. Constructing, shaping, or modifying situations that fit with existing genetic tendencies.