The completion of the euchromatic portion of the human genome sequence was announced in Nature at the end of October. But even with this achievement behind us, we are reluctant to rest on our laurels. What should be sequenced next? For the human genome, the debate is divided between those who advocate the sequencing of genomes from more individuals — to learn more about genomic variation — and those who would like to see the human genome finally completed, by sequencing the heterochromatic regions.
The question of what to sequence next also applies to the choice of organism. Should we sequence closely or distantly related species? The platypus, for example, is scheduled to have its genome sequenced soon — this sequence and comparative genomics studies might give us important insights into mammalian evolution. If the platypus sex-determination mechanism is anything to go by (see Highlight on page 884), its genome might reveal findings that could be as bizarre as the animal's phenotype.
