The chloroplast genome structure of the vascular plant Isoëtes is similar to that of the liverwort Marchantia

Restriction site mapping was used to characterize the chloroplast genome of the lycophyte, Isoëtes melanopoda. The Isoëtes chloroplast genome is approximately 139-145 kb in size with an inverted repeat of 12-13 kb. The gene content and consensus gene order are similar to that of Marchantia. A distinctive feature of the Isoëtes genome is an increased size of the small single copy (SSC) region possibly due to the insertion of a piece of DNA (3-8 kb) of unknown composition. The inferred insertion, along with a slightly larger inverted repeat, are responsible for the apparent size difference in the total genome relative to Marchantia. Patterns of restriction fragments were also consistent with the presence of a small inversion (2-3 kb) in the large single copy (LSC) region.