The findings of a recent study may facilitate future research on genetic diseases, while saving the lives of monkeys.

Members of Penn State faculty collaborated with researchers nationwide to analyze and develop the genome sequence -- a map of DNA structure that identifies functions of certain genes -- of the rhesus macaque monkey, said Webb Miller, researcher and professor of biology and computer science and engineering at Penn State.

Analysis of the sequence determined that the monkey's genome is about 93 percent similar to the human genome, Miller said.

The monkey is currently the main clinical model for studying human disease. The analysis of its genome sequence allows researchers to more easily identify diseases to which the monkey and humans respond similarly. This is done so researchers can avoid subjecting a monkey to research if it would not lead to a better understanding of a certain human disease, Miller said.

"Our goal is to make [medical research] much more effective
rather than just guessing which monkey will be efficient as a model for some disease progression -- we would like to know ahead of time," Miller said. "It would save a lot of monkeys."

Because mutations, changes in DNA, are the cause of genetic disease in humans, the genomic similarity between humans and monkeys can be used to identify certain sequences that are considered mutations in humans but are considered normal in monkeys, Miller said. By looking at mutations in the human genome, researchers are able to determine what regions of the genome have undergone change and identify these areas as locations where evolution is happening, he said.

"We looked at a collection of human mutations that are associated with disease and looked at the corresponding sequences in [monkeys] and found a few hundred instances where the human mutations are actually normal in [monkeys]," said Ross Hardison, researcher and professor of biochemistry and molecular biology at Penn State.

Researchers observed evidence of evolution when looking at changes in the human genome that can cause genetic disease and comparing them to corresponding sequences in the monkey genome that are considered normal and do not result in disease, Miller said.

Analysis of the monkey genome suggests that the monkey's lifestyle is more similar to that of humans' ancestors and that mutations in the human genome are likely the results of the current human lifestyle, Hardison said.

Researchers believe that humans' ancestors consumed very few calories and were much more active than current humans, Hardison said.

"I think [the research] provides a whole new avenue to better understand how some of these gene changes can be associated with disease, but I think it's really the beginning of more studies," Hardison said.

By studying the mutation rates of sex-determining chromosomes in the monkeys and humans, Kateryna Makova, assistant professor of biology at Penn State, found that more mutations originate in males than in females because males undergo more cell divisions, Makova said. This also puts men at a greater risk of genetic disease, she said.