Other Free Encyclopedias » Medicine Encyclopedia » Genetics in Medicine - Part 1 » DNA Repair - Sources Of Damage, Base Excision Repair, Nucleotide Excision Repair, Dna Mismatch Repair, Future Directions - Types of DNA Damage

DNA Repair - Sources Of Damage

aging genetic chemicals cell cellular mutation

DNA is subject to spontaneous instability and decay. In addition to spontaneous damage, cellular DNA is under constant attack from reactive chemicals that the cell itself generates as by-products of metabolism. Moreover, the integrity of cellular DNA is assaulted by such environmental threats as X rays, ultraviolet radiation from the sun, and many chemical agents, some of which are products of our industrialized society.

Since mutations can be introduced into DNA as a consequence of DNA damage, there is currently great interest and concern about the expanding list of chemicals released into the environment. In humans, damage to DNA has been implicated in many cancers as well as in certain aspects of aging. Genetic diseases such as cystic fibrosis and sickle cell disease can be caused by a single DNA mutation in one gene.

Figure 1. Four types of mutation: (A) complete loss of a base. (B) Loss of an amino group, converting a cytosine to a thymine. (C) Addition of a small alkyl group, such as-CH3. (D) Reaction with oxygen.

DNA Repair - Base Excision Repair [next]

User Comments

The following comments are not guaranteed to be that of a trained medical professional. Please consult your physician for advice.

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or