Giants within: a new class of microbial mobile elements.

Giant extrachromosomal elements over 1 Mb in size have been discovered in prokaryotes, revealing a new class of microbial mobile genetic elements.

• Why it matters: Understanding these large ECEs is crucial because they challenge existing classifications and could significantly impact our knowledge of microbial adaptation and gene transfer.
• What they did: Long-read sequencing enabled the identification and comparison of several giant ECEs, highlighting their diverse genetic structures and uncharacterized gene functions.
• The result: This discovery broadens the scope of microbial genetics, offering new insights into horizontal gene transfer and microbial evolution, and underscores the need for improved classification tools.