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Baby Doe v. The Prenatal Clinic

When Cell Division Goes Awry


Author(s)

Norris Armstrong
Biology Department
University of Georgia
narmstro@uga.edu

Abstract

This "clicker case" presents a fictionalized story about a couple ("John" and "Jane") whose new baby is born with Down syndrome; the parents are suing the prenatal clinic where Jane received her care, blaming the clinic for the baby’s condition. Designed for an introductory biology course, the case has students assume the role of an expert witness hired by a law firm to give evidence in the case. To help determine the cause of "Baby Doe’s" condition and whether anyone can be held responsible for it, students need to help the jury understand the process of cell division. In particular, they must explain the behavior of the chromosomes during cell division and how errors in this process can result in conditions such as Down syndrome. The case is presented in class using PowerPoint slides (~1.8 MB) that are punctuated by multiple-choice questions the students respond to using hand-held personal response systems (clickers).  It could be adapted for use without these technologies.


Objectives

  • Understand that DNA is stored on multiple chromosomes and that, during cell division, DNA is tightly compacted/packaged.
  • Explain that cells/organisms may have multiple, slightly different versions of the same chromosome referred to as homologous chromosomes. Cells that contain one copy of each chromosome are said to be haploid. Cells that contain two copies are diploid.
  • Describe what sister chromatids are and how they arise. DNA replication results in two identical copies of the same chromosome called sister chromatids. Sister chromatids remain physically connected together until near the end of cell division.
  • Describe the major steps of mitosis/meiosis and what processes occur in each step.
  • Draw a diagram and explain how the chromosomes behave during cell division and how this behavior differs between mitosis and meiosis.
  • Explain how cells can have too many or too few copies of a chromosome due to errors during division and chromosome segregation.
  • Understand that Down syndrome usually results from an extra copy of chromosome 21. (Partial copies can, though less frequently, result in the same syndrome.)
  • Explain how other syndromes associated with errors in chromosome segregation such as Turner (XO), Kleinfelter (XXY), and XYY syndromes as well as aneuploidy in many cancers may have occurred.
  • Describe how to use karyotypes to examine chromosomes in developing embryos.

Keywords

Mitosis; meiosis; chromosome; cell division; trisomy; Downs; Down syndrome; Kleinfelter; Turner syndrome; aneuploidy

Topical Areas

N/A

Educational Level

Undergraduate lower division

Format

PDF

Type / Methods

Clicker, Interrupted, Role-Play

Language

English

Subject Headings

Biology (General)  |   Cell Biology  |   Medicine (General)  |  


Date Posted

01/15/10

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