National Academies NorthStar Summer Institute for Undergraduate Science Education 2013 Heredity Team Title: X-inactivation and Gene Dosage Facilitators Kathy Miller, Washington University, St. Louis Victoria Corbin, University of Kansas Participants Alyson Zeamer, University of Texas at San Antonio Brenda Leady, University of Toledo Donald Auger, South Dakota State University Douglas Leaman, University of Toledo Lynn Riley, University of South Dakota Martha Lundell, University of Texas at San Antonio Background image: detail from Heredity by Regina Valluzzi

General Context Sophomore level genetics course Meets in an active learning classroom Regularly work in groups Routinely use clickers

Specific Context Relatively late in the semester Have discussed Mendelian genetics and the basics of gene regulation earlier in semester Have an understanding of aneuploidy

Learning GoalsLearning Outcomes Understand the relevance of X-inactivation Explain why neither XX nor XY results in a gene dosage disorder Suggest why sex chromosome aneuploidy causes abnormal phenotypes Enhanced understanding of gene dosage Predict differences in expression with and without X-inactivation Be able to interpret and analyze data Interpret graphs from the literature and draw conclusions Be able to work collaboratively Work as a team to generate hypotheses and predictions

Learning OutcomesAssessment Explain why neither XX or XY results in a gene dosage disorder 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 Formative: RTL Quiz (individual and group) Formative: Hypotheses; comparison of data to predictions Summative: 1-minute essay Formative: Draw predictions Formative: Compare group to peer and published work Formative: Compare group to peer work

Start of Mini Lecture

o Too little or too much gene expression can be detrimental to the development or health of an organism. o In organisms with sex chromosomes there is a difference in the copy number of genes on the sex chromosomes. o Dosage compensation equalizes gene expression. Dosage Compensation A%20Replication-122.htm

X-inactivation was proposed by Mary Lyon in 1961 Barr bodies Mary Lyon XX female cells a-to-z-blogging-challenge-2013-x.html Adapted from: sod-histology-exam-1-slide-review/deck/

Sex-linked anhidrotic ectodermal dysplasia (absence of sweat glands). Areas without sweat glands are shown in black. Female Mosaicism Figure adapted from:

If X inactivation works, should a XXY genotype cause a problem in humans? A.Yes B.No Clicker Question

XXY Syndrome (Klinefelter’s) o Occurs in ~1:1000 live male births o Effects include small testes and reduced fertility o In adults, characteristics vary widely and may include no visible symptoms o Increased incidence of health problems that typically affect females /baby-xxy-boys-should-not-be-said-to- have-klinefelters-syndrome/

Teaching tidbit

Why do you see XXY syndrome in Klinefelter’s patients if X-inactivation occurs? In your groups, develop at least 2 hypotheses to address this question. 10 min

Groups report out. 5 min

Guide them back to 2 major hypotheses 2 Hypotheses: 1: Some causative genes on the X chromosome escape X- inactivation 2: Expression of causative genes on the X chromosome occurs before X-inactivation early in development

Gene A Gene B

Groups report out by showing data on document projector 10 min

Gene A Gene B Subject to X-inactivationNOT subject to X-inactivation Embryo (pre-X inactivation) Adult (post-X inactivation) These are the predictions we hope the students will produce.

Experimental Testing of the Prediction (Werler et al. 2011) Subjects - Adult mice with following phenotypes: – XY – XX – XX Y * (model for Klinefelter’s) Examined gene expression (RNA) for multiple genes on the X chromosome in multiple tissues

Results from two different genes in adult mice In groups, discuss whether these data support either of your predictions, and how. ** p < 0.01 Gene 1 Gene 2 From Werler et al. 2011

Clicker Question What can you conclude from these data? a)Some genes on the X chromosome escape X- inactivation. b)Some genes on the X chromosome are only expressed during early development. ** p < 0.01 Gene 1Gene 2

What additional questions do you have about X-inactivation?

Molecular mechanisms of X-inactivation. How one X chromosome avoids inactivation. Counting mechanism(s)? Topics for next class:

One minute essay On your 3 X 5 card, write a few sentences proposing an explanation for the aneuploid disorders associated with 45, XO and 47, XXY.

End of Teachable Tidbit

Diversity o Featured a woman scientist o Diversity of human phenotypes o Variety of Bloom’s level o Individual and group class work o Variety of modalities – written, oral, video o Inclusive of people with red/green color blindness

Learning OutcomesAssessment Explain why neither XX or XY results in a gene dosage disorder 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 Formative: RTL Quiz (individual and group) Formative: Hypotheses; comparison of data to predictions Summative: 1-minute essay Formative: Draw predictions Formative: Compare group to peer and published work Formative: Compare group to peer work

Feedback Was our activity effective? Do you feel our goals, outcomes and assessments are aligned?

National Academies NorthStar Summer Institute for Undergraduate Science Education 2013 Heredity Team Robin Wright Facilitators Kathy Miller, Washington University, St. Louis Victoria Corbin, University of Kansas Background image: detail from Heredity by Regina Valluzzi ACKNOWLEDGEMENTS Ref for data presented in tidbit: Werler et al., Acta Pediatrica. 100: