[Campbell Biology P.453] What is the primary function of the "spacer DNA" segments within th... | Practice Question

What is the primary function of the "spacer DNA" segments within the CRISPR region of a bacterial genome?

  • A: They act as recognition sequences for bacterial DNA replication.
  • B: They are palindromic repeats that regulate gene expression.
  • C: They are segments of DNA from previous phage infections, providing a "memory" for future defense.
  • D: They encode for Cas proteins, which degrade bacterial DNA.

Explanation

The text states that 'analysis by several research groups showed that each spacer sequence corresponded to DNA from a particular phage that had infected the cell.' This indicates that spacer DNA functions as a 'memory' of past infections, allowing the bacterium to recognize and defend against future attacks by the same phage.