National Academies Northstar Institute for Undergraduate Education in Biology
Teachable Unit Framework
Title of Unit
Date and Approach for Unit
Development
Unit Developers & Contact
Information
Context
Abstract
Learning Goals &
Outcomes/Objectives
X-inactivation
Donald Auger, South Dakota State University
Brenda Leady, University of Toledo
Douglas Leaman, University of Toledo
Martha Lundell, University of Texas at San Antonio
Lynn Riley, University of South Dakota
Alyson Zeamer, University of Texas at San Antonio
1 lecture for a sophomore level genetics course. The expectation is this class meets in
an active learning classroom, regularly work in groups, and routinely use clickers. This
activity is set late in the semester after the students have discussed Mendelian genetics
and the basics of gene regulation. They should already have some understanding of
aneuploidy.
At this point in the semester, students in this sophomore level “Molecular Genetics”
course will have covered topics related to sex determination (XY Chromosome) and
basic gene regulation (positive and negative transcriptional regulation by transcription
factors). Students will read material before class that will help them brush up on sex
determination in mammals and other organisms, dosage compensation and the concept
of X-inactivation. A mini lecture will cover Mary Lyon’s discovery of X-inactivation
and information on Klinefelter’s syndrome. The students will then perform an in class
activity in which they hypothesize why there are phenotypes associated with this
disease, make predictions about gene dosage, and compare their predictions to
published data. Unit incorporates active learning principles including formative and
summative assessment, group work, active learning. The unit was designed to be
inclusive (variety of modalities, sensitivity to red-green colorblindness) and diverse
(women in science, range of human phenotypes).
Goal(s): what students will know,
Desired Outcome(s)/Objectives(s):
understand, and be able to do; includes
specific student behaviors or performances
content knowledge, attitudes, & skills
that will indicate they have successfully
(i.e. “understand natural selection;”
accomplished the goal(s)
“appreciate the role of biology in
society;” “think like a scientist”
Understand the relevance of XExplain why neither XX or XY results in a
inactivation
gene dosage disorder
Enhanced understanding of gene dosage.
Be able to interpret and analyze data.
Be able to work collaboratively.
Suggest why sex chromosome aneuploidy
causes abnormal phenotypes
Predict differences in expression with and
without X-inactivation
Interpret graphs from the literature and
draw conclusions
Work as a team to generate hypotheses and
predictions
National Academies Northstar Institute for Undergraduate Education in Biology
Teachable Unit Framework
Incorporation of Scientific Teaching Themes
Active Learning
How students will engage actively in learning the
concepts
Activities outside of class:
Reading assignment
Activities in class:
RLQ quiz – individual + group
Mini Lecture
 Dosage Compensation
 Mary Lyon
 If X inactivation works…?
 Clicker question
 XXY Syndrome
Activities during tidbit:
 Why do you see XXY syndrome in
Klinefelter’s patients if X-inactivation occurs?
o In your groups, develop at least 2
hypotheses.
o Groups report out.
 In the field, the 2 major hypotheses are…
o Some causative genes on the X
chromosome escape X-inactivation
 Expression of causative genes on the X
chromosome occurs before X-inactivation early
in development
 Students graph predictions as a group.
o See handout (see supplemental
material)
 Example predictions supplied
for instructor.
o Groups report out.
 Experimental testing of prediction
o Data from Werler et al. 2011
o In groups, discuss whether these data
support either of your predictions.
o Clicker question for results
 Class discussion
o Introduction of topics for next class
 One minute essay
Assessment
How teachers will measure
learning; how students will
self-evaluate learning
Pre-assessments:
 RLQ quiz
(formative)
During tidbit:
 Hypotheses;
comparison of data
to predictions
(formative)
 Draw predictions
(formative)
 Compare group to
peer and published
work (formative)
Post-tidbit assessments:
 1-minute essay
(summative)
Diversity
How the unit is designed to
include all participants
o
o
o
o
o
o
Featured women in science
Diversity of Human
phenotypes
Variety of Bloom’s level
Individual and group class
work
Variety of modalities –
written, oral, video
Inclusive of people with
Red/Green color blindness
National Academies Northstar Institute for Undergraduate Education in Biology
Teachable Unit Framework
Sample Presentation Plan (detailed schedule with approximate timing for unit)
Session 1
Preclass
Reading assignment from
text book.
Enter approx. class
time for learning
activity
preparatory
material
presentation
Mini-lecture
10 minutes
Enter approx. class
time for learning
activity #1
30 minutes
Enter approximate
time for additional
learning activities
and associated
class
Work/preparatory
materials
Enter approximate
time for postactivity summing up
or transition
10 minutes
Add additional activities information as needed for the unit.
National Academies Northstar Institute for Undergraduate Education in Biology
Teachable Unit Framework
Resources for Teaching the Unit
(other files and information needed/helpful to teach the unit, including files for papers from which original data for class
activities is taken, supporting information for the instructor, handouts, in class activities materials, assessments with answer
keys, homework assignments, etc.)
Werler, S., Poplinski, A., Gromoll, J., and Wistuba, J. 2011. Expression of selected genes escaping from X inactivation
in the 41, XXY mouse model for Klinefelter’s syndrome. Acta Paediatrica 100: 885-891.
 Source of figure for data interpretation
HHMI video on X-inactivation http://www.hhmi.org/biointeractive/x-inactivation
Summary of Origin of the Idea
(How did you come up with this idea? Where did you get the inspiration?)
The source of the idea was a brainstorming session on difficult topics to teach involving heredity. We considered many
topics but X inactivation had both a clear “hook” into student emotions/ interests with Klinefelter’s syndrome and could be
used for a data interpretation/ analysis activity.
Effectiveness of unit components (if you have used it or part of it in your own teaching)
Summary of Feedback
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It was suggested to add a manipulative of yarn X chromosomes to show X-inactivation. Stickers could be added to
indicate a gene on the inactivated X or not for calculating gene dosage. This manipulative would be a valuable extension
freshman level course.
The photo of XXY individuals was a source of discussion. It may be considered overly graphic and dehumanizing. An
alternative photo of fully clothed individuals might indicate the range of phenotypes in XXY individuals. On the other
hand, the photo was a typical clinical representation of patient phenotypes. We leave this choice up to the individual
instructor’s discretion.
Many comments indicated that the tie to Klinefelter’s syndrome was effective in grabbing student attention.
Graphing of predictions may be more successful individually and then as group work.
Table of four graphs was well received in general. We do want to make sure that an instructor points out the two
different genes (X-inactivated or not) and in two different times (embryo or adult).
The hypothesis prediction graphs have been changed in the final upload to gene A and Gene B to avoid confusion with
the sample data analysis Gene 1 and Gene 2.
Summative 3x5 notecard seems too small for the size of the essay. We wanted to emphasize a short, succinct summary
of what students covered in class. A more extensive summary would follow the completion of the unit.
Acknowledgements
We would like to acknowledge our facilitators for their assistance in developing this activity.
 Kathy Miller, Washington University, St. Louis
National Academies Northstar Institute for Undergraduate Education in Biology
Teachable Unit Framework

Victoria Corbin, University of Kansas