DNA Damage and Repair

DNA is the critical molecule of life: it is the blueprint of the creature encoded in the genes. DNA is an indispensable part of the cell. Other parts of the cells such as the proteins, lipids and RNA can be replaced if need be. DNA, if lost or damaged cannot be replaced.

DNA damage can have two main results: the cell mutates or the cell dies. This means that the genes either change their properties or else they cease to exist. The bulk of mutations that occur in the DNA are either harmful or have no effect (are neutral). The elements that can harm the DNA and cause mutations are known as mutagens. Free radicals are the most common form of mutagen. Other mutagens are compounds of N-nitroso, asbestos, coal tar and aldehydes. Most mutagens are also carcinogenic (meaning that they can cause cancer).

Mutagens attack the DNA on a regular basis. The majorities of mutagen such as oxygen free radicals or certain aldehydes are regular bi-products of the body's metabolism and cannot be avoided. Other mutagens like cigarette smoke or acetaldehyde (a byproduct of alcohol) are easier to avoid. Yet another category of mutagens comes from pollution in the environment. Different kinds of radiation can also produce mutations. UV radiation primarily affects the eyes (both the cornea and the retina) and the skin. X-rays which are high energy forms of radiation can cause mutations throughout the body.

Mutagens attack the DNA on a regular basis. The majorities of mutagen such as oxygen free radicals or certain aldehydes are regular bi-products of the body's metabolism and cannot be avoided. Other mutagens like cigarette smoke or acetaldehyde (a byproduct of alcohol) are easier to avoid. Yet another category of mutagens comes from pollution in the environment. Different kinds of radiation can also produce mutations. UV radiation primarily affects the eyes (both the cornea and the retina) and the skin. X-rays which are high energy forms of radiation can cause mutations throughout the body.

Mutagens attack the DNA on a regular basis. The majorities of mutagen such as oxygen free radicals or certain aldehydes are regular bi-products of the body's metabolism and cannot be avoided. Other mutagens like cigarette smoke or acetaldehyde (a byproduct of alcohol) are easier to avoid. Yet another category of mutagens comes from pollution in the environment. Different kinds of radiation can also produce mutations. UV radiation primarily affects the eyes (both the cornea and the retina) and the skin. X-rays which are high energy forms of radiation can cause mutations throughout the body.

The theory that the buildup of mutations within the body is a key part of aging is not a new one. It has been plausibly demonstrated in a number of studies that maximal life span has a direct correlation with the efficiency of DNA repair in the body. People have the most effective repair systems and therefore the longest life spans among mammals. It has also been proved that the level of mutations goes up as the individual grows older. One possible reason for this is that in the course of time, the repair system itself is slowed by mutations so the rate of correction is slowed down accordingly. Additionally, as we get older, the body produces more free radicals, thus resulting in a higher number of mutations and other DNA lesions. The DNA damage theory of aging and the free radical theory are closely linked since DNA is one of the main victims of free radicals.

What are the effective ways of lowering levels of DNA damage and improving DNA repair? The key thing to do is to try to minimize environmental damage such as spending too much time in the sun or smoking. People who have trouble giving up smoking should at the very least switch to a low tar content cigarette. You will also need to make sure that you take basic precautions from over exposure to the sun. Another way to reduce damage to the DNA is by making sure that you keep your antioxidant defenses at their maximal levels. (see our article on free radicals)

Currently, there is no proven way to improve the efficiency of DNA repair in cells. These systems are very complicated and contain a large variety of enzymes. DNA repair systems vary from species to species. Incomplete or improperly done repair can lead to mutations; these mutations are the main force of genetic change and in turn of evolution. Increasing the level of mutations causes a species to evolve more quickly but it can also shorten the lifespan of an individual. The reverse can also be true. This explains why it would be highly improbably for an organism to develop a perfect repair system through the course of natural evolution.

People have the most effective DNA repair systems among the various species of animals. We have a relatively low level of mutations so we age at a slower pace. Ironically, the effective repair system serves as a road block to lengthening our maximum lifespan. It is more likely that an increased level of DNA repair in humans will occur through scientific means rather than via natural evolution. There is indeed, some good research being done on that very issue. The main DNA repair enzymes have to use special DNA precursors: which are called deoxyribonucleaotides. Deoxyribonucleaotides are created from other precursors (ribonucleotides) as well as by ribonucleotide reductase (RR) which is the key enzyme. If the activity of RR is raised then the number of deoxyribonucleaotides goes up and the DNA repair system works more efficiently. Research shows that the substances that can stimulate RR can partially protect animals from raised levels of radiation, presumably by augmenting the quality of DNA repaid. It is possible that a similar method could be used to slow the normal aging process.

Aging is a complex set of processes that involve a diverse set of conditions and reactions. This is why the aging process has been challenging to define; it is also why there are multiple theories on it. However, aging processes can be divided into two groups: the amassing various degrees of damage to the cells and the genetically programmed process.
Free radicals are the chemicals in the body that have an unpaired electron This means that they are very dangerous as they can behave in a erratic manner which can be very damaging to the effective functioning of the body.
Could aging be explained as what happens once cells have reached the Hayflick limit and are no longer able to divide? There is no conclusive answer to that question at this time. It seems that in certain tissues, including the skin and the lining of blood vessels the Hayflick limit may be a key to the aging process.
Is there a centralized aging clock in humans that dictates the pace at which all of the bodily systems run? Yes and No... Studies have not yet found a specific central mechanism that is solely responsible for aging. However, there is a system of development.
Certain substances that contribute to the aging process can be avoided. A good example of this is tobacco tar. Other contributory substances are not as easily avoided as they are key parts of the metabolism. The best example of this is glucose.
The majority of energy that is produced in the cells is done by the mitochondria. Cell function is dependent on the mitochondria providing energy to the rest of the system. Mitochondria are also the main factor behind free radical damage.
One of the most important defense mechanisms in the body is inflammation. It is a key to survival but at the same time appears to add to the pace of aging and the speed of the onset of degenerative diseases.
The body's metabolism produces waste on a regular basis. The majority of bodily waste is expelled through breathing, urine, feces and sweat. The most easily disposable waste is that which is composed of small molecules like urea, carbon dioxide and electrolytes.
Stress has been closely linked to the development of age related diseases and to the aging process as well. Stress response is basically a complicated adaptive reaction in the body.
There are two commonly asked questions about the lifespan of humans. The first is why does the rate of aging differ so dramatically among different species of animals? The second one is why are there more short lived species than long lived ones?
Research on the prolonging of life, studies of people over 100, historical records, and common sense all show us that to live a long life you need to do at least some of the steps in this article.
The greater our comprehension of the aging process the more ways that scientists find to try to extend the average life span. Ironically, the most effective means of anti-aging intervention has been the same for the past 50 years; eating less!!