Dale Miller's academic genealogy

Dale Miller	Ph.D. Carnegie Mellon University 1983 Proofs in Higher-Order Logic
Peter Andrews	Ph.D. Princeton University 1964 A Transfinite Type Theory with Type Variables Recipient of the 2003 Herbrand Award for Advances in Automated Reasoning
Alonzo Church	Ph.D. Princeton University 1927 Alternatives to Zermelo's Assumption
Oswald Veblen	Ph.D. University of Chicago 1903 A System of Axioms for Geometry

At this point, a great many people trained in mathematics and computer science in the USA share this genealogy. The following list of ancestors was written by Dick Lipton on his blog.

Veblen, 1903, University at Chicago under Eliakim Moore.
Moore, 1885, Yale, under Hubert Newton. Here Moore is listed as having over 15,000 descendants-more than 1/10 of the entire tree-and Veblen has roughly half of them.
Newton only earned a BA. This is somewhat like being adopted. However, an advisor Michel Chasles is listed for the B.A., and the other descendants include the renowned mathematical physicist Josiah Gibbs.
Chasles, 1814, École Polytechnique under Siméon Poisson. Now we are in even more august company-Poisson's other doctoral students were Lejeune Dirichlet and Jospeh Liouville.
Poisson, 1800, also École Polytechnique, and another co-advisee: Joseph Lagrange and Pierre-Simon Laplace.
Going through Lagrange hits Leonhard Euler, while Laplace's advisor was Jean d'Alembert.