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 most common type of mutation; a base-pair substitution in which the new codon makes sense in that it still codes for an amino acid. missense mutation (A in the picture below), A point mutation in which one or more nucleotides pairs are lost from a gene is called a(n) ______.