Luminosity–metallicity plot for BCGs (Kong & Cheng 2002; Shi et al. 2005), metal-poor galaxies from 2dF (Papaderos et al. 2006) and SDSS (Kniazev et al. 2003), our metal-poor galaxies, and four nearby GRB host galaxies (Stanek et al. 2006). Our sample of metal-poor galaxies fills in the region defined by the GRB hosts; all these galaxies have lower metallicity by ~0.5 dex than the Richer & McCall (1995) luminosity–metallicity relation (dashed line) for normal dwarf irregulars.