Refine the genome panel in the taxon aspect

[Daniel-Mietchen]

E.g. in https://tools.wmflabs.org/scholia/taxon/Q202864 , it currently yields nothing, even though several Zika virus genomes are in Wikidata https://tools.wmflabs.org/reasonator/?q=Q202864&lang=en .

There seem to be several problems here:

• the query assumes chromosomes, which of course does not fit with all organisms
• the query also assumes items about individual genes, which have different likelihoods to get indexed in Wikidata as compared to the respective genomes
• issues around how to model genomes on Wikidata in general.

[Daniel-Mietchen]

Pinging #290 to keep track of progress on the taxon aspect.

[egonw]

Making the chromosome field OPTIONAL is not enough. I do see proteins associated with one of the genomes, but not genes. The model of linking gene/protein to the Zika virus is complex, and indeed not currently supported.