@nprofile1q... In DNA sequencing papers, it is now common to have 10+ authors, and by time the 1st round of reviews come back, those authors are scattered to the 4 winds
and contacting all the coauthors, much less getting them to sign off on changes made to accomadate reviewers, takes a long time
which, I would speculate, accounts for the sometimes *very long time it takes for a paper to get accepted