Genomic islands in prokaryotes are areas of niche-differentiation where novel genes move in and out of the genome, sometimes with improvement in fitness of the host. Duplicated genes would be a separate means to evolve new or improved functions. These are two very different evolutionary scenarios under which a cell evolves.

Thank you for your thoughts. I'm working on wheat and the term gene island might be erroneously used by me. But many plant genomes have mosaic structure having high gene density regions and gene poor regions. I found some literature postulating the high gene density regions are co-expressed or functionally related. But it is not clear to me what to make of duplicated genes within this concept.

chandima