Idea was that this could be a short opinion piece / overview article (not an Annual Review) with some novel ideas/synthesis. I jotted down some initial thoughts after conversations with David Anderson at Caltech in early 2015. Additional input from another connectomics/cell type person (e.g. Kording, Seung, Ascoli), someone specialising in quantitative approaches to speciation (e.g. Chris Jiggins or David Stern) or one of the people doing DropSeq type work would be interesting.