Warm Up Prepare to text your responses. Mrs. Lloyd’s code: 37607

DNA and Modern Genetics March 2008 DNA and Modern Genetics Life Science/McDougal/Littell

Changes in DNA Can Produce Variation Most DNA is the same for all individuals of a species. DNA sequences can change while copying. This is what makes one organism different from another.

Things That Damage DNA DNA is affected by the environment. Ultraviolet radiation X-rays Natural and human made toxins Chemicals

Changes in DNA Can Produce Variation Given the large amount of DNA and the number of times it is copied, changes are bound to happen. Any change in DNA is called a mutation. Mutations in genes can have three possible outcomes.

Mutations The mutation can have no effect. Because there is a pair of genes in every cell, the gene without a mutation may be able to make up for the one that is not working. The mutation can have a minor effect. A change in a gene that codes for the protein for skin color might affect how dark or light a person's skin color is. This would affect not only skin color, but eye or hair color too. But the change would be in appearance only. The mutation can have a major effect. This could be good, such as increased resistance to disease. This could also be bad, causing a genetic disease. If a mutation occurs in DNA that is non-coding, the mutation will probably have no effect.

Genetic Disorders Genetic disorders are diseases that result from mutations that affect the normal functioning of a cell. - Tay-Sachs -fatty tissue builds up in the brain affecting a baby's sight, hearing, movement, and mental development. - - Cystic Fibrosis -mucus build up in the lungs -Albinism- partial lack or total absence of melanin in the skin Sometimes people carry a tendency for a disease - Diabetes -Glaucoma -Alzheimer’s Disease -Emphysema

Genetic Disorders Genetic disorders can be inherited. A person's behavior can affect whether a mutation comes about, such as smoking or not smoking. Ex: Sickle cell disease is an inherited disorder.

Sickle Cell Anemia

Sickle Cell Anemia http://www.dnai.org/d/index.html

Cancer is a group of genetic disorders that affect the cell cycle All cancers are characterized by uncontrolled cell division. Normal cells divide only enough so the organism has the number of cells it needs to function properly. Cancer cells can also spread from where they started to divide to other tissues, and can keep dividing indefinitely. http://www.nobel.se/medicine/educational/2001/cellcycle.html

Cancer Some cancers are caused by mutations during a person's lifetime. Some cancers are caused by harmful substances, such as nicotine in cigarettes, or by ultraviolet and nuclear radiation. http://www.biotechnologyonline.gov.au/biotechnologyonline/popups/int_dogcloning.html http://www.biotechnologyonline.gov.au/biotechnologyonline/popups/int_thylacinecloning.html

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