Sturgeon Lesson Plan #10
Lesson Title: Estimation of population allele frequencies and assignment of unknown individuals to population of origin
Summary:
In absence of other sources of information, genetic data can be used to determine the degree to which populations are reproductively isolated. In the absence of migration between populations and reproduction by immigrating individuals, over time populations will diverge in allele frequency. The rate at which the divergence occurs will depend on (a) the degree of isolation and rates of exchange of individuals, (b) the population size (smaller populations will diverge more quickly than populations of larger size), and (c) the time of separation.
This exercise is designed to allow students to gain knowledge in manipulation of population genetics data. Summaries of allele frequencies and measures of diversity and inter-population relationships will be made. The students will estimate simply likelihoods and use genotypes to estimate population of origin. Students will be asked to draw conclusions about aspects of data that would be most important to make assignment decisions. Students are asked to make recommendations about the implications of findings to people would be managing the fishery.
Objectives:
- Develop skills in manipulation of summarization of genetic data
- Develop math skills to estimate simply likelihood functions and statistical tests of hypotheses
- Draw conclusions about the quality of data and data requirements to increase the accuracy of tests
- Discuss and draw conclusions concerning the implications of the data and place results into a broader context
Subjects: Science, Math
Grade Level(s): 10-12
Content Standards:
Duration: 2-3 days
One full classroom session could be devoted to lecture and discussion of algebra associated with the handouts on population genetic terms and estimation of allele frequencies, summary diversity measures, and likelihood analysis
Materials/What you Will Need:
- Pdf files of introductory population genetics
- Pdf file of power point presentation on assignment tests
- Excel spreadsheet with data and instructions
- Background pdf file
Background:
Video may require Adobe Flash Player
Information on the specific details of the assignment are provided in the pdf file on background and in the explanation worksheet of the Excel file. Teachers can expand requirements based on background materials on the web site in the ‘Genetics Section’ and in the background materials.
Procedure:
Background materials can be sent to students and discussed in class as a lecture. Another day could be spent individuallly or in groups going over the date and working on the assignment. The final product would be a write-up of results. Oral presentations of results by groups or individually could be made during the 3rd class session. Students would likely learn from other perspective offered by their peers.
Extended Learning Opportunities:
The exercise offers a valueable lesson in taking data that was collected to solve a problem, develop summaries of data to answer the question, and summarize findings and implications of findings. The background pdf files contain summarizes of information that could be used to expand student understanding of how levels of genetic diversity within and among populations can be affected by aspects of the enviroment and the organisms ecology.
Assessment and Evaluation:
- Quality and depth of students summaries and presentations
- Demonstration of thoroughness in process of summary and extrapolations of data to problem.
- Demonstration of ability to draw conclusions from data and to critically critique the manner in which data were collected and analyzed to improve inferences in the future.
- The background materials contain a considerable amount of information about genetics that together with the Genetics Section on the web site could be used in examinations in the area of genetics.
Lesson Sources:
Genetics Section of this web site
assignment testing background (PDF)
background for lesson 10 on assignment testing (PDF)
introductory genetics (PDF)
summary of algebra (PDF)
measures of diversity (PDF)
Data Sources:
student example assignment test