Figure 1

Interactive Python session showing a codon analysis of mammal nucleotide BRCA1 sequences. Line numbers are shown at the beginnings of input (but not output) lines and are referenced in the text. The terms '>>>' and '...' represent primary input and continuation prompts, respectively, from a Python interactive session. For noninteractive use, these characters and the following space are removed. The trailing '...' indicates additional output has been truncated.