Center for Gene Regulation in Health and Disease (GRHD)

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.


  • Swetha
    Swetha Joswala
    PhD Student, 2014-Present
    SR 276
  • Abhishek Ganguly
    Abhishek Ganguly
    PhD Student, 2015-Present
    SR 276
  • Samhita Chaudhuri
    Samhita Chaudhuri
    PhD Rotation Student, 2016-Present
    SR 276
  • Kaveri Khanna
    Kaveri Khanna
    PhD Rotation Student, 2016-Present
    SR 276
  • Urja Patel
    Urja Patel
    Undergraduate Researcher, 2017-Present
    SR 276
  • Solomiya
    Solomiya Puschak
    Undergraduate Researcher, McNair Scholar, 2017-Present
    SR 276
  • Andrew Brandt photo
    Andrew Brandt
    Postbac Researcher, 2016-2017. Currently in Graduate Program in Biotechnology at Columbia University.
  • Dan Benchek
    MS Student, 2012-2016
  • Kyle Schroeder
    Undergraduate Researcher, 2014-2015. Currently in Medical School at St. George's University.
  • Valerie Sar-Shalom
    Valerie Sar-Shalom
    MS Student, 2015-2016
  • Elspeth Mitchell
    Elspeth Mitchell
    Postbacalaureate Researcher, 2013-2014. Currently in Vet School at Ohio State University
  • Rachel Winegar
    Rachel Winegar
    Undergraduate Researcher, 2013-2014. Currently in Podiatry School at Kent State University
  • Brendan Skrtic
    Undergraduate Researcher, 2013-2015
  • Liz Tracey
    MS Student, 2012-2014

Research Articles

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. PDF iconSeverson - 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. PDF iconSchvarzstein - 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. PDF iconSeverson - 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. PDF iconChan - 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. PDF iconSeverson - 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. PDF iconSeverson - 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. PDF iconHamill- 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. PDF iconSeverson - 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. PDF iconSwan - 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. PDF iconSeverson - 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.  PDF iconSeverson 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. PDF iconWood - 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. PDF iconSeverson - 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. PDF iconSeverson - 1999 - Current Biol.pdf