Actinomyces is a genus of Gram-positive bacteria that form branching filaments and are part of the normal oral flora. While generally commensal, some species can cause opportunistic infections, particularly actinomycosis, which affects soft tissues. Genomic DNA from Actinomyces is used to study its symbiotic and pathogenic roles in the human body. It serves as a reference for microbiome studies and helps in identifying genetic markers for diagnostic and therapeutic purposes.