| 1965 to 1966 | Bowie, MD | 
| 1966 to 1968 | Leeds, England | 
| 1968 to 1972 | Bowie, MD | 
| 1972 to 1982 | Columbia, MD | 
| Fall 82 to Spring 88 | The University of Maryland at College Park. Undergraduate
Student.  Bachelor in Math in Spring 1988. | 
| Fall 88 to Fall 95 | The University of Maryland at College Park, Department
of Mathematics. Graduate Student.  PhD in Math in Fall 1995, in number theory and 
arithmetic geometry. | 
| Fall 94 to Spring 96 | The University of Pennsylvania, Department of Mathematics.
Visiting Graduate Student. | 
| Fall 96 to Spring 97   | Johns Hopkins University, Department of Mathematics.
Visiting Assistant Professor. | 
| Fall 98 to Jan. 2001 | University of Pennsylvania, Department of Biology
and the Computational Biology 
and Informatics Laboratory (CBIL) in 
the Penn Center 
for Bioinformatics (PCBI), Postdoc. | 
| Jan. 2001 to January 2006 | University of Pennsylvania, 
Computational Biology
and Informatics Laboratory (CBIL) in
the Penn Center
for Bioinformatics (PCBI), supported by NHGRI. | 
| 2007 to 2016 | Research Assistant Professor - Department of Genetics, University of Pennsylvania | 
| 2016 to present | Research Associate Professor - Department of Genetics, University of Pennsylvania | 
| 2013 to Present | Director of Bioinformatics ITMAT |