Researchers discover genes that distinguish human, nonhuman primate brains

A research team from the Salk Institute, the Yerkes National Primate Research Center of Emory University, and the University of California, Los Angeles (UCLA), has identified genes in the cerebral cortex that differ in levels of activity between humans and nonhuman primates, including chimpanzees and rhesus monkeys.

These findings, which appear in the Proceedings of the National Academy of Sciences (October 28, 2003; 100(22):13030-5), may provide essential clues to the unusual cognitive abilities of humans. They also may help researchers understand why humans have a longer lifespan than other primate species and yet are so vulnerable to age-related, neurodegenerative diseases.

Because the DNA sequences of humans are so similar to those of chimpanzees, scientists have long speculated that differences in the activity levels of particular genes, otherwise known as gene expression, and, as a result, the amounts of particular proteins cells produce, are what distinguish humans from chimpanzees. The recent sequencing of the human genome has led to the development of "gene chips" that enable researches to examine the expression levels of thousands of genes at a time as well as compare expression levels in different species.

Using gene chips to compare samples of the cerebral cortex of humans, chimpanzees and rhesus monkeys, the research team at the Salk, the Yerkes Center, and UCLA identified 91 genes that are expressed in different amounts in humans compared to the other primate species. Upon further study, the team observed 83 of these genes showed higher levels of activity in humans, and as a result, regulated neural activity.

Posted by Tom on November 13, 2003