If there is one thing that bothers the ever-loving-shit out of YHN, it is when people make broad claims about "the evolution of eukaryotes", when they really mean "the evolution of animals", one of the least interesting branches of the Tree of Life from an evolutionary standpoint. Every time I hear someone say "And we looked at this phenomenon across all eukaryotes, from humans all the way to flies!" I want to stand up in their presentation and whip my fucking laptop at them. Maybe when I need to upgrade...
In presentations it just show the stupidity of the lab and the animocentrism that most people use to view the world. In print, however, it had to get through reviewers and the editor. So, when I got the feed from the most recent issue of Trends in Ecology and Evolution and clicked on the link for the paper by Schaack et al., I expected some interesting stuff. The title of the paper is, afterall, "Promiscuous DNA: horizontal transfer of transposable elements and why it matters for eukaryotic evolution". Sounds pretty cool, right? I like interesting eukaryote-wide phenomena that may have an impact of evolution of organisms. Isn't that what everyone reads to their kids at night?
But by the time I got through the first section, I knew this horse had blinders on and has galloping full speed to metazoatown. Ironically, the second paper they cite is a solid review by Keeling & Palmer on eukaryotic gene transfer which brings up several cases of movement of transposable elements among non-animal organisms (in fact they dedicate Box 4 to this very issue), but Sclaack et al only use this reference to state that gene transfer between eukeryotes "has remained more obscure" than that between prokaryotes. Um, true, but there is a shit-ton of data on the topic, much of it covered well in the Keeling and Palmer paper. It is usually a good idea to read more than the abstract when citing a paper.
In fact we know a LOT about the transfer of both genes and, to a lesser extent, non-coding DNA between eukaryotes. It happens often and if you search for the terms HGT or LGT and eukaryotes you get over 450 hits. Considering our understanding of this phenomenon has really emerged only as genome sequencing has expanded relatively recently, that's a decent number of papers.
But wait, PLS, you might say. The paper is about transposable elements, not all gene transfer! True, but not only has there been a significant amount of non-animal work done in this realm as well, the sheer number of genomes that have been sequenced from non-animal organisms in the last 5 years has yielded more than enough data to examine this question across eukaryotes. And no, throwing in one or two references from the land plant lit does not get one of the hook.
So why does such a small portion of an entire group continually serve in the eyes of many as a proxy for the whole? It is, IMO, just pure blind ignorance and unwillingness to think beyond the obvious. If I wrote an article claiming to have discovered a critical force for the evolution of vegetables and then only discussed a couple of examples from squash, do you think that would get reviewed well? How fast would I get reviews back blasting me for over-stating my evidence? Would it even get past the editor's desk?
If you haven't opened a biology textbook since the 1970's, consider this a head's up that the whole 3 kingdom 'animals, plants, fungi' (in that order of importance) classification is long dead and things are much more complicated these days. In fact, we know a tremendous amount about the world around us and how insignificant a contribution animals make to the diversity of organisms on the planet. Perhaps it is time to stop learning about biodiversity from the Discovery Channel and introduce yourself to the other 95% of eukaryotes.
Schaack, S., Gilbert, C., & Feschotte, C. (2010) Promiscuous DNA: horizontal transfer of transposable elements and why it matters for eukaryotic evolution. Trends Ecol. Evol. (25) 537-546.
Keeling, P., Palmer, J. (2008) Horizontal gene transfer in eukaryotic evolution. Nat. Rev. Genet. (9) 605-618.