Procedure

Time: Approximately 30 minutes.

Materials: Computers with Internet access, Student Directions, Microsoft PowerPoint and Excel or similar programs, and referenced PowerPoint (genetics.ppt) and Excel (genetics_worksheet.xls & cumulativedata.xls) files.

Prerequisites: This activity is designed for students who have a basic understanding of human genetics and some knowledge of recessive and dominant inheritance.

Implementation: This RWLO MUST be implemented during class time as it requires the participation of all students to complete the class poll. At a minimum, one computer connected to a presentation device is required or each student/small group should have access to a computer.

Steps:

Provide access to the Student Directions and/or print and distribute the Student Worksheet (genetics.doc - 1.2 MB) located in the Content Material section of this RWLO.   Review the Background Information for the Human Genetics: A Worldwide Search for the Dominant Trait telecollaborative project.   Present in class or have students access the following short PowerPoint presentation "Human Genetics: Dominant & Recessive Traits": genetics.ppt (551 KB). The presentation describes the following four genetic traits included in the project survey (the dominant trait in each case is shown in red): Free vs. Attached Earlobes Straight vs. Curved Thumbs Bent vs. Straight Pinky With vs. Without White Forelock   Have students find a partner and determine, for each of the traits, whether they have the dominant or recessive trait. Students may work in small groups if that is easier. They should use their best judgment to determine which traits they have and answer whether they think the dominant trait is the most frequently occurring once they are finished.   Explain that the class will now conduct a simple poll to see what everyone has found. You can use the Excel spreadsheet (genetics_worksheet.xls) to tally up responses or just keep track of the responses on paper. For each of the traits, ask the students to raise their hands if they have one of the dominant traits. For example, ask how many people in the workshop have free earlobes and record the results. The remaining number of people will have attached earlobes. Do this for each of traits and note the percentage of students who exhibit each of the dominant traits. Students should complete the questions. Often, there are very few people who have a white forelock, yet this is a dominant trait.   Explain that archived data accumulated from schools participating in the Human Genetics: A Worldwide Search for the Dominant Trait since 1998 is available. Download and open the cumulativedata.xls (7.5 KB) Note and mention data has been collected for more than 92,000 individuals over the course of the project. Ask the students to calculate the percentage for the dominant and recessive characteristics for each of the surveyed traits (earlobe, thumb, pinky, and white forelock). Based on this data, students should now describe their reasoning behind their conclusions.

(NOTE: this RWLO is based on the Human Genetics: A Worldwide Search for the Dominant Trait Project)