Final answer:
The statement that the spacer region between adjacent CRISPR sequences in bacteria is composed of virus genetic material is true. Spacer DNA comes from past viral infections and helps the bacteria recognize and defend against future attacks by similar viruses.
Step-by-step explanation:
The spacer region between adjacent CRISPR sequences in bacteria is indeed composed of virus genetic material. This statement is true. The CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) system is an adaptive immune system in bacteria and archaea that provides defense against invading phages (viruses that infect bacteria) and plasmids. The spacer DNA in the CRISPR array originates from previous encounters with phages or plasmids. These spacers act as a genetic memory that enables the bacteria to recognize and respond to future invasions by the same or similar viruses.
During a viral infection, fragments of the virus DNA are integrated into the CRISPR loci of the bacterial genome as new spacers. When the same virus tries to infect the bacterium again, the CRISPR system uses RNA molecules transcribed from these spacers to guide Cas proteins to the matching viral DNA and target it for cleavage, thereby protecting the bacterium from infection.