The idea that human beings are as capable of evolving as any other species
has taken most of the last 150 years to become acceptable (except among
religious fundamentalists). However, the possibility that human beings
would be able to consciously direct their own evolution -- 'designer-baby'
style -- was finally dashed soon after the first draft of the human genome
was released by the Human Genome Project in 2003.
It was then realized that genes no longer act alone. In our body cells,
each of us deploys about 100,000 proteins as intermediaries that account
for our bodily traits, mental skills and emotional behaviours, yet we only
have about 20,000 genes. Thus genes only work in coalitions with others.
Some genes work in association with one or two of dozens, or even hundreds,
of others at any instant of time, the coalitions switching about from one
instant to the next according to the body's requirement at the time. The
lack of this very recent knowledge cost several genetics-based corporations
hundreds of millions of dollars in recent years and they had to stop their
search for the single magic bullets that could cure diabetes, heart
diseases, schizophrenia, senility, etc
Thus, the possibility of breeding for desirable traits could only be done
by the same methods as dog-, cattle- and horse-breeders. In order to
intensify a particular trait they have to carry out multiple breeding
involving multiple coalitions of the desirable gene-variations. This is
followed by the necessary culling of all those in which the right coalition
does not occur. They end up with genetic cul-de-sacs anyway. Some dog types
can't be taken any further because they've also acquired deleterious gene
coalitions. Milch-cows are probably close to their maximum potential milk
yield (that is, while still being able to stand on their own feet and carry
their udders). Race horses today are no faster than they were 70 or 80
years ago. They can't be bred further without the 'trait-gene' forming
harmful coalitions.
So, if desirable traits can't be bred in a practical way in humans (even if
we knew what they ought to be in a rapidly changing job-skills
environment), what then? Instead, we could start at the other end by
out-breed harmful genes -- more exactly harmful variations of otherwise
'standard' genes. There are two sorts of these. There are those gene
variations which are dominant. Each expresses itself in an offspring
whether the mother or the father contributes it. It can be readily
eliminated if potential parents voluntarily avoid marrying each another or,
less likely, are prepared to have their eggs and sperm fertilized
externally. In the latter case, 3 in 4 of the fertilized eggs, termed
zygotes, will have either one or two of the dominant gene-variations and
would inevitably produce the disease. Only 1 on 4 of the subsequent zygotes
are chosen -- those in which the harmful variation is totally absent and
only the non-dominant standard gene-variation from each parent is matched
up with the other.
Also there are genetic diseases in which two harmful recessive
gene-variations from the parents need to be matched up. If the mother and
father each carry such a variation then there's a 1 in 4 chance that the
variation will match up in a fertilized egg. If so, then either a disease
-- perhaps lethal -- will inevitably develop in the resultant offspring or
there will be a high propensity to a disease in certain environmental
conditions. In some countries, about 10 of these recessive possibilities
are routinely screened out from the zygotes of parents undergoing IVF
treatment. In other advanced countries it may be a many as 20. The list is
growing, however, as genetic diagnosis becomes quicker and cheaper.
Such screening of recessive diseases is not yet carried out for most
parents who are readily fertile. They have their children and take pot-luck
as to whether their harmful recessive genes match up or not. There are
hundreds, if not thousands, of potentially harmful recessive diseases in
the human population. The vast majority of them are infrequent enough in
any particular individual. Consequently, they rarely match up in parents,
though it must be said that there are many recessive propensities that are
much more common -- some herat diseases, for example -- and are being
increasingly revealed in the advanced countries because we are living longer.
However -- there's probably a commercial market already in those
intending-marrieds who strongly suspect that a particular not-so-rare
recessive disease already existed in their respective family histories.
Multiple sclerosis, a lethal disease, and acutely distressing in childhood,
is one such. In some ethnic groups (particularly in southern Europe) it can
be carried by 1 in 30 individuals, so there's a 1 in 900 chance that any
two individuals will have children in which there is a subsequent 1 in 4
chance of the two gene-variations matching up and the disease striking.
This is within range of insuring against -- were diagnosis to be widely
available and cheap enough.
Hundreds of recessive gene-variations of varying degree of frequency and
potentially harmful severity have already been identified in the human
population. In the view of geneticists there are probably thousands more
and the list is growing in research labs around the world -- if not daily,
certainly weekly. Each one of us probably has hundreds of these as single
gene-variations -- therefore not expressing their harmful effects. The vast
majority of them are so rare that most intended-marrieds who plan to have
children never think of them.
But what if DNA read-outs become cheap? The first human genomic
sequence of eight years ago cost several billion dollars. Then it became
millions and already the cost of DNA read-outs is now approaching $1,000.
In a few years' time the cost will be well within anybody's reach, at least
in the advanced countries. And, by then, the list of identifiable recessive
diseases will have grown much longer. Also, massive DNA databases will be
able to compare thousands of individual DNAs in parallel so that the
frequency of potential genetic diseases can be arrived at.
Also, because each individual carries many recessive propensities of
varying degrees of severity and frequency, some sort of genetic grading
will be possible. For each potential disease an individual, say a female,
will be a 1 or a 0. If she is a 1 and meets a male she might possibly marry
and have children with she would be able to ask him whether he is a 1 or 0
for that potential disease. If he is a 1 also, and knowing the severity of
that disease, she might not want to develop her relationship with that
male, knowing that her children will have a 1 in 4 chance of that disease.
After all, most of the other fish in the sea -- even in the case of
multiple sclerosis -- will be a 0 for that disease!
And then, being desirous of having the best quality children -- as all
mothers are, of course -- our persistent female might then proceed to the
next most serious recessive variation that she possesses. Does the possible
male have a 1 or 0 for that one? And so she could proceed steadily along
her own list of serious recessive variations. But this would involve
hundreds of comparisons!
It could, of course, be done automatically in a computer (probably in her
mobile phone in a few years' time). But this would only produce a long
list of recessive variations in which they both have a 1. She would then
have the problem of deciding whether the potential diseases (or
propensities) on the common list are severe enough or mild enough in order
to risk her children having a 1 in 4 chance of receiving it.
There is no way a male on a casual date with a female is going to put up
with this sort of procedure -- or even after a longer relationship perhaps,
when the female is beginning to become seriously interested in him as a
father to her children. But if a simpler composite grading system could be
devised, say on a 0 to 10 basis, then the genetic comparisons could take
place in the same sort of casual (?) way that a female usually finds out
what sort of job or income or family wealth a male may have. After all, she
is going to try and get the best catch she can for the sake of her children
(after, of course, all sorts of other desirable attributes she finds in him).
As a general tendency, females marry upwards -- class-wise, income-wise,
intelligence-wise. This has been shown to be so, both scientifically as
well as anecdotally. This is what Darwin realized later in his life and
what evolutionary biologists have confirmed since. In the way that females
choose upwards, this more refined mode of natural selection maintains the
genetic quality of a species. Inept or defective males remain unselected
and generally leave no children.
It is my opinion that some sort of personal genetic passport, with a
sensible and practical grading system, will be inevitable and will be
increasingly used by marriage-ready females. If the grading is, say, 0 to
10, with 10 being the highest genetic rating (that is, with the least of
the nastiest variations of high frequency) then females will, on the whole,
choose a male with a higher number than her own. That's consistent with
what females of all species of social mammals have always done in the
genetic scheme of life.
Keith
Keith Hudson, Saltford, England
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