Generalist genes ’cause all learning disabilities’

Here’s what I know about the illusive, mysterious, “gene” theory:

We CAN determine “physical” characteristics thru chromosomes (i.e.
male/female, down syndrome).

We CANNOT “demonstrate”, in human beings, how a sequence of nucleotides
(codons) is tied to a specific behavior or to the idea that a
subject/concept (i.e. MATH, LANGUAGE) cannot be taught to a child.

During a legal battle I was involved in, some self-proclaimed ADD experts
tried to pull this nonsense on me. When I asked them to provide me
with the “sequence of nucleotides” that make up the ADD gene.

Guess what?

no such thing.

Nestor

    Generalist genes 'cause all learning disabilities' 

    10:31 10 September 03

    NewScientist.com news service

    Learning disabilities result from general problems in the brain rather
than specific genetic or neurological defects, the British Association
Festival of Science in Salford was told on Tuesday.

    A large but unidentified group of genes, each with very small effects on
overall brain function, work together to determine most of mental ability,
says Robert Plomin, at the Institute of Psychiatry in London.

    If Plomin's theory proves correct, common learning disabilities such as
dyslexia will need a dramatic redefinition. Dyslexia is commonly defined as
a reading problem in someone who has otherwise normal intelligence.

    In fact, Plomin disputes the idea of learning disabilities at all,
saying instead that these people simply fall at the lower end of the
spectrum of cognitive ability.

    Plomin's theory is likely to be controversial and to be met with
scepticism by the education and research communities. Christine Temple, a
researcher at the University of Essex who presented her own research on
specific memory problems in childhood, says: "There are clearly children
with normal mental function and very specific disabilities. This is what we
see clinically."

    Maths and reading

    Plomin studied 15,000 sets of twins as they grew up. At seven years old,
researchers compared rates of learning disabilities in pairs of identical
and fraternal twins.

    They found that identical twins were more likely to be afflicted with
the same disorder than were fraternal twins, confirming a genetic root for
learning disabilities. But researchers also checked if a child with a
problem in maths was likely to have a twin with a reading disability, and
vice versa. They found the link was more common in identical than fraternal
twins.

    In fact, genes that affect reading have a 70 per cent chance of also
affecting maths ability. "Genes are generalists - the same genes affect all
disabilities," concludes Plomin.

    "People look for a hole in the brain that causes a problem, but I think
the brain evolved to work together to solve a problem," he told New
Scientist. Any specific differences in learning ability are probably due to
environmental effects, he says.

    At this point, the implications for children with learning problems,
specific or not, are unclear. Scientists do not know which genes, or even
how many genes, are involved. Some candidate genes may be those involved in
general brain processes such as synaptic plasticity, Plomin says.

    Furthermore, the individual effect of each gene involves is likely to be
so small - accounting for less than one per cent of the variation in general
cognitive ability - that studies attempting to find them will have to
analyse huge numbers of people.

    Emily Singer, Salford