the command
{ >?Map_set Human; >Map; >Locus } $& { >?Map_set Mouse; >Map; >Locus }
does not work because of a problem in the parser of the query language
the parser breaks on ; evn though the ; is embedded inside a {}
sorry about that, it is a slghtly difficult problem needing one extra level
of recursivity in the system
i paln to do that someday, but with a rather low priority
jean