Oats are a species within the grass tribe Aveneae, which is in the Pooideae subfamily along with Triticeae (contains wheat, rye, barley and many other genera).
With coeliac disease risk is increased with the consumption of Triticeae glutens, and this also increases risk in juvenile diabetes whereas other cereals also appear to play a role.
Triticeae cultivation may apply negative selection on DQ8.