ASU genetics research sheds light on evolution of the human diet

February 12, 2009

CHICAGO - Diet - and how it has shaped our genome - occupies much of an evolutionary scientist's time. Anne Stone, associate professor of anthropology in Arizona State University's School of Human Evolution and Social Change, will discuss how diet holds keys to understanding who we are, how we live and form societies, and how we evolved from hunter-gatherers to agriculturists, all the way to modern urban dwellers, at the American Association for the Advancement of Science annual meeting. Her seminar - "Genetic Perspectives on the Evolution of Human Diets" - will be presented at 8:30 a.m. Feb. 13.

Researchers like Stone look to our closest relatives - the chimpanzee and other primates - for comparisons to humans in order to understand the unique development of the human body and how it is impacted by diseases and the environment.

"One area we look at is starch consumption, something prominent in both agriculturalists and hunter-gatherers," says Stone. A study she and graduate student George "P.J." Perry led on the amalyse gene (AMY1) copy number variation - the gene responsible for starch hydrolysis - produced one of the first examples of positive selection on a copy number variable gene in the human genome. The results show how different levels of AMY1 copy number differentiation is unusual in a population, and that individuals with high starch diets have more copies than those with traditionally low starch diets. Digestion of starches is critically important for energy absorption - especially during episodes of diarrhea. This research gives insight into why certain populations may weather diarrheal diseases better than others.

"To gain an even better understanding of this process in humans, we analyzed patterns of AMY1 copy number variation in chimpanzees and bonobos. We discovered that the average human has about three times more AMY1 copies than chimpanzees, which eat mostly fruit and far less starch than humans. And bonobos may not have any," says Stone. "This human-specific increase may have occurred with a dietary shift early in hominin evolutionary history. We know that starch-rich root plants were a critical food for early hominins, and may even have facilitated the initial spread of Homo erectus out of Africa."

Other genetic research on copy number variants in humans and primates includes examining the TAS2R gene family, the gene responsible for taste sensitivity to the bitter compound phynylthiocarbamide (PTC). "Sensitivity to bitter taste is an important means for animals to interact with their environment. These variants may be very significant from an evolutionary perspective, and they're important to study and understand," says Perry. "We talk about genetic diseases and cures, but first you have to find out what genetic differences are there so you can study what they're involved with and what they mean from a morphological variation and disease standpoint."

Identifying unusual patterns between species, such as copy number differences between humans and chimpanzees, can lead to identifying those that were involved in producing the evolution of human-specific traits. "This research not only illustrates the importance of studying genetic variation in other primates to understand our own genome better, but also sheds light on the diversity and adaptations of our nearest relatives," adds Stone.
-end-
Stone is one of the senior researchers, along with Charles Lee of Harvard Medical School's Brigham and Women's Hospital, on studies funded through the National Institute of Health and the National Science Foundation. She received her doctorate in anthropology from Pennsylvania State where she wrote her dissertation on the genetic and mortuary analyses of a prehistoric Native American community. Her undergraduate work in archaeology and biology was at the University of Virginia. Stone's interdisciplinary work in Arizona State University's College of Liberal Arts and Sciences primarily focuses on anthropological genetics - applying genetics to questions concerning the origins, population history and evolution of humans and the great apes. Her research has been featured on the covers of Nature (April 13, 2006) and Genome Research (Nov. 2, 2008), and in the Proceedings of the National Academy of Sciences (PNAS, May 23, 2006).

Arizona State University

Related Evolution Articles from Brightsurf:

Seeing evolution happening before your eyes
Researchers from the European Molecular Biology Laboratory in Heidelberg established an automated pipeline to create mutations in genomic enhancers that let them watch evolution unfold before their eyes.

A timeline on the evolution of reptiles
A statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts.

Looking at evolution's genealogy from home
Evolution leaves its traces in particular in genomes. A team headed by Dr.

How boundaries become bridges in evolution
The mechanisms that make organisms locally fit and those responsible for change are distinct and occur sequentially in evolution.

Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.

Paleontology: Experiments in evolution
A new find from Patagonia sheds light on the evolution of large predatory dinosaurs.

A window into evolution
The C4 cycle supercharges photosynthesis and evolved independently more than 62 times.

Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?

Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.

Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.

Read More: Evolution News and Evolution Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.