Scientists studying the difference between human and chimpanzee DNA have found one stretch of human DNA that can make the brains of mice grow significantly bigger.
"It's likely to be one of many DNA regions that's critical for controlling how the human brain develops," says Debra Silver, a neurobiologist at Duke University Medical School.
The human version of a DNA sequence called HARE5 (inserted into this mouse embryo) turned on a gene that's important for brain development. (Gene activity is stained blue.) By the end of gestation, the embryo's brain was 12 percent larger than the brain of an embryo injected with the chimpanzee version of HARE5.
It could also help explain why human brains are so much bigger than chimp brains, says Silver, who notes that "there are estimates of anywhere from two to four times as big."
In addition to having bigger brains, Silver says, humans also "have more neurons, and we have more connections between these neurons."
Scientists would like to understand what the genetic basis is for humans' apparently special capacity for logic, abstract thought, complex emotions and language. Humans and chimpanzees have DNA that's remarkably similar — researchers say our genetic code is about 95 percent identical. But Silver and some colleagues recently started looking at pieces of DNA that differ markedly between chimps and humans. - Health News : NPR
'Big Brain' Gene Found in Humans, Not Chimps : Discovery News
A single gene may have paved the way for the rise of human intelligence by dramatically increasing the number of brain cells found in a key brain region. This gene seems to be uniquely human: It is found in modern-day humans, Neanderthals and another branch of extinct humans called Denisovans, but not in chimpanzees. By allowing the brain region called the neocortex to contain many more neurons, the tiny snippet of DNA may have laid the foundation for the human brain's massive expansion.Hidden gene gives hope for improving brain function -- ScienceDaily
The gene is a long, noncoding RNA and was found within a section of the genome most commonly associated with "junk" DNA -- the 98 per cent of the human genome that, until recently, was thought to have no function. This is the first time long, noncoding RNA activity has been detected in the brain in response to experience "Early biologists thought that DNA sequences that do not make protein were remnants of our evolutionary history, but the fact is these sequences are actually highly dynamic and exert a profound influence on us," Bredy said.
'Big Brain' Gene Found in Humans, Not Chimps - Yahoo News
A single gene may have paved the way for the rise of human intelligence by dramatically increasing the number of brain cells found in a key brain region.This gene seems to be uniquely human: It is found in modern-day humans, Neanderthals and another branch of extinct humans called Denisovans, but not in chimpanzees.By allowing the brain region called the neocortex to contain many more neurons, the tiny snippet of DNA may have laid the foundation for the human brain's massive expansion."It is so cool that one tiny gene alone may suffice to affect the phenotype of the stem cells, which contributed the most to the expansion of the neocortex," said study lead author Marta Florio, a doctoral candidate in molecular and cellular biology and genetics at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany. Still, it's likely this gene is just one of many genetic changes that make human cognition special, Florio said. [The Top 10 Things That Make Humans Special]