This compact review on a optical mapping is timely, because the technique is coming into increasing use due to the availability of automated platforms and of services at reasonable cost.

The manuscript is succinct and well written, and (unusually) I did not find need for revisions.

The manuscript does not go into the technical details of optical mapping, such as: - state of the art re the choice of nicking enzymes and potentiality for multiplexing - resolution limits based on the nicking enzymes available - DNA preparation issues for achieving long maps - practical limitations re accuracy of measured nick site spacing and implications for map assembly - software choices.

These would be useful for potential users of this technique.

However, dealing with these topics would greatly expand the manuscript; which appears to be about at the limit of 3000 words. Hence, I do not demand them as a condition for acceptance. Level of interest An article of importance in its field Quality of written English Acceptable Statistical review No, the manuscript does not need to be seen by a statistician. Declaration of competing interests I declare that I have no competing interests.