Fig. 2. jaws is a mutation in the first Zn finger of Tc'Kr. (A) After repeated outcrossing of the jaws mutation (induced in a GA-1 background) with the SB wild-type strain, all adult beetles that were jaws mutant carriers are also heterozygous for polymorphisms at the Tc'Kr locus, indicating close linkage between the mutation and the polymorphism. The polymorphism `SB' represents a Tc'Kr 3'UTR sequence specific to the SB strain that can be detected as a 205 bp RFLP band. The polymorphism `Tiw' is specific to the Tc'Kr copy of the jaws-carrying chromosome and results in a 141 bp RFLP (this polymorphism originally had been identified in the Tiw-1 wild-type strain). Depicted is an agarose gel with 11 samples (of 80 total). As controls, AseI-digested DNA amplified from a SB animal (SB/SB), a Tiw-1 animal (Tiw/Tiw) and an animal that resulted from a cross between Tiw-1 and SB parents (SB/Tiw) are shown. (B) Tc'Kr gene structure; the four Zn fingers are shown as black boxes. (C) Sequence of the first Zn finger of Tc'Kr. In the jaws mutant, the 2nd histidine is altered to a tyrosine.