单选题
In the angry debate over how much of IQ comes from the genes that children inherit from parents and how much comes from experiences, one little fact gets overlooked: no one has identified any genes (other than those that cause retardation) that affect intelligence. So researchers led by Robert Plomin of London"s Institute of Psychiatry decided to look for some. They figured that if you want to find a "smart gene", you should look in smart kids. They therefore examined the DNA of students like those who are so bright that they take college entrance exams four years early—and still score at Princeton-caliber levels. The scientists found what they sought. "We have," says Plomin, "the first specific gene ever associated with general intelligence."
Plomin"s colleagues drew blood from two groups of 51 children each, all 6 to 15 years old and living in six counties around Cleveland. In one group, the average IQ is 103. All the children are white. Isolating the blood cells, the researchers then examined each child"s chromosome 6. Of the 37 landmarks on chromosome 6 that the researchers looked for, one jumped out: a form of gene called IGF2R occurred in twice as many children in the high-IQ group as in the average group—32 percent versus 16 percent. The study, in the May issue of the journal Psychological Science , concludes that it is this form of the IGF2R gene that contributes to intelligence.
Some geneticists see major problems with the IQ-gene study. One is the possibility that Plomin"s group fell for "chopsticks fallacy". Geneticists might think they"ve found a gene for chopsticks flexibility, but all they"ve really found is a gene more common in Asians than, say, Africans. Similarly, Plomin"s IQ gene might simply be one that is more common in groups that emphasize academic achievement. "What is the gene that they"ve found reflects ethnicity?" asks geneticist Andrew Feinberg of Johns Hopkins University. "That alone might explain the link to intelligence, since IQ tests are known for being culturally sensitive and affected by a child"s environment." And Neil Risch of Standford University points out that if you look for 37 genes on a chromosome, as the researchers did, and find that one is more common in smarter kids, that might reflect pure chance rather than a causal link between the gene and intelligence. Warns Feinberg: "I would take these findings with a whole box of salt."

单选题 In the beginning of Paragraph 1 we are told that scientists can not agree ______.

单选题 What does "some" in the second sentence of Paragraph 1 stand for?

单选题 A gene for chopsticks flexibility is found to be ______.

单选题 Plomin"s IQ-gene study is similar to the chopsticks gene finding in that ______.

单选题 What does Feinberg mean by saying "I would take these findings with a whole box of salt"?