Received: 14 May 2015
Accepted: 20 August 2015
First Online: 28 September 2015
Change Date: 18 December 2018
Change Type: Correction
Change Details: In the version of this article initially published, the y-axis numbering in Figure 1 was high by a factor of 10; the correct range is 0.5 to 2.5 million nonredundant genes. The error has been corrected in the HTML and PDF versions of the article.
: The authors declare no competing financial interests.