Nat. Biotechnol. 36, 287 (2018); published online 5 April 2018; corrected after print 15 May 2018

In the version of this article initially published, paragraphs 2 and 3, it was stated that Oxford Nanopore Technologies (ONT) “announced an early access program to make available the MinION—a device containing the Mycobacterium smegmatis porin A (MspA) nanopore. The following year, ONT launched its first commercial product containing 'flow cells' featuring >500 MspA pores in a lipid monolayer.” As ONT has never disclosed what pores the early-access MinION used, the references to MspA have been removed. In addition, since the company has never used lipids and its membrane material is a trade secret, the second sentence has also been corrected. In paragraph 4, sentence 1 “Today, ONT's MinION can process up to 450 bases of DNA per second. Read-lengths in excess of 800,000 bases (ultra-long reads) are being reported in different laboratories...” had several inaccuracies. The MinION processes 450 bases of DNA per second “per channel.” Rather than read-lengths in excess of “800,000 bases,” reports are of read-lengths in excess of “1.3 Mb.” In the paragraph preceding the penultimate paragraph, the sentence “ONT would do well to take a leaf from Pacific Biosciences, which has encouraged open-source software development for its platform” overlooked two contributions by ONT, and has been revised. The errors have been corrected in the HTML and PDF versions of the article.