Species specific classes for genome, chromosomes, and their parts

[mbrush]

We are generating an ontology of reference chromosomes and their parts (arms, regions, bands) from the UCSC chromosome band data ( see dipper issue #42 ). It is expected that this ontology will grow to include bands from the genomes of other species. To organize these in the ontology, we may want to create species specific grouping classes at each of these levels (e.g. 'human genome', 'human chromosome', 'human chromosome arm', 'human chromosomal region', 'human chromosome band'). These will live in GENO, under their respective parent SO classes.