Heedless of the risk of inept attempts at world domination, scientists at Duke University have used human DNA to create big-brained mice embryos.
The experiment is actually an attempt to understand the genetic differences between humans and chimpanzees. Our DNA is very similar, but a few small variations add up to big differences in notable places, including hairiness, poop throwing aptitude and brain size.
Through their experiment the Duke scientists tested various short bits of DNA called “enhancers.” Enhancers control the activity of genes.
The scientists compared the human versions of these enhancers to the enhancers in chimps. They found that the human version of one of the enhancers, dubbed HARE5, caused a 12 percent bigger brain when implanted into a mouse embryo than the chimp version did. That’s despite the chimp and human HARE5 being so similar that they differ by only 16 “letters” in their genetic code.
“I think we’ve just scratched the surface, in terms of what we can gain from this sort of study,” said Debra Silver, an assistant professor of molecular genetics and microbiology in the Duke University Medical School. “There are some other really compelling candidates that we found that may also lead us to a better understanding of the uniqueness of the human brain.”
This research might have practical implications because having big brains comes with a few drawbacks. Humans get brain diseases, like autism and Alzheimer’s, that chimps don’t, and studying the differences might help us better understand these ailments.
The Duke team isn’t stopping with embryos. They intend to create full-grown mice with the altered brains to attempt to study differences in brain structure and behavior.
“What we found is a piece of the genetic basis for why we have a bigger brain,” said Gregory Wray, professor of biology and director of the Duke Center for Genomic and Computational Biology “It really shows in sharp relief just how complicated those changes must have been. This is probably only one piece — a little piece.”