A study by U.S. and Australian researchers is helping dispel the 40-year-old "thrifty genotype theory," which purports that certain minority groups are genetically prone to diabetes.
The study, co-authored by UC Irvine anthropologist Michael Montoya, along with an epidemiologist and population geneticist, analyzed existing genetic studies published across a variety of disciplines. The team found no evidence to support the widely held thrifty genotype theory, which suggests that cycles of feast and famine early in human history created a gene that helps the body use scarce nutrients a gene that leads to obesity and diabetes in comfortable, sedentary modern lifestyles.
"Our study challenges the presumption that Native American, Mexican American, African American, Australian Aborigine, or other indigenous groups are genetically prone to diabetes because the evidence demonstrates that higher rates of diabetes across population groups can be explained by non-genetic factors alone," said Montoya. The study helps explain why more than 250 genes have been studied as possible causes of type-2 diabetes, but together these genes explain less than 1 percent of diabetes prevalence worldwide.
The findings are published in the spring issue of the journal Perspectives in Biology and Medicine.
"When it comes to diabetes, we're finding that genes are no more important for ethnic minorities than for anyone else," said Stephanie Fullerton, a population geneticist and bioethicist at the University of Washington and co-author of the study.
Also, it was found that in most existing studies of the suspected genes that contribute to diabetes in ethnic minorities, researchers failed to control for the potential impact of social and environmental factors. Controls would have enabled researchers to see that other factors such as poverty, housing segregation or poor diet were stronger indicators of diabetes than genes. "Our study shows tha
Contact: Christine Byrd
University of California - Irvine