Peter D'Adamo: Exemplars

You are a collection of cells (literally trillions of them) and each with a specific design and function. However, with a few exceptions, your cells all have a basic architectural design. Most of the time they are depicted as looking like a fried egg cooked sunny side up, but in reality they are three dimensional beings, more akin to a golf ball that you’ve cut across its midline. The “white” of our cell model is the body of the cell, and here are found many specialized areas called organelles that do particular jobs, much like our own internal organs have specific jobs as well. The “yolk” of our cell model is called the nucleus, and in this compartment there lies the object of our affections, the chromosomes.

Chromosomes were first discovered at the end of the 19th century by a German biologist named Walther Flemming. Flemming was looking at cells under a microscope and got the idea to use colors to dye the cell to make it easier to see things. The idea must have worked better than anticipated since he at once began to see spaghetti looking things in the nucleus that dyed a very deep color. As is the fashion, he named these entities chromosomes which is Greek for “colored bodies”.

Chromosomes are one of the more dynamic faces of Nature; they have to be, since they are responsible for the passing on of the 'Baton of Life' that we call reproduction. The number of chromosome in the cell nucleus differs somewhat from species to species. We humans have 46 chromosomes; dogs have 78; alligators 32; cabbage plants 18.

Your chromosomes are both the governess and chauffeur of the most important molecules in your body; DNA. Like any blueprint, DNA needs to read in order for the work order to be constructed. Now, DNA is a long, long molecule. If it were completely unraveled it would be about six feet long, yet so thin that it would be invisible, since you can easily fir one million cells on the head of a pin. If the entire DNA, in every cell of your body, was stretched out and laid end-to-end in a straight line, it would reach to the sun and back over one thousand times.

I think an effective way of describing the dynamic qualities of the chromosome is to use a few metaphors. My older daughter likes to knit, so we often visit the knitting supply shop in town for fresh yarn. Yarn usually comes wrapped in skeins, a length of yarn wound around a reel. Most yarn comes in lengths of 80-150 yards. One of the nice things about buying yarn this way, rather than just as one long unwound string, is that you can put it under your arm and walk to the car. This is certainly better than tying a knot to the rear bumper and pulled the unwound string all the way home. Thus, the first important lesion of chromosome dynamics; if you’re going to reproduce you’ve got to stuff that entire DNA into a very small, tight package. Chromosomes are just that: tight packages of DNA.

On the other hand, it is very difficult, if not downright impossible to knit anything if the skein of yarn still has the paper label wrapped around it. In order to use the yarn, you have to unwind it. That’s the formula: when the cell needs to use DNA to get information about how to make a protein, it has to unwind it. When it needs to reproduce, or turn off the DNA information flow, it needs to concentrate and condense it.

How this occurs is rather wondrous, and will be the subject of much discussion later on when we talk about how you can modify your genetic destiny, but for now we’ll just stick to the basics. DNA is packaged and concentrated by special proteins termed histones. This concentrated DNA is called chromatin, which is the DNA plus the histones that package DNA within the cell nucleus. Chromatin structure is also relevant to DNA replication and DNA repair.

Histones are very cool bead-like proteins that spool the DNA in a way that makes it either tighter or looser, sort of like the cardboard around which our skein of yarn is wrapped. Histones respond to changes in their structure by tightening the DNA wrap or loosening it. Whenever a cell needs to access the genetic information encoded in its DNA, the histones on the section of the DNA that is needed undergo a chemical reaction called acetylation by which a molecule called an acetyl group is stuck on the histones, causing them to relax and unravel. When business is concluded for the day, special enzymes come along and chomp off the acetyl group cause the histones to become de-acetylated, which makes them tighten up again, sending the DNA in the region back to its resting state. Think of it like this; when your DNA needs to work its histones chow down on acetyl groups for breakfast and they do yoga; when it needs to reproduce or shut down, the histones lift weights --the strain of which causes the acetyl group to pop out of their mouths.

