Macaque monkeys join the genome club
Two years ago, scientists announced the completion of the chimpanzee genome and stunned the public opinion by showing that chimp’s DNA is 98% identical to ours. Being able to compare the human genome sequence with that of our closest living relative was very useful, but many questions can not be properly addressed without having a third reference point, and there is where the macaque comes handy.
A recent article in the journal Science presents the DNA sequence of the rhesus macaque, a species of monkey that lives throughout the Asian continent. Old-world monkeys like the macaque are thought to have diverged from the primate line that led to humans about 25 million years ago. In spite of the time separation, the study of the new sequence reveals that we are still 93% identical in our DNA.
Captive-bred macaques are often used as a model in testing experimental drugs and medical treatments. Knowing the sequence of the macaque genome is important to understand how they differ from us, and that should help to better predict the effects that a given drug that was tested on macaques will have on humans.
Studying the macaque sequence is also exciting for biologists because it should help them learn more about what makes us humans. Scientists compare the DNA of the three species (human, chipm and macaque), and when, for example, they find a DNA difference between humans and chimps, they can check it against the macaque sequence to figure out whether the chimp or the human carries the more ancient version of the DNA.
Such comparisons help scientists to discover regions of the genome that contributed to the evolution of humans. This method will become even better over the next few years since other non-human primate genomes are already being sequenced. Gibbon, marmoset, orangutan and the gorilla are next in the row.
