[Campbell Biology P.400] The text discusses both consensus sequences and sequence logos. Wha... | Practice Question

The text discusses both consensus sequences and sequence logos. What crucial information, provided by a sequence logo, is typically lost when only a consensus sequence is used?

  • A: The absolute number of sequences analyzed.
  • B: The specific nucleotide sequence.
  • C: The relative frequencies of all bases at a given position and the overall predictability of that position.
  • D: The presence of mutations.

Explanation

A consensus sequence only provides the most frequent base at each position and a dash if no clear majority , losing information about the relative proportions of other bases and how 'strong' the consensus is. A sequence logo, however, uses letter height to show relative frequencies and stack height to show overall predictability/information content, providing a much richer view of conservation and variation.