ITHACA, N.Y., Dec. 20 (UPI) -- A gene-comparison project at Cornell University in Ithaca, N.Y., found "lifestyle" changes may account for the difference between chimps and humans.
The study, published in the journal Science, suggests although nearly 99 percent of the genetic makeup of chimps and humans is the same, changes 6 million years ago in how humans perceive odors and what they eat may account for the differences.
Science Daily Magazine said the comprehensive comparison of the genetic differences between two primates indicated evidence of positive selection in genes involved in olfaction, or the ability to sense and process information about odors.
The researchers said they found hundreds of genes displaying a pattern of sequence change that is consistent with adaptive evolution. The changes in our human ancestors involved their sense of smell, digestion, long-bone growth, hairiness and hearing.
Evolutionary geneticist Andrew Clark, a Cornell professor of molecular biology and genetics, told Science Daily: "It is a treasure-trove of ideas to test by more careful comparison of human and chimpanzee development and physiology. The analysis generates many hypotheses that can be tested to yield insight into exactly why only 1 percent in DNA sequence difference makes us such different beasts."
