We thank our colleagues, students, and volunteers who spent countless hours using test versions of MEGA 3, 4, and 5 so they could provide valuable feedback pertaining to the ease-of-use of the user interface, incidences of software bugs, and appearances of documentation inconsistencies. Our testers' comments greatly influenced and improved all facets of the user interface and methodology implementations, and we are indebted to their service. The MEGA software project has been supported by research grants from the NIH, NSF, and Burroughs-Wellcome Fund to Sudhir Kumar, and from the NIH and NSF to Masatoshi Nei.