Genetic breakthrough that reveals the differences between humans

[Michael Stuart Kelly]

Genetic breakthrough that reveals the differences between humans

by Steve Connor, Science Editor

November 23, 2006

The Independent

I love news like this.

Michael

[Barbara Branden]

Michael, am I correct in thinking that you see a meaning in this discovery apart from its implications for the understanding of disease? If so, what is it that you see?

Barbara

[Michael Stuart Kelly]

Barbara,

I see the door opening to increasing longevity, increasing bodily health and increasing mental capabilities through technologies like this, especially when a former limitation is overcome and a new model (the extra copies mentioned in the article) is discovered and cries out to be be explored.

Let's say that instead of looking only at remedying what is bad, I see potential for strengthening and improving what is good.

Michael

[kiaer.ts]

Press Releases and Supermarket Shelves

While I wouldn't want to minimize the meaning of the underlying facts here, this announcement has all the trappings of a press release, as opposed to that of a truly fundamental breakthrough.

Most people have at least two copies of any gene, one from each parent. The genes specify the exact version of a certain protein molecule, which will either, like keratin in skin, be used directly to build our structure, or will, like a hormone, regulate the production of other proteins and biologically active substances in the body.

Many genetic diseases like dwarfism are caused by having one good copy and one non-functional copy of a specific gene. Dwarfism is caused by having only half the normal amount of a growth regulator gene. Having two bad copies of that particular gene is always 100% fatal. Similarly, sickle-cell anemia is caused when a person has two copies of a mutant gene that effects the structure of red blood cells. Having only one copy of this gene actually has benefits for those who live in malarial areas, because they are less susceptible to the effects of that disease. But if two people with one copy have children, one quarter of their children will inherit a bad copy from each parent on average (1/2 X 1/2= 1/4) and they will suffer the crippling effects of the sickle-cell anemia. The gene does not disappear, however, because it is so beneficial to those who have one copy in tropical areas that it is "worth the chance" evolutionarily speaking for the gene to stay in the gene pool.

Other genes, such as those for melanin, have long been known to exist not only in various versions, but also with varying numbers of copies of the gene. One can have dark skin from having a few "black" copies or a bunch of "brown" copies of that gene. The same sort of thing applies for genes that specify eye-color and many other traits that are able to vary without making their carriers unhealthy or sterile. And keep in mind, of course, that a "white" person with a tan can be darker than a "black" person who avoids the sun.

But having too many copies of a gene or genes can be just as bad. Some cases of chromosomal genetic mutation (such as in Down's syndrome and various XXX or XXY syndromes of the sex-determining chromosomes) result in the triplication, rather than the normal duplication of the copies of many genes. The extra chromosome in these cases can be deleterious or fatal, or can lead to the failure to reproduce or help raise children, which so far as genetics is concerned, is no different from fatality.

What is being trumpeted here is not a totally new discovery, but the results of what is in essence a statistical study. It confirms and emphasizes what has long been known and points research toward what the layperson can best understand as the benefits of having redundancies and back-up copies. The immediate effects will be negligible - except perhaps for where research grant monies get channeled.

What the layman needs to keep in mind are two things. First, there are no genes "for" anything except genes for proteins. The proteins can be broadly classed into structural and regulatory categories. (Keep in mid that this is quite an oversimplification.) Proteins can be analogized to the structural and design elements of a very complicated building or transportation network. Some proteins, like stoplights and front doors are vital, and some, like lane width and light fixtures are quite variable. Some cannot be done without, some can be bypassed or detoured in an emergency, and some might never even be missed. Whether we classify humans as being 99.44% or just 90% genetically identical, genes are like blueprints and recipes, not brick-layers or baking batter. Having just one single gene out of many thousands that malfunctions or confers advantage can mean anything from a zero to a one-hundred percent difference in life outcome. The second thing to remember is that there is a long and complicated chain of causes and events between press releases and supermarket shelves. Michael's hopes are not at all misguided; but this announcement is a trial ballon, not a declaration of victory.

Ted Keer, 23 November, 2006, USA

[Michael Stuart Kelly]

Like a friend just wrote wrote to me, there is a tad of development between Newton and production of the automobile. Call my enthusiasm cheerleading for the scientists with a view of what is to come.

Michael

[kiaer.ts]

Mike,

I have no problem with cheerleading, I just wanted to put the issue in perspective given my interest in and my knowledge of biology. I figured that my comments would give the post some context which non-scientists would appreciate.

The stumbling block before those of us living is, if we do not already have the right genes ourselves, how do we take advantage of the knowledge? Gene therapy is about as advanced right now as our ability to colonize Mars. Even if we can identify the good genes, we have no way to insert them into the right cells and no certainty that doing so won't cause worse problems, like cancer, than the proposed therapy. The answer to the conundrum is, ask again in a decade or so, if we are still around to ask. And don't lose hope either. Look at what has been done with AIDS and certain cancers recently. If you really wish to speculate, check out Ray Kurtzweil's The Singularity is Near. He's the same Kurtzweil of keyboard fame, but is also a fascinating speculative genius. His theories on artificial intellingence are unfortunately based on false premises (reductive materialism, mixed with the fallacious theory of mind as a floating abstraction run on a computer, known as "strong AI") but he is still a genius and he's looking for some interesting fruit, just not always up the right tree.

Ted Keer, 23 November, 2006, USA

[omphalos]

Ted makes a good point which, to my knowledge, has *never* been adequately explained to the layman.

Genes are instructions for construction. That's it.

Two recipes for mayonnaise may appear almost identical, but the one which reads "slowly beat eggs into oil" will fail; while the one which reads "slowly beat oil into eggs" will succeed.

The recipes may be identical to 99.99 percent, but if this crucial instruction sequence is mixed up, you ain't getting mayonnaise, no way, no how.

[John Dailey]

Ted:

~ I caught an interview with Ray Kurtzweil on C-SPAN/Book-TV a couple weeks ago, and, you're right. 'Genius' barely describes him re the breadth a-n-d depth of the subjects he gets into.

~ Haven't obtained any of his books yet, but do plan to. He's clearly up on his genetics, but, given his interest in the coming interface of humans and AI (can one say 'cyborg'?), he'd have to be. I, also, suspect that he's counting on too much re AI's present knowledge-development per se, but, I'd not discount its relevence totally.

LLAP

J:D