ABSTRACT
Radiation can also cause larger-scale errors involving many nucleotides. In some cases, the change in the chromosome is visible with a microscope (called chromosome aberrations). Some important types of chromosome aberrations are deletions, amplification, and translocation. Deletions are simply loss ofa segment ofDNA with the consequence
that a number of different proteins, coded by the deleted region, are not made at all. This kind of error is thought to occur in the childhood cancer retinoblastoma. The amplification type of error, with repetition of a whole sequence of DNA bases, also occurs in some childhood cancers. Translocation is what happens when one piece of DNA is physically moved and joined onto some unrelated piece of DNA. Some kinds of human leukemia may result from this type of error.
