National Academies NorthStar Summer Institute for Undergraduate Science Education

1. 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 National Academies NorthStar Summer Institute for Undergraduate Science Education Background image: detail from Heredity by Regina Valluzzi

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

3. 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

4. Learning Goals Learning 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

5. Learning Outcomes Assessment Explain why neither XX or XY results in a gene dosage disorder Suggest why sex chromosome aneuploidy causes abnormal phenotypes Formative: RTL Quiz (individual and group) Formative: Hypotheses; comparison of data to predictions Summative: 1-minute essay Predict differences in expression with and without X-inactivation Formative: Draw predictions Interpret graphs from the literature and draw conclusions Formative: Compare group to peer and published work Work as a team to generate hypotheses and predictions Formative: Compare group to peer work

6. Start of Mini Lecture

7. Dosage Compensation • Too little or too much gene expression can be detrimental to the development or health of an organism. • In organisms with sex chromosomes there is a difference in the copy number of genes on the sex chromosomes. • Dosage compensation equalizes gene expression. http://home.btconnect.com/bordereta/DNA/Human%20DNA%20Replication-122.htm

8. X-inactivation was proposed by Mary Lyon in 1961 XX female cells Barr bodies Mary Lyon http://oaklawnimages.blogspot.com/2013/04/a-to-z-blogging-challenge-2013-x.html Adapted from: http://www.studyblue.com/notes/note/n/umkc-sod-histology-exam-1-slide-review/deck/3726390

9. http://www.hhmi.org/biointeractive/x-inactivation

10. Female Mosaicism Sex-linked anhidrotic ectodermal dysplasia (absence of sweat glands). Areas without sweat glands are shown in black. Figure adapted from: http://www.ncbi.nlm.nih.gov/books/NBK21977/

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

12. XXY Syndrome (Klinefelter’s) • Occurs in ~1:1000 live male births • Effects include small testes and reduced fertility • In adults, characteristics vary widely and may include no visible symptoms • Increased incidence of health problems that typically affect females http://xxytalks.wordpress.com/2013/05/22/baby-xxy-boys-should-not-be-said-to-have-klinefelters-syndrome/

13. Teaching tidbit

14. 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

15. Groups report out. 5 min

16. 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

17. Gene A Gene B Gene A Gene B

18. Groups report out by showing data on document projector 10 min

19. These are the predictions we hope the students will produce. Subject to X-inactivation NOT subject to X-inactivation Gene A Gene B Embryo (pre-X inactivation) Gene A Gene B Adult (post-X inactivation)

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

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

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

23. What additional questions do you have about X-inactivation?

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

25. 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.

26. End of Teachable Tidbit

27. Diversity • Featured a woman scientist • 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

28. Learning Outcomes Assessment Explain why neither XX or XY results in a gene dosage disorder Suggest why sex chromosome aneuploidy causes abnormal phenotypes Formative: RTL Quiz (individual and group) Formative: Hypotheses; comparison of data to predictions Summative: 1-minute essay Predict differences in expression with and without X-inactivation Formative: Draw predictions Interpret graphs from the literature and draw conclusions Formative: Compare group to peer and published work Work as a team to generate hypotheses and predictions Formative: Compare group to peer work

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

30. 2013 Heredity Team ACKNOWLEDGEMENTS Robin Wright Facilitators Kathy Miller, Washington University, St. Louis Victoria Corbin, University of Kansas National Academies NorthStar Summer Institute for Undergraduate Science Education Ref for data presented in tidbit: Werler et al., 2011. Acta Pediatrica. 100:855-891 Background image: detail from Heredity by Regina Valluzzi