Dr. Aaron Severson

In all organisms, accurate transmission of the genome during cell division is essential to prevent genetic instability. This is especially true during meiosis, the process that reduces genome copy number, or ploidy, from two in diploid germline stem cells to one in each haploid gamete. Defects in meiosis affect all cells of an embryo and profoundly impact health: it is estimated that over 30% of human zygotes have abnormal chromosomal content at conception, and such aneuploidies are the leading known cause of miscarriages and birth defects. The best known viable aneuploidy, trisomy 21, causes Down syndrome. I use Caenorhabditis elegans to study how gametes inherit exactly one copy of every chromosome. Because the process of meiosis is widely conserved among eukaryotes, the meiotic mechanisms we identify in the lowly worm are relevant to understanding gametogenesis in humans.

Undergraduate Researcher, 2024-Present

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Volunteer, 2023-Present

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PhD Rotation Student, 2023-Present

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PhD Student, 2017-Present

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Previous Members

Undergraduate Researcher, 2023-24

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Undergraduate Researcher, 2023-24

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Undergraduate Honors Student, 2023-24. Subsequently attended Medical School at NEOMED.

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Undergraduate Honors Student, 2022-23. Subsequently attended MS-Anesthesia program at CWRU.

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Undergraduate Honors Student, 2022-23. Subsequently attended MS-PA program at Baldwin-Wallace.

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Undergraduate Researcher, 2022-23. Subsequently interned at Dermatology, Surgery & Cosmetics of NE OH

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Undergraduate Researcher, 2019. Subsequently received MS in Math from CSU.

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Swetha Joswala
PhD Student, 2014-20. Subsequently worked as Scientist I at Tessera Therapeutics, Somerville, MA

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MS Student, 2016-20. Subsequently worked as a Lab Technologist at Fulgent Genetics, Temple City, CA

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MS Student, 2017-2020. Subsequently worked as a Research Technologist at the Lerner Research Institute

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Undergraduate Researcher, 2017-19. Subsequently attended Podiatry School.

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Undergraduate Researcher, 2019. Subsequently worked as ASCP Med Tech at SW General Medical Center in Middleburg Heights, OH

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Undergraduate Researcher, McNair Scholar, 2017-18. Subsequently worked as a Patient Service Specialist at the Cleveland Clinic.

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Undergraduate Researcher, 2018. Subsequently, Algae & Zooplankton Taxonomist, Beachwood, OH

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College Credit Plus Researcher, 2018. Subsequently received BS-Pharmaceutical Sci from CSU.

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NIH/NIDDK STEP-UP High School Scholar, Summer 2018. Subsequently attended Columbia University.

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High School Student, Summer 2018. Subsequently attended NJIT/Rutgers Med School

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PhD Rotation Student, 2017

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PhD Rotation Student, 2016-17

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Postbac Researcher, 2016-17. Subsequently attended MS Program in Biotechnology at Columbia University.

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PhD Student, 2015-17

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MS Student, 2012-16

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Undergraduate Researcher, 2014-15. Subsequently attended Medical School at St. George's University.

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MS Student, 2015-16

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Postbacalaureate Researcher, 2013-14. Subsequently attended Vet School at Ohio State University

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Undergraduate Researcher, 2013-14. Subsequently attended Podiatry School at Kent State University

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Undergraduate Researcher, 2013-15

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MS Student, 2012-14

Research Articles

Turpin, C.G.S., D. Sloan, M. LaFores, L. Uehlein-Klebanow, D. Mitchell, A.F. Severson, and J.N. Bembenek. 2023. Securin regulates the spatiotemporal dynamics of separase. bioRxiv 2023.12.12.571338.  Turpin - 2023 - bioRxiv.pdf

Farboud, B., A.F. Severson, and B.J. Meyer. 2019. Strategies for efficient genome editing using CRISPRCas9. Genetics 211: 431-457.  Farboud - 2018 - Genetics.pdf

Hernandez, M.R., M.B. Davis, J. Jiang, E.A. Brouhard, A.F. Severson, and G. Csankovszki. 2018. Condensin I protects meiotic cohesin from WAPL-1 mediated removal. PLoS Genetics 14: e1007382.  Hernandez - 2018 - PLoS Genet.pdf