Make sure that you’ve mastered the last paragraph, because much of the very cool stuff dealing with how you can modify gene functions pretty much requires that you know this stuff. By the way, this is very, very cutting edge material; only until recent times have we understood this mechanism, and of supremely paramount importance, that it is used by the environment to influence gene function and that influence, for either good or bad, can be passed on as inheritance.

Scientists have given each human chromosome a number, according to its size; thus chromosome number 1 is the largest, then number 2, etc. Chromosomes come in pairs, one from each parent. So there are 23 pairs, for a total of 46 in us humans. Numbers 1-22 are non-sex chromosomes called autosomes, and pair 23 contains the X and Y sex chromosomes.

In the few minutes it has taken to read up to here, this, around 400 million of your red blood cells were depleted and replaced, consistent with the set of genetic instructions contained in your DNA.

Many common folk also have a decidedly deterministic, perhaps fatalistic opinion of genetics. “It’s in the genes. There’s not much that you can do about it.” Nothing could be further from the truth; and although I can easily genuflect at the altar of genetics, I do not worship there. Your genes are just a reasonable plan for a particular way things can happen. Genes are just cogs in the wheel of life. They’re not here to cause disease; they are part of the structure of life.

For something so important to life, it’s quite surprising that there are so few of them; we humans have somewhere in the vicinity of 35,000 genes. Indeed when the human genome was first published scientists were incredulous to find that the number was so low (prior estimates were that there were at least 100,000.) And as if to prove that numbers aren’t everything, we humans don’t even measure up in this department as well; the average rice plant has around 40,000 genes. But then again, it’s not what you’ve got; it’s what you do with it.

It’s true, you can’t change your genes, but we are beginning to discover that Nature and Nurture do need each other. You can affect the way that your genes function. Matter of fact you do it all the time. For example, it may turn out that that dirty door knob your mother touched while she was pregnant with you may have had more influence in certain areas than all your DNA and RNA combined. As we move further into the meat and bones of this book, you will see how and why.

Genetics is typically thought of as being very complicated and difficult for the average person to understand, and this may well be true. However, the goal of this book is not to turn you into a geneticist, but rather give the advantages of conducting your life in such a way as to benefit from the knowledge of genetics.

Car showrooms can cast an interesting light on human behavior. While waiting my turn in a local dealership to buy a car, I had the chance to observe the interaction between the salesman and the young couple that he was attending to. Diligently he spouted out facts and details about the engine torque and horsepower, the suspension, and steering as the husband stood by obviously not understanding an iota of it all, but duly shaking his head and feigning great interest.

At the end of the soliloquy, our salesman of course asks if there are any questions. Not wanting to be seen as unintelligent, the young husband say no, he doesn’t have any. The young wife, on the other hand, had a burning question:

Where were the cup holders?

This simple interaction not only changed the way that I chose to write books, but changed my way of communicating in my medical practice. Most people who buy cars don’t want to repair them; they want to drive them. Yes, there is probably a very nice motor under the hood, but most intelligent people do not need convincing that there is a squirrel on a treadmill instead. For them the car is a means to an end; a way to get someplace. So, if you are willing sometimes to suspend disbelief that I am making this all up, I will repay the favor by spending the majority of our short time together teaching you how to get someplace with The Genotype Diet, rather than bludgeoning you with details that you could have easily gotten someplace else.

However, facts do make for the best stories, and I fancy myself a bit of a storyteller. However I do promise to try and keep the terminology down to a reasonable minimum, while keeping the nomenclature at the level where the names of things could at least serve as an interesting name for a pet.

“Here, Allele! Sit! Good doggy! That’s a good Allele!”

Gillian Roberts sent along this link to an interesting article about how the human genome changes with age. Sound like it is right out of The GenoType Diet if you ask me.

Although I’m probably only one of five people on the planet who have not read it, the blockbuster success The DaVinci Code is just another indication that we humans have an innate curiosity about codes and their relationships and meanings. This blog will take us into the ultimate code of them all: The Code of Life.

By general agreement, a code is a rule for converting a piece of information into another form or representation, not necessarily of the same type. For example, I often write computer programs, most often to do some particular job or another on my website. Most programmers refer to this a “writing code.” Computer programming code appears to the non-programmer as a series of arcane jottings and numbers, but to both the programmer and computer, this code is in reality a series of highly specific instructions, executed step by step, that result in the computer performing some real world action; perhaps posting a message to an internet bulletin board or sending along an email.

