DART dSph targets are in colored triangles: Sextans(Green) Scl(Blue) Fnx (Red). Large symbols stand for the sample stars of this work, small ones stand for earlier works and publications (Hill et al., in prep.; Letarte et al. 2010; Frebel et al. 2010a; Aoki et al. 2009; Shetrone et al. 2001). Other symbols are squares (Ursa MajorII, Frebel et al. 2010b), triangles (Coma Berenices, Frebel et al. 2010b), diamonds (Draco, Shetrone et al. 2001; Fulbright et al. 2004; Cohen & Huang 2009), star (Boötes, Norris et al. 2010), cross (Carina, Shetrone et al. 2003; Koch et al. 2008a), and circle (Leo IV, Simon et al. 2010). All Milky Way halo stars from our comparison sample are considered (black dots) Cayrel et al. (2004); Honda et al. (2004); Aoki et al. (2005, 2007); Cohen et al. (2006, 2008); Lai et al. (2008). For the purpose of this figure, Venn et al. (2004)’s compilation was added at [Fe/H]  ≥ −2.5.