"These results show that the rapid behavioral responses to social opportunity were matched by a rapid genomic response in the brain," Fernald says. "We didn't expect to get changes in gene expression in the brain so early in the process, just 20 minutes after the male has seen the prospect for social change."
These results suggest that subordinate males are always looking for opportunities to change, Burmeister adds. "They must constantly be ready, because they make the shift in no time," she says. "They keep track of who's who and who's the biggest so they can take the opportunity to reproduce. An animal that goes through that kind of transition has to recall how he relates to other males, and also has to be aware that he can change. This raises a bigger question about sophisticated social awareness in fish. After all, socialization requires more brainpower, and all vertebrates--fish, amphibians, birds, humans--use a variety of cues in the environment."
The difficult question that remains, according to Fernald, is to figure out exactly how social information can trigger a genetic response that results in such a profound change in an animal's appearance and behavior.
"All we did was to change his social status, and yet it's reading from his brain right down to his gonads in a way that has to have a cellular and molecular underpinning," Fernald says. "In other vertebrates, it's the same process. Human males go through puberty, although it's not reversible, of course. However, we are social animals, and we respond to social situations. We may be seeing in cichlids the e