Horizontal transfer of chromosomal DNA mediated by an integrative and conjugative element generates frequent localized recombination in Novosphingobium aromaticivorans.

Integrative and conjugative elements enable frequent chromosomal DNA recombination within Novosphingobium aromaticivorans, affecting about 10% of its genome.

• Why it matters: Understanding how bacteria exchange genetic material is crucial for grasping their evolution and adaptation, especially within species where high-identity DNA transfer is common but hard to detect.
• What they did: The study analyzed soil isolates of N. aromaticivorans and found that ICEs facilitate directional, efficient chromosomal recombination near the element, requiring a relaxase, but this process does not occur between different species.
• The result: This mechanism enhances intra-species adaptability and maintains species boundaries by limiting recombination to closely related strains, shaping bacterial evolution and diversity.