Globin mRNA species induced in B6SUtA cells by various chemical inducers analyzed by RNase protection assays. RNA samples prepared from nontreated and chemically induced B6SUtA cells were analyzed as described in Fig 3. Note that B6SUtA cells belonging to the single haplotype produced a 180-base–protected fragment of βh1 mRNA, shorter than that produced by Ba/F3 cells and 11.5-day-old DBA/2 mouse embryo blood as discussed in the text.