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Predict eye color with DNA sample?

Citizen Staff Writer



The connection between diabetes and eye color is not so far fetched.

A team of researchers at the University of Arizona is trying to find a few specific changes in a person’s DNA blueprint that will explain the majority of variation in hair, skin and eye color.

These blueprints, or genes, are letters that describe their individuality. The blueprints can tell us a person’s likelihood of developing heart disease, diabetes and cancer, for instance.

The human genome has about 4 billion nucleotides. These nucleotides are the pieces that make up a person’s genetics.

Murray Brilliant, a professor in the College of Medicine, leads the team of researchers. The team looked at the blueprints of 1,000 UA students. Participants were given $20 for participating in the research.

Brilliant compared them to the students’ genetic traits such as their hair, skin and eye color.

“In essence this is a model of complex genetic traits,” Brilliant said. “It has implications for forensic studies where now we can take DNA from an individual we’ve never seen and make predictions based on these models as to what that person’s pigmentation might be.”

The model was developed by Robert Valenzuela, a fourth year genetics graduate student. It is a statistical model that determines the three best single-nucleotide polymorphisms to explain the variation in humans. A single-nucleotide polymorphism is a genetic variation in a DNA sequence that occurs when a single nucleotide in a genome is altered.

This model will allow forensic scientists to better determine what a person looks like through a DNA sample. Brilliant says the model, for example, could determine with about 70 percent certainty that a person has blue eyes just from a DNA sample left at the crime scene.

Valenzuela received his bachelor’s degree in physics from Arizona State University.

He received a master’s in biology at Northern Arizona University. He also has worked for the United States Geologic Survey.

He wanted to come back to school to utilize the tools he had learned as a graduate student at NAU.

“I like the aspects that the U of A is introducing, meaning that not only do we take courses in genetics, but also molecular and cellular biology, ecology and evolutionary biology courses,” Valenzuela said. “It makes us better researchers because we can have an idea of what’s occurring in these other fields.”

An article on the UA research is set to run in the Journal of Forensic Science, but Brilliant said he did not know when it would appear.

UA research may lead to advances in forensic work

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