According to a Scottish genealogy blogger, the US episodes of "Who Do You Think You Are?" will be aired on the UK's BBC after all US shows are screened.
Chris Paton, who writes Scottish Ancestry News and Events, reported on this earlier, indicating that the seven US episodes will be aired prior to the new UK 10-episode season.
He also notes that the US shows will be re-recorded by the narrator who does the UK show, and that some reorganization and editing will be done on each episode.
In any case, it means that 17 episodes will be running from late spring through the summer.
Paton also noted that another 25 episodes of Heir Hunters has been commissioned for BBC1 daytime television - those are set for winter 2010 or early in 2011.
For more information, read Chris' post (link above).