Developing a Pedigree of a Family Tree
Type of activity:
- Inquiry Lab
- Off-site Activity
- Genetics (Most Applicable)
- Integrated Science 3
This project is designed to help students answer questions about how the study of genetics can be directly related to their own families.
Students create a family pedigree as a product of independent investigation. They learn the symbols used in pedigrees, as well as the usefulness in tracking genetic disorders. During cooperative learning activities, students learn to collect family history, to research genetic disorders using Victor McKusick's Mendelian Inheritance in Man, and to identify the concepts of Mendelian Inheritance. An oral and written report are required of each student.
Notes to teacher:
Studying the effects of genetics by completion of a family pedigree is an activity performed in many science classes, and there are a variety of ways to study genetics. This activity has been successful because it contains two important qualities necessary to hold student attention: (1) the activity is student-centered, and (2) genetics is one of those subjects that students hear about on a daily basis. I have developed the following method by modifying some published materials, including those authored by me in Biology: The Dynamics of Life, 1993 and 1995.
Characteristics such as attached or unattached earlobes, the ability to roll the tongue, the ability to detect the odor of asparagus in urine, and other genetic traits may be eas
ily traced in families. In this project, students choose one of these innocuous traits or any other genetic trait or disorder that might occur in their family. Ovarian cancer in women, color blindness, cystic fibrosis, neurofibromatosis, or sickle cell anemia are examples that have been used, but students may study any heritable characteristic that interests them.
Every ethnic and racial group has genetic characteristics that are localized within the group. This activity is individualized, and the genetic characteristic studied is determined by the student. Studying such characteristics allows students to see themselves as different, but it allows them also to see themselves as having information that can be shared with others. Because the students are given the power to determine the focus of their learning as I determine its direction, I can be assured that the needs of my students are met.
Students gather data by interviewing parents, aunts, uncles, grandparents, great grandparents, or any other person who has knowledge about their own family characteristics. In the interviews, students ask about traits that their family members have noticed that pass from generation to generation, as well as those that skip a generation. Notes taken during the interviews are included as additional information in the final project report. After completing the interview process and locating any available photographs of family and ancestors, students place their data on a Family Tree Data Gathering Chart prior to completing a pedigree which shows as many of the student's family and ancestors as possible.
1 or 2 weeks should be allowed for students to collect their family history information, and 3 to 4 55-minute periods of 2 90-minute periods will be required for the oral reports students present upon conclusion of their projects.
- Victor A. McKusick's Mende
lian Inheritance in Man: Catalog of Autosomal Dominant, Autosomal Recessive, and X-Linked Phenotypes, published by John Hopkins University Press
- Access to other descriptors of human genetic disorders such as those available from the March of Dimes are helpful.
- Poster board and markers
- Glue or paste
- Paper and pen
Students first are introduced to the concepts of Mendelian genetics and human genetics using slides, films, books, lectures, labs, etc. After students have a basic understanding, they are presented with this project problem: Choose at least one human genetic trait - autosomal dominant, autosomal recessive, or X-linked, but not one that is controlled by multiple alleles - observable in your family. Use McKusick's Mendelian Inheritance in Man to find out as much information about the trait as you can, including its McKusick number. Interview as many of your family members as possible, from as many generations as possible, and take notes about how the trait is inherited in your family. Ask family members about other traits they have noticed that seem to be inherited and what the suspected patterns are. You may wish to collect photographs (or photocopies of photographs, since you shouldn't damage those that may be family heirlooms) to use in your report. After you have collected your notes, construct a pedigree of the trait in your family members to good effect. You will make a short oral report and turn in your project notes, data, and pedigrees.
Grades are determined from a combination of the notes taken by the student, completion of the information required to complete the pedigree, completed pedigree, other information about traits family members have noticed and any conclusions that the student can make about them, and conclusions about what the student learned during the project. Students can receive extra credit for including photocopies of photos that show the traits expressed in their family as well as additional ped
igrees, posters or other 3-dimensional or other artistic pedigrees that the students might create.