IQ-Gene

In the angry debateover how much of IQ comes from the genes that children inherit from parents andhow much comes from experiences,one little fact gets overlookeD.no

one has identifiedany genes(other than those that cause retardation)that affect intelligence.Soresearchers led by Robert Plomin of London's Institute of Psychiatry decided to

look for some.Theyfigured that if you want to find a"smart gene",you should look insmart kids.They therefore examined the DNA of students like those who are sobright

that they take collegeentrance exams four years early一and still score at Princeton-caliber levels.The scientists foundwhat they sought."We have,"says Plomin, "the first

specific gene everassociated with general intelligence."

Plomin's colleaguesdrew blood from two groups of 51 children each,all 6 to 15 years old and livingin six countries around Cleveland.In one group,the average IQ is 103.All

the children arewhite.Isolating the blood cells,the researchers then examined each child'schromosome 6.Of the 37 land marks on chromosome 6 that the researchers looked

for,one jumped out:aform of gene called IGF2R occurred in twice as many children in the high-IQgroup as in the average group—32 percent versus 16 percent.The study,in

the May issue of thejournal Psychological Science concludes that it is this form of the IGF2R genethat contributes to intelligence.

Some geneticists seemajor problems with the IQ-gene study.One is the possibility that Plomin'sgroup fell for"chopsticks fallacy".Geneticists might think they'vefound a

gene for chopsticksflexibility,but all they've really found is a gene more common in Asiansthan,say,Africans. Similarly, Plomin's IQ gene might simply be one that is more

common in groupsthat emphasize academic achievement."What is the gene that they've foundreflects ethnicity?"asks geneticist Andrew Feinberg of Johns Hopkins

University."Thatalone might explain the link to intelligence,since IQ tests are known for beingculturally sensitive and affected by a child's environment."And Neil Rischof

Standford University points out that if you look for 37 genes onchromosome,as the researchers did, and find that one is more common in smarterkids,that might reflect pure

chance rather than acausal link between the gene and intelligence.Warns Feinberg:"I would takethese findings with a whole box of salt."What does Feinbergmean by saying"I would take these findings with a whole box of salt"?

A.He would considerthem while eating his meals.

B.He definitelybelieves the findings.

C.He would considerthem while shopping for salt.

D.He doubts thefindings very much.