Medical Genetics 1. Base(s) in DNA is (are) changed to other(s), or a base(s) is (are) added or removed 2. Rearrangements of the chromosomes occur and are also consideredMedical Genetics 1. Base(s) in DNA is (are) changed to other(s), or a base(s) is (are) added or removed. 2. Rearrangements of the chromosomes occur and are also considered