What is episomal?

An episome is a type of genetic element that is capable of replicating independently of the host chromosome in bacteria and yeast. It contains one or more genes that can confer advantage to the host cell, such as antibiotic resistance or metabolic enzymes. Episomes can exist in two forms: integrated into the host chromosome (as a plasmid) or as a circular piece of DNA that floats freely in the cytoplasm. Episomes that are not integrated into the chromosome are often called extrachromosomal elements. These elements can be lost during cell division and may not always be passed on to the progeny cells. Episomes can also undergo vertical transmission, where they are passed from parent to offspring, or horizontal transmission, where they are transferred between cells through conjugation, transduction, or transformation.