The current definition of ‘gene’ is “a sequence region (or regions) that includes all of the sequence elements necessary to encode a functional transcript. A gene may include regulatory regions, transcribed regions and/or other functional sequence regions.”
Consider the following minor change:
"A region (or regions) that include all of the sequence elements facilitating the production of a functional transcript when encoded in the genome of some cell or virion. A gene may include sequence encoded in regulatory regions, transcribed regions and/or other functional sequence regions." This change, or some similar revision, would address the fact that all regions of a gene do not truly ‘encode’ the transcript derived from it, and that many parts of a gene (such as some enhancer regions) may not even be ‘necessary’ - ie it might only regulate or increase transcription.