There is only one file type that uses the .MEG extension:
MEGA Data File
Genetic data file used by MEGA, an application used for testing evolutionary hypotheses; saved in a plain text format and contains various kinds of genetic data and sequences, such as DNA codes or genetic distance data based on populations.
MEG files are used for performing genetic computations and for forming phylogenetic trees (.MTS files) for genetic relationship inferences.
NOTE: MEGA stands for Molecular Evolutionary Genetics Analysis.
Updated: August 16, 2015