LANGUAGE Human beings differ from chimpanzees in having complex, grammatical language. But language does not spring fully formed from the brain; it must be learned from other language-speaking human beings. This capacity to learn is written into the human brain by genes that open and close a critical window during which learning takes place. One of those genes, FoxP2, has recently been discovered on human chromosome 7 by Anthony Monaco and his colleagues at the Wellcome Trust Centre for Human Genetics in Oxford. Just having the FoxP2 gene, though, is not enough. If a child is not exposed to a lot of spoken language during the critical learning period, he or she will always struggle with speech.
LOVE Some species of rodents, such as the prairie vole, form long pair bonds with their mates, as humans do. Others, such as the montane vole, have only transitory liaisons, as do chimpanzees. The difference, according to Tom Insel and Larry Young at Emory University in Atlanta, lies in the promoter upstream of the oxytocin- and vasopressin-receptor genes. The insertion of an extra chunk of DNA text, usually about 460 letters long, into the promoter makes the animal more likely to bond with it's mate. The extra text does not create love, but perhaps it creates the possibility of falling in love after the right experience.
ANTISOCIAL BEHAVIOR It has often been suggested that childhood maltreatment can create an antisocial adult. New research by Terrie Moffit of London's Kings College on a group of 442 New Zealand men who have been followed since birth suggests that this is true only for a genetic minority. Again, the difference lies in a promoter that alters the activity of a gene. Those with high-active monoamine oxidase A genes were virtually immune to the effects of mistreatment. Those with low-active genes were much more antisocial if maltreated, yet - if anything - slightly less antisocial if not maltreated. The low-active, mistreated men were responsible for four times their share of rapes, robberies and assaults. In other words, maltreatment is not enough; you must also have the low-active gene. And it is not enough to have the low-active gene; you must also be maltreated.
HOMOSEXUALITY Ray Blanchard at the University of Toronto has found that gay men are more likely than either lesbians or heterosexual men to have older brothers (but not older sisters). He has since confirmed this observation in 14 samples from many places. Something about occupying a womb that has held other boys occasionally results in reduced birth weight, a larger placenta and a greater probability of homosexuality. That something, Blanchard suspects, is an immune reaction from the mother, primed by the first male fetus, that grows stronger with each male pregnancy. Perhaps the immune response affects the expression of key genes during brain development in a way that boosts a boy's attraction to his own sex. Such an explanation would not hold true for all gay men, but it might provide important clues into the origins of both homosexuality and heterosexuality.
Also, in the back of the magazine, a little Q&A with Joey Fatone.
'N Sync crooner Joey Fatone hosts Fame, an American Idol-esque talent search that starts this week on NBC:
Level with us: Clay or Ruben? I'm actually a Clay guy, believe it or not. Ruben has an amazing voice, but he's kind of like your typical Luther Vandross or Peabo Bryson. Where Clay is - I've never seen anybody like that, except for maybe Rick Astley, way back when. He's this little guy with this tremendous voice.
Have you actually seen the movie Fame? Oh, yeah! That's like the bible for me.
So what exactly is your role on the show? I'm like the Ryan Seacrest, I guess. [Laughs] I'm just gonna be myself. And hopefully not act like an idiot.
Are you going to sing? Hell no! I'll be hosting. I don't know exactly what that consists of, but I'll be hosting.
Gotcha. We'll be watching. Let me know if I suck, all right?