LESSON THREE

Who's Who and How Do You Know for Sure? DNA Fingerprinting.

This lesson is intended for a high school biology class with access to a lab. It may be applicable in an interdisciplinary setting. The teacher sets up a Discovery learning situation and set of problems based on the topic of DNA. The Double Helix (THE DOUBLE HELIX: A PERSONAL ACCOUNT OF THE DISCOVERY OF THE STRUCTURE OF DNA, by James D. Watson, New York, Atheneum, 1968. Movie: THE RACE FOR THE DOUBLE HELIX. Web Information at http://us.imdb.com/Title?0093815) might be available. Students might be encouraged to do web and library-media center searches on DNA, forensics, and other topics that they see as related to this general area: coding, court reports, information theory, genetics. As this unit has practical lab experience embedded within it, it may be used as a follow up to a more general study of genetics.

The teacher leads a class discussion on DNA. Through discussion various topics may emerge:

• The term "fingerprinting" is used to indicate that each individual can be identified by the unique pattern that exists on the fingers of that individual. No two people have identical patterns. This is also true of an individual's DNA. No two people have the same DNA. Researchers can isolate DNA from an individual and create a "fingerprint" of that individual. These techniques can also be used to determine if an individual carries a defective gene that may cause or predispose the individual to a genetic disease.

• This technology has many applications. Suspects have been convicted, as well as acquitted, of crimes based on evidence found at the scene of the crime, such as a drop of blood. Paternity cases have been argued using this technology: the DNA of the child is compared with that of the possible father to see if the child has any of the same patterns of DNA, indicating a biological relationship. Individuals can also be tested for genetic diseases that run in a family.

• There are controversies surrounding this technology. Some argue that the techniques used are not fool proof and therefore they should not be used to convict someone of a crime. Some people worry about who should have access to the information obtained from individuals tested for genetic diseases. For instance, many believe insurance companies would deny coverage for people who are determined to be predisposed to diseases based on information gained from DNA fingerprinting. Other types of discrimination may occur based on this information. For instance, an airline may not hire a pilot if that person was found to have a gene causing a predisposition to high blood pressure. This person may be more likely than most people to have a heart attack, and this would endanger many lives if the person were piloting a plane when and if a heart attack occurred.

• What are some other possible uses of this technology? What are some other benefits and problems associated with DNA fingerprinting?

• If a genetic disease were carried in your family, would you want to be tested for it? Would you want your unborn child tested for it?

• Who should be given access to information gained from DNA fingerprinting?

At the end of class discussion, students should be asked to formulate plans for research. There are many issues involved in this topic: what further information do you need in order to continue discussing these questions and to make informed decisions about this technology?