About Us


Our lab employs more than twenty staff including technologists, supervisors, directors, and trainees. Many of our staff have been working in the field of cytogenetics for 30+ years. Their institutional knowledge is priceless and we could not do what we do without them.



Vanessa Horner, PhD, FACMG

Associate Professor, Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison


Assistant Director

Xiangqiang Shao, PhD

Assistant Professor, Department of Pediatrics, University of Wisconsin-Madison



Eric B. Johnson, CG (ASCP), Cytogenetic Supervisor (Oncology)

Kim Oxendine, CG (ASCP), Cytogenetic Supervisor (Prenatal)

Richel Mayberry, MS, MT(ASCP) CGCM, MBCM, Molecular Genetics Supervisor

Leah Frater-Rubsam, PhD, Genomics Supervisor


Specialty staff

Yajing Peng, PhD, Genetics Research Specialist

Kimberly Anderson, MS CGC, Genetic Counselor

Maureen McCormack, MS, Laboratory Quality Assurance Specialist

April Meiller, Academic Program Manager

Lori Halverson, Medical Program Assistant


Cytogenetics/FISH team

Asma Ahmed

Erin Baldwin

Randee Blumer

Libby Cichy

Chris Corsi

Les Henderson

Beth Kositzke

Carol Miller

Lindsay Pettoruto

Danielle Pikard

Amber Walters

Fengli Zhang


Molecular team

Tracy Heidke

Eric Maas

Maureen Sullivan


LGG Training Fellows

Wuyan Chen, PhD

Hieu Nguyen, PhD

Morteza Seifi, PhD

Jessica Tumolo, PhD


Past Directors and Fellows