Since computer programs are often rather large affairs with many loops and computations, writing good computer code is a daunting -if at other times stimulating- pursuit. It can be reassuring to remember that at any moment in time only very simple, rather dumb things are happening. What makes the computer program so powerful is that all these simple dumb things are happening extremely fast with a tremendous degree of accuracy.

Very few computer programmers can ever claim to have written a perfect program straight off. There are too many places that things can go wrong, computers being the terribly literal creatures that they are. For example, a command that tells a computer to print Hello World! to the screen might look like this:

23. PRINT “Hello World!”;

Simple enough, eh? Like the way we humans typically read books (from front to back and top to bottom) computers execute code from the top down. Thus, our line of computer code is numbered 23, so we can assume that there are twenty odd lines of computer code in front that will be executed before our screen lights up with the words “Hello World!” Perhaps line 22 tells the computer to make the screen font red, in which case our “Hello World!” would be rendered in red colored type. If we remove that line and run the program again, our font color goes back to black.

Look at our line 23 again and you will notice that the phrase you see -- Hello World! -- is in quotes, because in our simple computer language putting a phrase in quotes tells the computer where is the beginning and end of what you want sent to the screen is located. Without this type of instruction, computers are actually quite dumb, and have to rely on us to tell them where the beginning and end of various human things lie. Also notice that at the end of the line is a semi-colon, which in our little computer language tells the computer that this is the end of that particular line of code, so move down one line and execute that command next.

Computers are so literal that a mistake of even one character can cause a program to malfunction. For example, if you saw this line:

23. PRIINT “Hello World!”;

You’d probably guess that something is supposed to be printed. However the computer does not see PRIINT as the equivalent of PRINT. On the other hand if your code looked like this:

23. PRINT “Hello Wurld!”;

The program would probably still execute, since as far as the computer is concerned the command is correct and it’s in quotes, so it assumes that this is probably what you wanted. Once the command is correct, the computer doesn’t care if you tell it to write “Hello Wurld” or “Kick Me”. As long as its own language is correct, the computer will chug happily along, performing its assigned tasks.

Like computers, first impressions, and that light switch on the bathroom wall, genetics is remarkably digit business: On-Off; Yes-No; Love-Hate. So even if it looks complicated at times, don’t be fooled: It’s not. Just remember, like computers, genetics is simply a lot of small things happening in a clear-cut manner and if you get perplexed or lost, just take a step or two backwards and start again.

The mechanism of the genome is surprisingly similar to our simple line of computer code; so simple in fact that I will provide you with an “executive summary” of the whole affair in just two paragraphs.

A molecule called DNA periodically assembles copies of various parts of itself that are called RNA. RNA then travels to other parts of the cell where it is read as an instruction template, assembling chains of amino acids into something very useful: protein molecules of delightfully complex three dimensional shapes that are most often a class of proteins called enzymes.

Enzymes are special speed-up molecules that greatly foster the production and metabolism of the body’s tissues and secretions. Without them many biochemical reactions would occur so slowly as effectively negate their value. Just think about the difference between soaking a dirt stain in plain water for four days, versus soaking it for four minutes in a solution of water and laundry detergent and you’ll get an appreciation for the action of enzymes.

Enzymes catalyze many of the reactions involving proteins, fats, carbohydrates and minerals. Hormones, mucus, neurotransmitters, you name it; they are all made from enzymes.

Bingo. Life.

It sobering and a bit humbling, to ponder the fact that when we eat any kind of protein, we’re actually consuming the results of something’s DNA and some of their DNA as well. However we usually break down dietary proteins to their amino acid building blocks and start all over again.

Occasionally, wild molecular gyrations occur as the incredibly DNA long molecule prepares to replicate by winding itself up tighter and tighter on a tubular scaffold of its own creation. Splitting from the ends much like an old Manila hemp rope would, each of the two unraveling single strands then begins to assemble a copy of its missing partner, producing two unique strands of DNA and creating two daughter replicas from one original.

