A 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. A gene is any 'gene allele' that produces a functional transcript (ie one capable of translation into a protein, or independent functioning as an RNA), when encoded in the genome of some cell or virion.

http://purl.obolibrary.org/obo/SO_0000704

A gene is any 'gene allele' that produces a functional transcript (ie one capable of translation into a protein, or independent functioning as an RNA), when encoded in the genome of some cell or virion.

A 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.

Regarding the distinction between a 'gene' and a 'gene allele': Every zebrafish genome contains a 'gene allele' for every zebrafish gene. Many will be 'wild-type' or at least functional gene alleles. But some may be alleles that are mutated or truncated so as to lack functionality. According to current SO criteria defining genes, a 'gene' no longer exists in the case of a non-functional or deleted variant. But the 'gene allele' does exist - and its extent is that of the remaining/altered sequence based on alignment with a reference gene. Even for completely deleted genes, an allele of the gene exists (and here is equivalent to the junction corresponding to the where gene would live based on a reference alignment).

gene

SO:0000704

gene

http://purl.obolibrary.org/obo/GENO_0000481