Heartworms are spread to dogs through mosquito bites. Up to 14 inches long, a heartworm lives in the heart and the arteries that carry blood from the heart to the lungs. Heartworms affect how the heart functions and how blood clots and is likely to cause death if untreated. Monthly heartworm preventives are effective.
missense mutation. A substitution of a single DNA nucleotide for another. This results in the transcription of a different amino acid than is normally found in the protein coded by the gene. Missense mutations are found in diseases such as sickle cell anemia.
-The replacement of one nucleotide base pair by another. 1. Silent Mutation - a base pair substitution mutation producing an mRNA codon specifying the same amino acid as the wild-type mRNA. 2. Missense Mutation - a base pair substitution that results in an amino acid change to the protein. 3. Nonsense Mutation - a base pair substitution that creates a stop codon in place of a codon specifying an amino acid. Two types of base pair substitutions that can occur.