What happens is surprisingly simple. Good things are like that; a strong underpinning of fact and analysis, and a veneer of simplicity and common sense. Now why, on the other hand, is quite a different story.

The year 1956 stands out in my mind for a variety of reasons, the most important being (at least for me) that it was the year I was born. It also marked the year of the only ‘perfect game’ even thrown in a baseball World Series. Music fans might remember that it was the year that Elvis Presley entered the United States music charts for the first time, with 'Heartbreak Hotel.'

1956 was also the year a scientist named Roger Williams published a book called Biochemical Individuality, which attempted to relate inherited individual distinctions to nutritional requirements. Although Williams was no small figure in medicine (at the University of Austin he had discovered pantothenic acid, one of the critical B vitamins, and had published skews of articles detailing some of the most basic biochemical discoveries) Biochemical Individuality attracted little, if any attention from the medical community, probably due to the fact, as Jeffrey Bland speculates in his book Genetic Nutritioneering, Williams expressed many of his ideas in biochemical terms, which doctors of the time were far less comfortable with compared with today.

How prescient is the following phrase:

“The existence in every human being of a vast array of attributes which are potentially measurable (whether by present methods or not), and often uncorrelated mathematically, makes quite tenable the hypothesis that practically every human being is a deviate in some respects.”

It’s a strange choice of words, but the word deviate in this context signifies a turning away from the normal or a variance of some sort. Of course, we tend to think of the word more as a term for individuals who deviate from some sort of social norm; but norms are norms.

Williams was certainly deviating from conventional medical wisdom. Nobody at the time was looking at peculiar and individual aspects of nutrition that might be predicted genetically. More importantly, in 1956 there wasn’t anywhere near the enormous genetic industry and technology that exists today; it had only been three years before that James Watson and Francis Crick deduced the basic structure of DNA, (Deoxyribonucleic acid) –the double helix-- that contains the genetic instructions specifying the biological development of all cellular forms of life.

Thus when Williams talked of “attributes that are potentially measurable (by present methods or not)” he is taking an amazingly huge step into the future.

So Williams’ phrase “often uncorrelated mathematically” should probably be reinterpreted to mean “we can’t see the connections because of our current puny computational abilities.” Nowadays we link supercomputers together into vast neural networks and process data at a speed and accuracy that just boggles the mind. It was just this type of muscular computing that allowed scientists like Craig Venter and his firm Celera Genomics to help crack the human genome in record time. Today, the combination of gene sequencing and supercomputers is a day to day event in hundreds of laboratories worldwide, and is a prime part of a vast new field called bioinformatics.

In 1956, nutrition science was still in its infancy, concerned mostly with deficiency types of diseases such as pellagra and anemia, and making sure that we all ate “balanced meals.” There was no link between diet and cholesterol or between cholesterol and hardening of the arteries and medical journals often featured cigarette ads on their back pages. Ulcers were often treated by telling the patient to drink copious amounts of milk, the so-called “sippy-diet.” In other words, nutritional thinking at the time was predominantly disease-based, which is odd, since almost everything we do with food has absolutely nothing to do with disease. This resulted in what my friend and colleague Jonathan Wright used to call "The Association Diets.'

This is not to say that pieces of the puzzle weren’t evident, or that intelligent people were not already beginning to ask the right questions. It’s just that the questions could only be based on what was thought to be known, and what was known was not very much.

I can remember taking a computer class in high school (already well into the 1960’s) where we were taught to diligently inscribe a series punch cards with a 'number 2' pencil, which were then collated and fed to a machine the size of a large refrigerator, which then hacked and coughed for a while, finally yielding a half page printout of a list of fifty prime numbers.

Unless, of course, you had the misfortune to have penciled in the wrong box, in which case you just started all over again; a frustrating experience, which lead to one of my young colleagues, in a rage of frustration, placing one of the cards on the floor and proceeding to stomp on it repeatedly with his shoed foot, sending it on to the card reader --and probably producing the first computer virus-- a trick many of us would repeat when similarly frustrated. Your home computer can do these functions in micro-seconds, and the software to do it is considered so basic that it is usually packaged for free with the operating system.

