A gel cassette adaptor for use with an electrophoresis system gel cassette is disclosed herein. The gel cassette adaptor allows a single gel cassette to be compatible with more than one electrophoresis system. In one example embodiment, the gel cassette adaptor includes an open sided trough having an attachment perimeter and an attachment flange coupled to the attachment perimeter. The attachment flange is designed to be compatible for mating with a gel cassette that is compatible with a first electrophoresis system. After attachment of the gel cassette adaptor, the resulting gel cassette assembly is compatible with a second electrophoresis system. Also provided is a gel cassette that includes a stabilizer post that connects the cassette plates to maintain a constant gap width between the plates during electrophoresis. In reducing deformation of the gap space between plates during gel runs, the stabilizer post can improve electrophoresis results for wide format gels.