GED Science: Mutations
Some differences between parent and offspring, and some differences between siblings, can be explained by the passing on of different alleles, the differential expression of some genes, and the sex of the offspring. However, there is still one other category that explains differences in traits between parent and offspring. Mutations are random changes in DNA that can be either beneficial, damaging, or neutral. Remember that because DNA contains the code to produce proteins, that mutations in the DNA could cause changes in the proteins produced. In the case of sickle cell anemia, a mutation to a single base pair results in an irregularly-shaped hemoglobin, which causes the blood difficulty in transporting oxygen through the body. An example of a good mutation would be the change in a single gene that causes a protein to be absent from the surface of the cells in your body. Due to the absence of this protein, the HIV virus is unable to enter and infect your cells.