This information was taken from the Mathematics Genealogy Project.

• Me: William Edwin Clark, Ph.D. Tulane University, 1964.
• My Advisor: Alfred Hoblitzelle Clifford, Ph.D. California Institute of Technology 1933.
• Clifford's Advisor: Eric Temple Bell, Ph.D. Columbia University 1912
• Bell's Advisor: Frank Nelson Cole, Ph.D. Harvard University 1886.
• Cole's Advisor: C. Felix Klein, Ph.D. Rheinische Friedrich-Wilhelms- Universität Bonn 1868.
• Klein's Advisors: Rudolf Otto Sigismund Lipschitz, Ph.D. Universität Berlin 1853 and Julius Plücker, Ph.D. Universität Marburg 1823.
• Lipschitz' Advisor: Gustav Peter Lejeune Dirichlet.
• Dirichlet's Advisors: Simeon Denis Poisson and Jean-Baptiste Joseph Fourier.
• Advisor of both Fourier and Poisson: Joseph Louis Lagrange.
• Lagrange (1736-1813) apparently was self-taught and had no advisor.

Since I wrote the above more links have been added to the Mathematics Genealogy Project and I can now trace my ancestory back to Gauss himself.

For more information on some of the mathematicians listed above see:

The MacTutor History of Mathematics Archive. by John J. O'Connor and Edmund F. Robertson, St Andrews University, Scotland

The History of Mathematics by David R. Wilkins Trinity College, Dublin, Ireland