title: Calculating the expected frequencies of potential secondary structure in nucleic acids as a function of stem length, loop size, base composition and nearest-neighbor frequencies.
abstract: A formula is derived to estimate the expected frequency of potential secondary structure of a given stem length and loop size in a random sequence of nucleotides of known length and composition. An example is provided using the SV40 sequence which shows significant non-randomness in stem length but whose significance is reduced by more than six orders of magnitude by taking nearest neighbor frequencies into account.
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics*; D008433:Mathematics; D008722:Methods; D009690:Nucleic Acid Conformation; D013539:Simian virus 40 / Q000235:genetics
chemical_list: D004279:DNA, Viral