Department of Anthropology, University of Wisconsin-Madison
Friday All day, Plaza Level
Celiac disease (CD) is a common, highly heritable (Nistico et al., 2006) small intestinal inflammatory condition induced by wheat gluten and related proteins from rye and barley (Sollid, 2000). When left untreated, the clinical presentation of CD can include failure to thrive, malnutrition, and distension in juveniles. These symptoms are referred to as the tip of the “celiac disease iceberg,” as the disease can additionally lead to severe vitamin deficiencies, anemia, and osteoporosis (Barker and Liu, 2008). Therefore, CD potentially had a negative effect on fitness in past populations utilizing wheat agriculture.
To date, three studies have addressed the question of natural selection in CD (Barreiro et al., 2009; Soranzo et al., 2009; Zhernakova et al., 2010). Results from these studies indicate that at least some genetic loci associated with CD risk have undergone recent positive selection. These studies also suggest the possibility that risk for common autoimmune conditions such as CD may be the result of past positive selection on immune related loci in the genome to fight infection. Under this evolutionary scenario, disease phenotypes may be a trade-off from positive selection on immunity. If true, a signal of natural selection across the CD risk network is expected. The current study represents the first complete analysis of natural selection on risk loci for CD from the Catalogue of Genome Wide Association Studies. Results from linkage based selection tests on individual risk loci and the complete set of risk loci as a functionally-related network are reported.