Eye color is far more complex than is generally appreciated, ranging from blue, gray, green, green/blue, brown, and others, varying with different populations. As with skin pigmentation, eye and hair color results from the degree of melanin pigment deposited in the tissue. Humans have several eye color genes. Two best understood are named BEY2 (brown eye) located on chromosome 15 and GEY (green/blue eye) located on chromosome 19. Interestingly, the human “secretor” blood type gene is linked to the GEY gene, since they are both found on chromosome 19. This may explain why the percentage of secretors in the population rises as one heads further north, since the percentage of green and blue eyes increases as well.

There is one peculiarity of eye structure which has been used in making racial distinctions called the epicanthic eye-fold, a fold of flesh that covers the upper eyelid, and sometimes even the upper eyelashes, when the eyes are wide open. It gives the eyes a narrower appearance. It may be an evolutionary defense against both the extreme cold as well as the extreme light that occurs in the Eurasian arctic and north. It has also been suggested that the fold provides some protection against dust in areas of desert such as that found in the deserts of northern China and Mongolia as well as parts of Africa.

Although almost universal amongst Central and Northern Asians, there is a wide distribution of the epicanthic fold across the world. It is also found in significant numbers amongst Amerindians, the Khoisan of Southern Africa and some people of Sami (Lapp) origin. The presence of epicanthic folds is common in many, though not all, groups of East Asian and Southeast Asian descent. Due to classic genetics children of a parent with a pronounced epicanthic fold and one without an epicanthic fold will have varying degrees of epicanthic folds as a result. On the other hand, high orbits, with no folds, are characteristic of certain Balkan populations and of most Near Eastern peoples.

Hair texture is measured by the degree of fineness or coarseness, which varies according to the diameter of each individual hair. There are four major types of hair texture, which are fine, medium, coarse and wiry (sometimes referred to as wooly). Head hair grows at the rate of approximately 1.25 centimeters, or about 0.5 inches, per month, and it has been speculated that the significance of long head hair may be adornment leading to what evolutionary biologists call “Fisherian Runaway Sexual Selection”, in which an prospective mate’s health is gauged by lustrous hair, leading to a greater rate of selection for those individuals with the gene –the same mechanism that probably led to those beautiful peacock feathers.

Scalp hair varies tremendously between races; the scalp hair of most Asians has the greatest thickness and the roundest cross-section, which produces a thick, straight hair. In Europeans the hair is more oval and finer; in Negroes it is flattened, resulting in small wiry, or “kinky” curls. There are at least three kinds of kinky hair. There is short kinky hair that covers the whole scalp evenly, as with most African peoples. There is short kinky hair that grows in tufts with seemingly bare spaces between, as in some East African groups. Then there is the longer kinky hair of the peoples of the Southwest Pacific islands. The hair of the Australian Aborigines is curly or wavy, except for one small group in Queensland who have what is called "frizzy" hair, or hair that is slightly kinky. It has been speculated that wiry hair texture has an advantage in being difficult to penetrate by stinging insects and tends to wick sweat effectively, keeping it away from the face, two distinct benefits in hot, humid environments. Only persons of African descent usually have this type of hair, although some Europeans can have extremely curly or frizzy hair.

Blonde hair is produced by an absence of melanin and may be attempt to optimize UV penetration of the scalp (maximizing vitamin D levels in the northern climes)

Having red hair is associated with the recessive version of the MC1R gene on chromosome 16, which also codes for fair skin and freckles. Four out of five redheads have this gene variant, which is found at its greatest frequency in Scotland and Ireland. Some authorities suggest that red-haired people may be descendents of a blending of Neanderthal and Cro-Magnon peoples while others suggest that the gene is more recent, well after the human migration from Africa, so that the geographical distribution of red hair would be due to post-glacial expansions from Europe.

The tendency of the two eyebrows to blend over the nose, called “concurrency” is found in its highest frequency in the Middle East, but is also common among Southern Europeans.