Biotechnology and the Human Body

Mutations may result in genetic disorders. Scientists have identified about 3000 diseases linked to genes. Genetic disorders may produce physiological and/or physical abnormalities or malfunctions. They may be diagnosed by looking at magnified images of a person's chromosomes which is called a karyotype. Click HERE to make a karyotype.

Click HERE for a website which will review how the processes by which mutations occur, examine some common mutations and their corresponding syndromes. The activity at the end will help you review the genetic defects associated with each syndrome.

In some cases, defective genes may be replaced by normal ones in a process called gene therapy. One method uses an altered virus as a vector for healthy DNA which it inserts into the patients bone marrow cells. The figure below illustrates this process. Click HERE to view a video which illustrates the process using the example of the first person - a 4 year old girl- to receive gene therapy.
The gene therapy examined here uses somatic cells to treat a patient with an inherited disease. The person's reproductive cells will, however, remain unchanged and the disease will be passed onto their offspring. Much ethical controversy exists over treating these cells.

The genome is the complete set of genes found on all the chromosomes of an organism. Knowing the location of genes on each chromosome will be an ideal tool for diagnosing genetic disorders. The Human Genome Project began in 1990 and is devoted to mapping the entire human genome. Click HERE to watch a video on the human genome.

Not all faulty or missing genes can be replaced easily. Bacteria or animals can be used to produce the missing gene products. For example, diabetics cannot produce their own insulin ( a hormone that regulates sugar levels within a person's blood). The gene for insulin production was transferred into a bacteria, which now produce insulin at low cost. Human growth hormone (to treat growth abnormalities) and interferon (a protein for the immune system) have been produced in this way as well.

In animals, human genes are added to the fertilized egg of parents. Usually the gene codes for the production of a protein that can be collected in the animal's milk. An example is Willow, a goat and Canada's first transgenic organism. Willow excretes a human protein in her milk. Click HERE to watch a video on transgenic animals.