Mutation in the Middle
Webbed fingers, brittle bones, dramatic premature aging, lack of irises, and spontaneous bruising all sound like stuff from a science fiction novel, but these real quirks of nature can come from minute mutations in our DNA. With over 3 billion letters making up our DNA, there is a lot of room for errors. Fortunately, Dr. Val Sheffield (BS ’74, MS ‘77), has plenty of experience sorting through DNA. As a geneticist, professor, doctor, and researcher, he works to identify where disease mutations occur and how to help patients who suffer from these diseases.
Sheffield’s calling in life began in Biology 100 at BYU. He recalls: “As Dr. Barnes described Gregor Mendel’s experiments with pea plants, I was fascinated . . . particularly that Gregor Mendel’s principles would apply to human heredity and not just plant heredity.” Inspired by Mendel, Sheffield finished two degrees at BYU and then earned an MD and a PhD from University of Chicago.
Later, his laboratory at the University of Iowa would help in mapping the entire human genome, an enormous undertaking. Containing over 20,000 individual genes, the human genome is kind of like our body’s blueprint, determining everything from the shape of your hairline to your dimples to whether you are apt to contract breast cancer. Because genes vary from person to person, the human genome never stays exactly the same. For this reason, it’s helpful to study genetics in families where genes between parents and children are similar. Sheffield explains, “My collaborators and I decided that if we studied certain genetic disorders that were being inherited within families, we would be able to identify specific regions in the genome that were involved in the given disease.” Undeterred by the sheer number of genes, Sheffield and his collaborators began their research.
“[We] decided to work on identifying genetic markers, or pieces of DNA that differed between individuals. When we studied certain genetic disorders that were being inherited between families, we could then identify specific regions in the genome that were involved in the given disease. . . . We could also identify the disease gene and the genetic mutation that was causing the given disease. Of course, the true help we want to give is to treat the disease…In order to treat it, however, it’s very valuable to know the gene that’s causing it.”
Sheffield’s recent work includes studying hereditary blindness and genetic mutations among families in southern Israel. While studying the families, Sheffield and his team discovered a rare syndrome, Bardet-Biedl Syndrome. Sheffield explains, “The patients would go blind. . . but they also had other things wrong with them, such as being overweight. By studying this rare disorder, we were able to identify several genes that were involved in both blindness and in obesity. . . .” This led to more questions, tests, and discoveries. “There’s actually a whole bunch of genes that are involved,” Sheffield says. “It’s actually up to 21 different genes that can independently cause this particular disorder when the gene is mutated.”
With so many variables involved in Bardet-Biedl Syndrome and other genetic disorders, Sheffield has his work cut out for him. The scale of the research is daunting; however, Sheffield reports, “It’s been very rewarding to sort out mysteries.”
Sheffield also teaches at an academic center at the University of Iowa. He says, “I’m able to work with great people. I’m able to teach [students] how to do research and get them excited about having an impact on science and medicine. It is really rewarding to work with young people and to teach them not only about science, but about philosophies of life, and having a purpose. It’s exciting to try and figure out the things that no one has figured out before.”
Gregor Mendel was clearly not your average monk, but even he would never have guessed how his work would go far beyond peas and plants to inspire and influence genetics and geneticists today in a way that would bless future generations.
--Madeline A. Buhman ('18)