There are many programs in molecular evolution.
Pennsylvania State University has a large number of faculty
conducting research on population genetics and molecular
evolution. If you are interested in plants, you might
contact Drs. Jeff Palmer (Indiana University), Mike Clegg
(University of California at Riverside), Jeff Doyle (Cornell
University), Elizabeth Kellogg (Harvard University),
Elizabeth Zimmer (Smithosonian Institution), Kenneth Sytsma
(University of Wisconsin), and Richard Olmstead (University
of Colorado). If you are interested in animals you might
contact David Hillis (University of Texas), Michael Miyamoto
(University of Florida), Christine Simon (University of
Connecticut), Stephen R. Palumbi (University of Hawaii),
Maryellen Ruvolo (Harvard University), Rob DeSalle (American
Museum of Natural History), Morris Goodman (Wayne State
University), Wesley Brown (University of Michigan), John
Avise (University of Georgia), Charles Aquadro (Cornell
University), Wen-Hsiung Li (University of Texas at Houston),
Richard Lewontin (Harvard University), Jeff Powell (Yale
University), Margaret Riley (Yale University), Walter Fitch
(University of California at Irvine), James Lake (UCLA), and
me (Rodney Honeycutt, Texas A&M University).
I have left out many names. You might write directly to the
new Society of Molecular Evolution (Walter Fitch, editor;
Molecular Biology and Evolution) and see if there is a
membership list.
Good luck in selecting a program.