Localized high divergence between TnRUNT and FrRUNT. This alignment between the first 171 bp of the predicted TnRUNT coding sequence, with the first 180 bp of FrRUNT, shows a cluster of mutations (curly brackets) around the N-terminus of the runt domain (gray background). Non-conservative mutations (negative BLOSUM scores) are surrounded with thick black frames; thin frames enclose conservative mutations, and synonymous mutations are not indicated. The first sixteen codons derive from exon 1, the rest of the alignment from exon 2. The secondary structures indicated (alpha helix, beta strands and loops) are after .