April 2012

Genes play a very important role in shaping how we look and act and even whether we get sick.
Most cells in the human body has 23 pairs of chromosomes. Heredity is the passing of genes from one generation to another. It plays an important role, but the environment also influences our abilities and interests.
The way it works is DNA contains four chemicals, adenine, thymine, cytosine, and guanine that that are strung in patterns on extremely thin, coiled strands in the cell. Each cell in our body contains about 6 feet of DNA thread. The DNA pattern is the codes for manufacturing proteins, which enables the body to work and grow.
As your cells duplicate, the pass genetic information to the new cells. Genes can be dominant or recessive. Dominant genes show their effect even if there is only one copy of that gene in the pair. Gene mutation occurs when all cells are aging been exposed to certain chemicals or radiation. Cells recognize mutation and can either repair themselves or cause illnesses like some cancers, by existing in the egg or the sperm cells and can be inherited by children from the parent, but doesn??™t always mean the person will actually get the disease. Because you inherit a gene from each parent, having one diseased gene usually does not cause any problems because the normal gene can allow your body to make the normal protein it needs.
Cystic Fibrosis
People who have one recessive gene for a disease are called carriers. And they don??™t usually have the disease because they have a normal gene of that pair that can do the job. When two carriers have a child together the child has a one in four chance of getting the disease gene from both parents, which results in the child having the disease. Cystic Fibrosis is caused by recessive disease genes from both parents coming together in a child.
If a person carries the dominant gene (disease) he or she will usually have the disease and each of the person??™s children will have a (50%) chance of inheriting the gene and getting the disease. Huntington??™s disease, which is a degenerative disease of the nervous system.

It is possible to inherit some types of chromosomal abnormalities; most chromosomal disorders are not from one generation to the next. Some chromosomal conditions are caused by changes in the number of chromosomes; they are not inherited, but occur randomly. An error in cell division called non-disjunction results produced in reproduction cells with an abnormal number of chromosomes. Ex: A reproductive cell may accidentally gain or lose one copy of a chromosome. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra missing chromosome in each of the body cells.
Changes in the chromosome structure can also cause chromosomal disorders. Some changes in chromosome structure can be inherited, while others occur randomly accidents during the formation of reproduction cells or in early fetal development. Because the inheritance of these changes can be complex, people concerned about this type of chromosomal abnormality may want to talk with a genetic professional.
Some cancer cells also have changes in the number or structure in the chromosomes. Because these changes occur in somatic cells (cells other than eggs and sperm), they cannot be passed from one generation to the next.

Bartoshesky, L. (2009). Genes and disorders. Kids Health,
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Genetics home reference. (2011).
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Mossler, R. (2011). Child and Adolescent Development. San Diego, CA: Bridgepoint Education, Inc.