How do genes relate to who we are?
Notes on a talk by Dr Matt Ridley - author of Genome
9th June 2001, The Newcastle University Convocation Public Lecture.
Craig Venter, head of Ventromics, on the eve of the publishing of the human genome said that 30,000 genes were too few to explain human behaviour, and that therefore we are free after all.
Dr. Ridley says that there are two weaknesses in this argument,
is the assumption that more genes is equal to more complexity and more control.
is the assumption that control by the environment is freedom. e.g. if my upbringing predisposes me to depression, I can no less change than if it were "written" in my genes.
The whole problem with this approach is the assumption that DNA is a blueprint. This is perhaps the wrong model or analogy. Perhaps we should consider that our genes are a recipe for a human being. (A blueprint for a cake requires that I determine where each current and raisin will be in the final product, a recipe only requires that I add a certain approximate amount to the mixture.)
There genes that code for differences and similarities.
The Huntingdon gene and CAG repeats. This is not an unwanted gene. it is necessary. but variations in the length of CAG repeats over 35 induce Huntingdon's disease. The unusual scenario is that the length can very accurately predict the age at which the onset occurs.
ACE genes and athleticism. on Chromosome 17 there are two varieties of the ACE gene one has extra repetitions, and the extra length is associated with physical attributes and stamina that enhance athletic performance. In fact only those with the long gene can reach top of Everest without additional oxygen.
D4DR and adventurousness. The longer the gene the more adventurous the person, but Dene Haimer, who did the work, was quick to point out that a 5% is was only a contributory factor.
There are also genes that contribute to aptitudes for music and intelligence.
There are some genes that do not vary, and therefore code for similarities between human beings.
the Y chromosome codes for similarity between men
all life use the same code, therefore all descended from one creature/organism
all segmented animals use the same Hox gene.
all African apes have 32 teeth.
all humans have five fingers, a shared attribute with apes.
all human beings smile and frown, and that is irrespective of culture, and may therefore have a genetic combination contributing the ability.
Genes don't constrain, they enable.
Nature is not the opposite of nurture
Nature and nurture complement one another. A baby ape is not afraid of snakes. When it sees another ape showing fear, it learns very quickly. But you cannot teach the baby ape similarly to be afraid of flowers. There may therefore be good genetic preparation for certain kinds of learning.
The genetic predisposition may make it easier to do certain kinds of things, but what controls our learning and development is our appetite for certain things.
William James said, human beings have more instincts not fewer.
Language for human beings is an instinct. It is unique to the realm of living things except for perhaps the bottle nosed dolphin which possibly also has a language.
Human nature is like a cake baked to a genetic recipe by experience.
The Paradox of Fate
Nurture is still determinism: e.g. autism; and If prone to depression by bad parenting it is equally unchangeable by the sufferer.
Nurture is not necessarily reversible e.g. accent becomes relatively fixed at a certain age.
Nature is not necessarily irreversible. e.g. PKU the effects of this genetic condition can be avoided by avoiding Phenylalanine in the diet; and dyslexia - innate condition, remedial by educational processes
meritocracy depends on nature. If people should be able to achieve because of their abilities this depends upon their genetic inheritance. If only the socially advantaged should succeed then that's an argument for nurture.
Fatalism is sometimes welcome.
Genes are cogs not Gods
Hume's fork & Spinoza's stone
Hume's fork - he suggested that all are actions are either determined or random, in which case we are not in control, and there is no free will.
Spinoza's stone - a human being is like a stone rolling down a hill, the only difference is that the stone doesn't have the illusion that it is in control.
Genes are consequences as well as causes.
17 genes are necessary for learning and development. these were discovered in fruit flies. An experiment showed that fruit flies could learn and remember. (Experimenters passed an electric current through a grid on which the flies were standing causes them to fly off. Just prior to the jolt a chemical smell was introduced into the container. The flies eventually learned to avoid the shock by flying when the smell came.)
The same 17 genes are responsible for memory and intelligence in mice. Experimenters have learned how to increase the activity of these genes, and that has been shown in increased speed of solving maze puzzles. However we do not know what is going on in the mind of the mouse. There is no extrapolation to the effects of increasing the activity of the same 17 genes that are responsible for learning and memory within human beings.
These genes are at our mercy, they carry out the instructions to lay down memory within the brain.
AJP - this process implies genetic therapy for memory loss, treatment for altzheimer's, and the possibility of pills to make academics.
We can turn on genes, but cannot accurately put invented genes into the genome.
A question and answer session followed.
This is a page from
genefaith.org compiled by Andrew J. Palmer
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This page had minor updates 13th October 2003.