Studying Living Organisms

The Value of Genetic History

Janell Mead
Woodrow Wilson Biology Institute

Target age or
ability group:
11-12 grades.
Class time
1-2 weeks.
Materials and equipment: Pattern sheets, Color pencils, Large sheets of paper, Glue, Black markers
Summary of activity: This activity aims to help each student become familiar with his or her genetic background and the value of this information. This is done by having students assemble their own pedigrees using star patterns for each family member and coloring in various dominant traits. While working in the gym, these patterns are arranged on long strips of paper making large, colorful family pedigrees.

Teacher Instructions

The need for knowing one's genetic history is becoming increasingly apparent as each new disease marker is identified. Knowing the presence of genes for heart disease, breast cancer, and a wide variety of other human ailments can allow for the prevention of problems faced in the past. For example being aware one is at risk for high blood pressure, allows you to make more intelligent decisions about your lifestyle.

After asking students in my genetics class to diagram a family tree and watching them struggle, I realized the influence our changing society is having on this. Families no longer remain in the same area. Often, family members move so frequently, or so far away, ties are lost. Many students are from broken homes and never meet their biological relatives. Some students don't care about these very important people.

With the increasing use of genetic information I believe we should emphasize the value of one's genetic history. While students are researching their past, I present information about Nancy Wexler and her work on the Huntington's gene. We examine the Russian royal pedigree of hemophilia. I provide the latest articles concerning our ability to search our own genes and show videos of people who have pursued this. We discuss the pros and cons of genetic testing and of knowing what is in your future. One activity I use at this time is the BSCS Human Genome Activity booklet case study of "Nathaniel Wu." As the students bring in information about their family, they begin to assemble a family tree using my family as a model.

My great grandfather Philip had 14 children, many of whom remained in the area to farm. I am fortunate these relatives have stayed in touch and many meet annually for a family reunion. This made it very easy for me to survey individuals and to get information. The original survey dealt with six "non-threatening" traits: widow's peak, earlobes, cleft chin, dimples, freckles and tongue rolling. Since then, I have begun collecting data on the more personal items such as cancer and diabetes. I explain to the students that people might feel threatened or embarrassed by these more personal characteristics and it might be best to work up to them.

Using the information I have amassed, we indicate the dominant traits on a six segmented star pattern (any pattern will do) with the person's name in the middle. Each segment is colored if the individual is dominant for that trait. We color the center pink if the individual is a female and blue if the individual is a male. The patterns are arranged on long strips of brightly colored paper about four feet wide. Lines are drawn to show relationships. The genetically related individuals are outlined in black. This activity needs space for the students to spread out. We work in the bleacher stands of the basketball gymnasium. The phenotypes are easily observed and often hypotheses can be made as to genotypes. By looking at the overall patterns we can see the flow of traits through the generations, introductions of new traits by people marrying into the family, and a general shift of trait frequencies. Predictions are sometimes made for future offspring.

By this time, students have been able to collect information and to assemble their own family tree. Sometimes, I will have adopted or foster children. They usually want to research the family they are living with but if this is a problem, they are given information about my family to use. Some students want to use my family just because the data collection has been done. I try to encourage all students to research their own genetic history if it is possible.

I encourage the students to find important genetic information about their relatives and to record this for their personal use at a later date. They see the need (and relevance) of this activity and will try to "out-do" their classmates. The students show a great interest in doing this and I often receive positive comments from their families. This type of activity lends itself to a wide variety of assessment models. I recommend that each instructor develop their own set of objectives to be given to the students before the beginning of the research.

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