General intelligence is a heritable trait that is a risk factor for both the onset of dementia and the rate of cognitive decline in community-dwelling older persons. Previous studies screening for quantitative trait loci (QTLs) that influence general intelligence in healthy individuals have identified four loci, two of which are located within the genes insulin-like growth factor 2 receptor (IGF2R) and the Msx1 homeobox. Here, the authors report the finding of another QTL associated with general intelligence that is located within exon 2 of the cathepsin D (CTSD) gene. A group of 767 healthy adults with a follow-up period of over 15 years have been analyzed for cross-sectional and longitudinal trends in cognitive change using the Heim intelligence test score (AH4-1). The authors observed a significant association (P=0.01) between a functional C>T (Ala>Val) transition within exon 2 of the CTSD gene that increases the secretion of pro-CTSD from the cell, and the AH4-1 score at initial testing on entry to the longitudinal study. Interestingly, CTSD is transported by IGF2R from the trans Golgi network to the lysosome.
Citation source: Molecular Psychiatry 2003 Volume 8, number 1, pages 14-18.
and
http://www.apa.org/monitor/feb03/breaking.html
http://www.volkmar-weiss.de/majgenes-full.html#poly
these aren't the mainstream fodder that was presented previously,
hope those are reputable enough for you.
Heh, those of their ilk... I just like that line.
I admit, that my language wasn't what could be called "neutral",
but I was overcome with angst and disgust after another conversation
elsewhere on the same subject.
" IQ testing is a qualitative tool at best. IQ tests are good for testing a person’s ability to perform IQ tests, and not much more. “Intelligence” is a very difficult thing to quantify"
I find it amazing that given the degree in which IQ correlates with success and achievment that its still poo-pooed as non-consequential and only a measure of
ones ability to take tests.
And yessssss, I suppose that a lack of essential nutrients (iodine) or
a lack of emotional/mental stimuli would have an effect on IQ,
but only in a detracting manner,
There isn't (to my knowledge) an environmental factor
that can raise you above what your genes allow for.
example:
The genes you were born with give you a potential for having
a 130 IQ, a steady diet of television, a lack of breastmilk as an infant,
or a lack in dietary necessities might depress the IQ to 100,
but theres not enough books in the library or enough concerned teachers
that would raise your IQ to 160; its not in your genetic makeup.