Version 7 contains a number of enhancements over MEGA6. They include
· Optimized source code for 64-bit processor architectures. MEGA can now utilize many GB of memory (depending on available hardware resources and operating system) whereas MEGA previously could only utilize < 4GB of RAM. (note*** MEGA7 and future versions will not be distributed for 32-bit architectures).
· Added a wizard-style system for identifying gene duplication events in a tree. Additionally, if a species tree is provided, speciation events will be identified using the algorithm of Zmasek and Eddy (2001).
· Re-factored the Tree Explorer so that trees with as many as 100k taxa can be displayed. This is dependent on the available memory and graphics processing resources.
· Re-factored the Timetree system for estimating relative and absolute times of divergence for all branching points in a phylogeny (Tamura et al. 2012) to use a more intuitive wizard-style interface.
· Updated the Tree Explorer to display data coverage at all internal nodes in an inferred tree. The data coverage values can be used to identify problematic nodes in the tree whose branch length estimates may be unreliable due to insufficient data coverage.
· The Timetree system now requires that all timetrees be rooted using an outgroup. The user interface has been updated with two methods for specifying the outgroup (via the Tree Explorer or via the Taxa/Groups dialog).
· Additional image formats have been added for exporting tree images.
· The dependency on ImageMagick has been removed.
· The Caption Expert system has been updated so that captions can be docked in the Tree Explorer window.
Version 7 also introduces a backwards incompatibility due to the refactoring for 64-bit processor architecture
· Session files (*.mas, *.mts, *mdsx) created in previous versions of MEGA cannot be opened in MEGA7 and will not be supported in future versions of MEGA either. Previous versions of MEGA are available for download from http://www.megasoftware.net/previousVersions.php and can be used to export data from older session files to .meg or .nwk files which can then be used in MEGA7 and beyond.