Wolbachia PCR – Discover the Microbes Within

Wolbachia PCR Lab Introduction
In this lesson, students use PCR to determine whether or not an insect they have collected is infected with a fascinating bacterial parasite named Wolbachia. The Wolbachia genus of bacteria lives within the reproductive cells of insects and arthropod species resulting in the feminization of host populations. Students will consider the impact of infection on their local insect populations and ecosystem where reproductive success of females is tipped in favored over males. Students are also introduced to how Wolbachia is being used to control mosquito-borne diseases like Dengue and Zika.
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    In the lab portion students extract DNA from collected insects, use PCR to amplify gene segments specific for insects and the presence or absence of the Wspec gene of Wolbachia, then visualize results using gel electrophoresis. In addition to the fundamentals of PCR, this lesson explores symbiotic relationships, population limiting factors, cellular determinants of sex, ecosystem interdependence, and speciation.
    The idea and methods for this lab are based on the materials developed by Dr. Seth Bordenstein and other scientists of the Wolbachia Project at Woods Hole Marine Biological Laboratory (MBL). We gratefully acknowledge Dr. Bordenstein, Michael Clark, Michele Bahr, and others at MBL for their generous support in developing this curriculum.

Lesson Resources
Student Guide – Download and edit student worksheets to be completed during the Wolbachia PCR Lab.
Lesson Slides – Articulates with the student guide above and accompanying lesson plans below.
Lesson Plan – Suggested times for pacing, sequence and activities. Includes vocabulary tool, student readings, and other lesson resources
Supplemental Resources – Includes background information, outside articles, videos, and more related to the lab.

Lab Resources
Student Lab Protocol – Students follow these instructions when doing the Wolbachia PCR Lab.
Preparing the Classroom for the Lab – How to set up group stations for this lab experience.
Inventory Guide – Reagents and materials checklist for one classroom kit. Includes equipment and classroom needs for the lab.

  • Perform DNA Extraction, PCR, and gel electrophoresis to determine Wolbachia infection rate in local insect populations
  • Describe the symbiotic relationship between Wolbachia and its insect hosts including the different reproductive affects of infection
  • Explain how Wolbachia infection could affect local insect populations and the ecosystem over time and communicate this information by creating an infographic

Disciplinary Core Ideas:
LS2.A – Interdependent Relationships in Ecosystems

  • “…this tension affects the abundance (number of individuals) of species in any given ecosystem.”

LS3.B – Variation of Traits

  • “…environmental factors affect expression of traits…”

LS4.C – Adaptation

  • “..changes in environment have contributed to the expansion of some species, the emergence of new distinct species as populations diverge under different conditions, and the decline–and sometimes the extinction–of some species.”

Science and Engineering Practices:
Analyzing and Interpreting Data
Constructing Explanations
Communicating Information

  • Students analyze PCR data to determine the Wolbachia infection rate of local insect populations. They then use this evidence to explain how this may affect insect populations and the ecosystem over time and make an infographic to communicate their ideas.

Crosscutting Concepts:
Cause and Effect

  • Students identify patterns in their Wolbachia infection data and describe cause and effect relationships between Wolbachia, its individual insect host, insect populations, and ecosystems.

Familiarity with the following biology concepts may be helpful for students prior to using the lesson resources.

  • Experience with DNA extraction, micropipetting and gel electrophoresis
  • Definition of biological sex in relation to genotype and phenotype
  • Levels of organization in an ecosystem

Kitty MeiWolbachia – Discover the Microbes Within