The transgene insert consists of 8 kb sequence from BAC RP23-366H17 where an nls-lacZ beta-galactosidase reporter gene cassette was inserted after the Tbx3 translation start site. The fragment runs from a Sca1 restriction site 6 kb upstream to a PshA1 site at 2 kb downstream of the Tbx3 translation start site. (J:164751)