Thomas Mailund's latest post on the mouse genome harks back to a recent point raised by Sandra Porter: When is a genome sequence actually completed? Mailund expresses his surprise at a new PLoS Biology paper that says that the mouse genome is now complete — he'd thought it already had been finished. "Oh well, in any case the distinction between a draft and complete genome sequence is a bit artificial anyway. It is really only a matter of degree," Mailund concludes.