ABSTRACT
In earlier chapters we studied DNA sequences that were hundreds or thousands of bases in length. In this chapter, we’ll be studying sequences that are as small as four nucleotides long. The fine details of DNA sequence are important in defining key elements of gene structure. This chapter will describe examples where large collections of short sequences can create a consensus sequence, and small samples that reveal how variable nature can be. Some of the most exciting discoveries can be those where a sequence appears to “break the rules” and does not possess the usual signals for gene structure and expression.
