The genesis of permanent growth of the beak wattle of a wattle-type pigeon

Variation in size of warts located on the beak of wattle-pigeons represents a dominant trait of this breed. Excessive growth to extraordinary size in two breeds (barbs and carriers), in addition to a large beak, can cause losses due to the inability of the parents to feed the offspring properly. In older birds, respiration is impeded and the field of vision is limited. This permanent growth in barbs and carriers could not be attributed neither to an infection with papovaviruses, nor to the overexpression of the retroviral c-src-protooncogen. This finding, in conjunction with the genetic analysis, underlines that this prominent trait is genetically determined.