After almost a decade of research, Yale scientists in partnership with scientists from Howard University have published a new genetic analysis tool that may soon change the way we differentiate between humans and chimpanzees, our close genetic relatives.

Published in July, the paper describes a computational model, model averaged site selection via Poisson random field, or MASS-PRF, that at the basic level looks at small regions of our genes and determines the likelihood that the sequence of the area will change.

Co-authors Jeffrey Townsend, a professor of biostatistics at the Yale School of Public Health, and Michael Campbell, a biology professor at Howard University, have been working on the model since 2009, according to Townsend. Their model represents a breakthrough in that it considers small portions of genes rather than whole genes, distinguishing it from existing approaches.

“Suddenly we have a telescope that can go 10 times as far,” Townsend said. “Anytime you find a small difference, it teaches you not just that something’s changed, but about the biology of that gene.”

Townsend’s lab tested 58 genes common to chimps and humans, and found that certain genes involved in memory, fighting disease and reproduction were apt to change.

Zi-Ming Zhao, lead author of the paper, said that the researchers’ results indicate that even though the same list of genes could be shared by human and chimps, important novel functions of these genes might be only seen in humans. She added that Campbell’s lab at Howard University is currently working to clarify these differences using MASS-PRF.

Deciphering the differences between humans and chimps has a value beyond satisfying human curiosity, however. There are important practical applications, including animal testing, that this data can be used for.

“Understanding the evolved differences is very important, so that, say that we are developing a treatment for Parkinson’s and it’s being tested in chimpanzees, what we need to know is if the gene we’re targeting is functioning in the same way,” Townsend said.

Current research with the model includes studying species of rice to decipher the differences in genes and their functions. Genetic engineers can later use this data to create more efficiently producing rice, Zhao said.

She added that further studies of such functionally important genes in domesticated rice might have great economic benefits and help solve the poverty issues around the world.

In the future, MASS-PRF can be used to help treat cancer patients, according to the researchers. The model can help clarify which cancer genes are more likely to change, and in turn dictate what drugs to use on tumors.

“You can understand which genes are being selected for in cancer and target your research in response to that,” said lab member Daniel Lee ’16. “The real story for the model will arise when we see people apply it.”

Over 200 cancer drugs are available in the United States, according to the National Institutes of Health.

Anusha Manglik |