Celiac disease (CD)is a common, usually inherited human disorder of intestinal inflammation that is triggered by eating gluten, a major protein in wheat and other cereal grains. It is the most frequent food intolerance. One of the three genes involved is for SH2B3, a protein involved in innate, nonspecific immune response to bacterial pathogens. Celiac sufferers frequently have a particular allele of this gene. It is so common that which of the following might be hypothesized?

Question

Quizplus · Accepted Answer

The high frequency of the particular allele of the SH2B3 gene in celiac sufferers suggests that it has been positively selected for. One possible explanation is that it provided an advantage during a period of frequent bacterial infections, possibly by enhancing the innate immune response to these pathogens. This hypothesis would also be supported by the fact that celiac disease is triggered by consuming gluten, a component of cereal grains that were not widely available until the development of agriculture, which also coincided with increased population density and the spread of infectious diseases. Therefore, it is unlikely that the gene is common to all primate or mammalian genomes or that it codes for a T-cell receptor for a common bacterial component. It is also unlikely that the wild-type allele was selected against during periods of frequent bacterial infections, as wild-type individuals without celiac disease still exist today.

Celiac Disease (CD)is a Common, Usually Inherited Human Disorder of Intestinal