I'm not an expert, but this seems like an area of debate. See a reply to that article: http://www.pnas.org/content/113/45/E6908 http://www.pnas.org/content/113

I'm not an expert, but this seems like an area of debate. See a reply to that article: http://www.pnas.org/content/113/45/E6908 http://www.pnas.org/content/113/45/E6908