Genetic Mutations and Health

This section presents basic information about gene mutations, chromosomal changes, and conditions that run in famihes.  

Gene mutations occur in two ways they can be inherited from a parent or acquired during a person s lifetime. Mutations that are passed from parent to child are called hereditary mutations or germhne mutations (because they are present in the egg and sperm cells, which are also called germ cells). This type of mutation is present throughout a person s hfe in virtually every ceU in the body. 

Mutations that occur only in an egg or sperm cell, or those that occur just after fertdization, are called new (de novo) mutations. De novo mutations may explain genetic disorders in which an affected child has a mutation in every cell, but has no family history of the disorder. 

Acquired (or somatic) mutations occur in the DNA of individual cells at some time during a person s hfe. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during ceU division. Acquired mutations in somatic ceUs (ceUs other than sperm and egg ceUs) cannot be passed on to the next generation. 

Mutations may also occur in a single ceU within an early embryo. As aU the cells divide during growth and development, the individual whl have some ceUs with the mutation and some ceUs without the genetic change. This situation is caUed mosaicism. 

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But the problems about which public opinion has been most sensitive have turned out to be concerns about the environment and more particularly atmospheric pollution, owing to their consequences on human health genetic mutations and cancers, decrease in the effectiveness of the immune system, diseases of the respiratory system, the eyes, the skin. 

In approaching the study of the molecular mechanisms of heredity, this chapter first discusses the structural and functional roles of the genetic material, DNA. This includes an analysis of its replication and susceptibility to mutation. The health-related aspects of the use of recombinant DNA techniques are considered, and examples of then-use in the analysis of several human genetic diseases are used to illustrate the biochemical side of genetics. 

As mentioned earlier, the stoppage of fast electrons generates x-rays, which are hazardous to human health. X-rays cause cell damage that can lead to cancer formation or genetic mutations. Even at low dosage, x-ray exposure can cause skin burning and general radiation syndrome. 

Mehta, R.D. von Borstel, R.C. (1985) Tests for genetic activity in the yeast Saccharomyces cerevisiae using strains D7-144, XV185-14C and RM52. Prog. Mutat. Res., 5, 271-284 Ministry of Social Affairs and Health (1998) Finnish Occupational Exposure Limits 1998,... 

Xenobiotics, for the most part, have limited biological half-lives. The extent of their influence on the biological living system is limited on the basis of the amount absorbed and the duration of their presence within the system. Once exposure to a pesticide chemical occurs, individuals need not be unduly fearful of adverse health impacts slowly and relentlessly progressing regardless of dose and duration of exposure. There are effects such as cancer induction and genetic mutations which have yet to be characterized and fully understood from a chemical standpoint. Consideration of these special conditions has been the subject of entire seminars and obviously cannot be covered fully in a presentation such as this. 

First The impact of mutation on human health and welfare is enormously diverse—as diverse as the range of genetically influenced traits. The effects are spread over many generations with no certainty about when a particular trait will be expressed. Ihe Committee knows of no reliable way to estimate the total genetic impact of an increased mutation rate. We have to be content with estimating the earlier and more tangible part of the effect, that caused by dominant gene mutations and chromosomal aberrations. 

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