A 3-base deletion in the AAUAAA sequence in the 3' untranslated region of an mRNA that eliminates the AAU, thereby preventing RNA polymerase from polyadenylation the mRNA would have the effect of; decreasing the number copies of the polyeptide that would be translated from this mRNA. A deletion is a mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication.