Severson, A.F., and B.J. Meyer. 2014. Divergent kleisin subunits of cohesin specify mechanisms to tether and release meiotic chromosomes. eLife 10.7554/eLife.03467.  Severson - 2014 - eLife.pdf

Schvarzstein, M., Pattabiraman, D., Libuda, D.E., Ramadugu, A., Tam, A., Martinez-Perez, E., Roelens, B., Zawadzki, K.A., Yokoo, R., Rosu, S., Severson, A.F., Meyer, B.J., Nabeshima, K., and A.M. Villeneuve. 2014. DNA helicase HIM-6/BLM both promotes MutSγ-dependent crossovers and antagonizes MutSγ-independent inter-homolog associations during Caenorhabditis elegans meiosis. Genetics, pii: genetics.114.161513.  Schvarzstein - 2014 - Genetics.pdf

Severson, A.F., L. Ling, V. van Zuylen, and B.J. Meyer. 2009. The axial element protein HTP-3 promotes cohesin loading and meiotic axis assembly in C. elegans to implement the meiotic program of chromosome segregation. Genes Dev. 23:1763-1778.  Severson - 2009 - Genes Dev.pdf

Chan, R.C.*, Severson, A.F.*, and B.J. Meyer. 2004. Condensin restructures chromosomes in preparation for meiotic divisions. J. Cell Biol. 167:613-625.  Chan - 2004 - J Cell Biol.pdf
* co-first author paper

Severson, A.F., and B. Bowerman. 2003. Myosin and the PAR proteins polarize microfilament-dependent forces that shape and position mitotic spindles in C. elegans. J. Cell Biol. 161:21-26.  Severson - 2003 - J Cell Biol.pdf

Severson, A.F., D.L. Baillie, and B. Bowerman. 2002. A Formin Homology protein and a Profilin are required for cytokinesis and Arp2/3-independent assembly of cortical microfilaments in C. elegans. Current Biol. 12:2066-2075.  Severson - 2002 - Current Biol.pdf

Hamill, D.R., A.F. Severson, J.C. Carter, and B. Bowerman. 2002. Centrosome maturation and mitotic spindle assembly in C. elegans require SPD-5, a protein with multiple coiled-coil domains. Dev. Cell 3:673-684.  Hamill- 2002 - Dev Cell.pdf

Severson, A.F., D.R. Hamill, J.C. Carter, J. Schumacher, and B. Bowerman. 2000. The Aurora-related Kinase AIR-2 recruits ZEN-4/CeMKLP1 to the mitotic spindle at metaphase and is required for cytokinesis. Curr. Biol. 10:1162-1171.  Severson - 2000 - Current Biol.pdf

Swan, K.A., A.F. Severson, J.C. Carter, P.R. Martin, H. Schnabel, R. Schnabel, and B. Bowerman. 1998. cyk-1: a C. elegans FH gene required for a late step in embryonic cytokinesis. J. Cell Sci. 111:2017-2027.  Swan - 1998 - J Cell Sci.pdf

Invited Review Articles and Book Chapters

Severson, A.F. 2016. Analysis of meiotic sister chromatid cohesion in Caenorhabditis elegans. Methods Mol. Biol. 1515:65-95.  Severson - 2016 - MiMB.pdf

Severson, A.F., G. von Dassow, and B. Bowerman. 2016. Oocyte meiotic spindle assembly and function. Curr. Top. Dev. Biol. 116:65-98.   Severson et al - 2016 - CTDB.pdf

Wood, A.J.*, A.F. Severson*, and B.J. Meyer. 2010. Condensin and cohesin complexity: the expanding repertoire of functions. Nat. Rev. Genet. 11:391-404.  Wood - 2010 - Nat Rev Genet.pdf
* co-first author paper

Severson, A.F. and B. Bowerman. 2002. Cytokinesis: closing in on the central spindle. Dev. Cell 2:4-6.  Severson - 2002 - Dev Cell.pdf

Bowerman, B. and A.F. Severson. 1999. Cell Division: Plant-like properties of animal cell cytokinesis. Curr. Biol. 9: R658-660.  Severson - 1999 - Current Biol.pdf