What is the role of primase in DNA replication?

DNA primase is a type of RNA polymerase. Since DNA polymerases can only recognize and elongate double-stranded sequences, the role of DNA primase in DNA replication is to catalyze and synthesize a short RNA segment (i.e., a primer) complementary to the ssDNA template, providing a double-stranded fragment for the DNA polymerase to recognize and thus initiating the replication. After elongation, the RNA piece will be removed by the 5’ to 3’ exonuclease and refilled with DNA. These DNA fragments are then joined together by DNA ligase, creating a single, continuous strand.