TUESDAY, Jan. 24, 2006 (HealthDay News) -- New genetic evidence appears to bolster the theory that humans and chimpanzees may be more closely related to one another than chimps are to gorillas and orangutans.
That's the suggestion of a study published in the Jan. 23-27 Proceedings of the National Academy of Sciences.
Researchers at the Georgia Institute of Technology concluded that the rate of human and chimpanzee molecular evolution is slower than that of gorillas and orangutans, and that humans have the slowest molecular evolution -- changes that occur over time at the genetic level.
This suggests that certain traits specific to humans -- such as generation time -- began to evolve one million years ago. In terms of evolution, that's a short period of time. Generation time, which is longer in humans, refers to the amount of time between parents and offspring. A longer generation time is closely correlated with development of a larger brain.
"For the first time, we've shown that the difference in the rate of molecular evolution between humans and chimpanzees is very small, but significant, suggesting the evolution of human-specific life history traits is very recent," biologist Soojin Yi said in a prepared statement.
"A long generation time is an important trait that separates humans from their evolutionary relatives. We used to think that apes shared one generation time, but that's not true. There's a lot more variation. In our study, we found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes," study first author Navin Elango, a graduate student in the School of Biology, said in a prepared statement.
The University of California Museum of Paleontology has more about evolution.