In a study by a researcher from University of California, San Diego, suggests that the clues of human diseases are found not in the similarity of the genome sequences between man and chimpanzee but the differences in them.
Researcher had described genetic differences between the species: one, the discovery of the first human-specific protein that is also expressed in brain cells associated with human brain diseases; the second, a single oxygen atom difference that makes humans and chimpanzees resistant to each other's malarial parasites.
This research provides examples of how studying the evolution of humans and apes from a common ancestor may yield clues to explaining human and chimpanzee diseases.
Researcher and colleagues detail their finding of the first truly human-specific protein in the September issue of Science.
Siglecs are molecules that serve as binding receptors for sialic acids, which are sugars found on the surface of all higher animal cells. Comparing human and chimpanzee genome sequences, the researchers noted that a human gene they had recently discovered called Siglec-11, was actually human-specific. The gene was generated by a mechanism called "gene conversion" that occurred in the human lineage sometime after our common ancestor with chimpanzees.
The researcher had found that while the protein encoded by the gene was expressed in human brain cells called microglia, it was not expressed in the brains of chimpanzees and other apes. By defining this human-specific genetic change, scientists may eventually better understand such neurological disorders, and possibly why humans' brains are different from those of apes.