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Gene may affect IQ in males, scientists say

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posted on Dec, 2 2005 @ 10:08 PM

Gene may affect IQ in males, scientists say

Scientists in North Carolina say they have identified a gene that affects IQ, a finding that, if confirmed, would be a significant step toward understanding the genetic basis for intelligence.

The new research could also have ethical implications because the effect of the gene appears to be quite dramatic: The scientists say that males who inherit a particular version of the gene have, on average, an IQ that is 20 points lower than males who don't.

"I have to admit, the ramifications of it are great," said Randy Jirtle, the Duke University biologist who led the new research, noting that current genetic testing techniques can easily determine which males have the gene version and which ones do not.

However, he stressed that the IQ results in his research were based on a group average; individual males carrying the gene version had a wide range of IQ scores. While females also can carry the gene variation, it does not appear to affect their IQ, he said.

Dr. Jirtle reported the new findings last month at a scientific conference in Durham, N.C...

Dr. Jirtle's research centers on a gene identified by the abbreviation IGF2R, for type 2 insulin-like growth factor receptor. The gene governs the production of a protein that, among other jobs, affects cell growth. All people carry the gene, but some have a version with a slightly different code, or variation, Dr. Jirtle said. This gene variation, he and his colleagues found, correlates with a lower IQ.

The researchers studied about 300 children with an average age of 10. The children, all Caucasian, came from six counties in the Cleveland area. As a group, males – but not females – who had the variant gene had IQ scores about 20 points lower than males who didn't.

Dr. Jirtle cautioned that inheriting the different version of the gene did not guarantee a lower IQ. Although as a group, average IQ scores were lower, but there were still males who had the variant gene and a higher IQ. (Two boys with the variant version of the gene had very high IQs of 160, Dr. Jirtle said.) And males with the more common form of the gene can also have a lower IQ.

Dr. Jirtle said his assertion that the IGF2R gene affects IQ is bolstered by experiments in mice. When he and his colleagues disabled a copy of the gene in lab mice – an experiment intended to mimic humans who inherit the variant copy of the gene – they noticed that the male mice were slow learners on a maze test. Electrical recordings of the mice's brain tissue were also altered in a way that is consistent with slow learning.


Another double edged discovery....

One could really paint a bleak picture for humanity with relative ease...

Hope I'm wrong.

posted on Dec, 2 2005 @ 10:46 PM
Though this discovery may be of some relative importance, it is already a known 'given' in psychology and developmental sciences [human development] circles. Some research reports indicate that there are indeed genetic differences in individuals. Do genes entirely dictate an individuals overall intelligence? I would hazard an opinion and say 'no,' not entirely.

Having said that, even if intelligence has a genetic factor, intelligence is not solely determined nor dictated by genetic factors. Environment (home, etc) plays a big role as evident by Klineberg's proposed a cumulative-deficit hypothesis to explain that impoverished environments inhibit intelligence growth, and these negative effects accumulate over time. Environment stimulates intellectual growth or inhibits it, but the most important factors are parental involvement with the child or children and opportunities intellectual stimulation. Social class, nutrition, education, living conditions, etc also effect intelligence, also negatively or positively.

So, even though genes partially explain individual intelligence differences, differences in environments ultimately determine overall intelligence.

Bear in mind that on average, during the 20th century, IQ scores have increased in all countries, and in the US, the increase has amounted to 3 to 4 IQ points per decade, per a research done by James Flynn. The phenomenon is called the Flynn effect. As such, would this phenomenon be more attributed to genes and genetics or environment?


[edit on 2-12-2005 by Seekerof]

posted on Dec, 2 2005 @ 11:02 PM
IQ is an important measure, but it is only one factor in the all the factors that contribute to living a good, satisfying life. It would be nice if someone could find a motivation gene. This is an important finding, but as the article notes, the real difference is in the individuals. Very many intelligent people live lousy, unfulfilling lives and very many ordinary folk accomplish very extraordinary things.

posted on Dec, 2 2005 @ 11:38 PM

Originally posted by GradyPhilpott
Very many intelligent people live lousy, unfulfilling lives and very many ordinary folk accomplish very extraordinary things.

Agreed....and therein lies the danger. Too many would jump at the chance to tamper with this in an effort to bank on that statement being wrong for the intelligent guys...

posted on Dec, 3 2005 @ 01:49 PM
In taking a past graduate level Developmental Psychology class, in doing some research, I had saved to disc a couple of notable links, one being an interesting APA Journal article discussing genetic heritability and environmental effects:
Heritability Estimates Versus Large Environmental Effects: The IQ Paradox Resolved

A better explanation for the Flynn Effect with graphics:
The Flynn Effect

This interesting article:
Male Versus Female Intelligence: Does Gender Matter?


Many studies consistently show that the average IQ scores of men and women are equivalent. Although most of the common tests, such as the Wechsler Adult Intelligence Scale (WAIS), are intentionally designed to weed out a sex bias, some gender-specific findings persist.

Men tend to perform better on spatial questions.
Women outpace men on reading and other verbal skills.

Men score more at the extremes of IQ scoring—both high and low. More men than women test at the lower end of the IQ scale, and also at the very top. This is consistent with the membership of American Mensa, Ltd, a society whose members test in the top 2% of the population on a standard IQ test. The group reports that 65% of its general membership is male, and 35% female. Yet the Association for Women in Mathematics claims that women earn half of all undergraduate mathematics degrees and one-third of PhD degrees in math.

Similarly, men consistently outscore women by an average of 35 points on the math portion of the college SAT test. Interestingly, some studies show that boys and girls test about the same in math in elementary school. The girls fall behind only later in life, so that by the time senior year in high school arrives, the boys test higher on the SAT. Researchers continue to study whether these findings—and those like it—are the result of gender differences, environmental influences, social pressures, personal beliefs and values, or a combination of all and more.

One further journal article dealing with genetics, race, environment, and overall intelligence in male and females:
Intelligence, Race, and Genetics

In the above article, it is mentioned that no gene has yet been conclusively
linked to intelligence.


[edit on 3-12-2005 by Seekerof]

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