Well, this sounds like it's going to be real short… The ATG start codon determines the beginning of a gene! End of story, right? Maybe not so right. Rather than place your faith in what the textbooks say, try investigating the matter yourself, through computational experiments with your own fingers.

To do this, you'll need to bring up the following:

• CyanoBIKE (a version of BioBIKE devoted to cyanobacterial genomes)
   
• A tour called What is a Gene?
   
• A companion tour that leads you gently through the conventions of BioBIKE.