Greetings all, and welcome to The Mobilome, my new blog venture. I’ve been musing about creating a TE-devoted blog for a while now because they don’t seem to be well represented in the blogosphere. The goal of this blog is to spread the word about how cool TEs and other parasitic nucleic acids are by talking about interesting elements, papers both old and new and perhaps some educational posts about what TEs in general and why they are important to understand. I’m going to assume most people reading this blog, if any do, will be familiar with TEs so I won’t go into detail off the bat about TE basics.
I am T.E. and I find TEs fascinating. I’m a graduate student at the University of Guelph in Ontario, Canada where I’m doing my Masters. I’m co-supervised by Dr. Teresa Crease and Dr. Ryan Gregory and my project involves a type of TE called Pokey found in freshwater crustaceans called Daphnia, or water fleas. I might say more about my project in the future and I’ll certainly tell you more about Pokey and why I think it is one of the most interesting TEs you could choose to study for a number of reasons.
So what are TEs exactly you ask? TEs are selfish, mobile pieces of DNA that inhabit the genomes of both prokaryotes and eukaryotes like tiny little parasites. I’ll be covering the classic TEs like DNA transposons and retrotransposons but I also plan to write some posts on some more obscure or less popularized types of parasitic nucleic acids as well.
What about the blog title you ask? Mobilome is a word that was coined, I believe and correct me if I am wrong, in a paper by Frost et al. (2005) to describe the collection of mobile genetic elements which inhabit the genomes of eubacteria and archaebacteria. It was further fleshed out in a book chapter by Janet Siefert (2009) where the different constituents of the mobilome were outlined. I’m merely extending it to describe the mobile DNA found in all forms of life.
Check back soon J
Frost, L.S., R. Leplae, A.O. Summers, and A. Toussaint. 2005. Mobile genetic elements: the agents of open source evolution. Nature Reviews Microbiology 3: 722-732.
Siefert, J.L. 2009. Defining the Mobilome. In Horizontal Gene Transfer: Genomes in Flux (eds. M.B. Gogarten J.P. Gogarten J. Peter, and L.C. Olendzenski). Humana Press.
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I've heard that transposable elements can be used to determine how various species are related. A post on that might be useful :)
ReplyDeleteYeah, TE insertions have been used as phylogenetic markers a few times. I'll see what I can dig up about it.
ReplyDeleteBut, selfish? parasitic? Haven't those elements been for a long time an active part of evolution, by far... Are mitochondria also selfish or parasitic? What the hell are we?
ReplyDeleteGreetings for the blog from spain. Very interesting stuff!
I mean, they continue being, hopefully :)
ReplyDeleteWelcome to the blog :)
ReplyDeleteTEs can still be selfish DNA and contribute to the evolution of their host through insertions, recombination etc. TEs can cause mutations which generate variation in the host genome which can be acted upon by selection and drift at the host-level to cause evolution. What you don't need to do is to invoke host-level adaptive reasons for why TEs exist. They exist because they can and sometimes the mutations they cause can be beneficial, just like any other mutations.
Interestingly enough, some mitochondria can act selfishly. Certain mitochondrial genotypes will outcompete others and be passed on more frequently to offpring, sometimes at the cost of host fitness. I recently read Burt and Trivers book Genes in Conflict and they have several chapters about intracellular symbionts that trasmit selfishly. I highly recomend that book.
Absolutely not invoking adaptive reasons for TE's existence. It is just as you said, they are (just as endosymbiosis) a major source of variation at genomic level. We would not be here so easily without them... What I mean is that I consider them more globally, as an important part of the system, than individually as simply a selfish element... Thats an opinion. In reference to selfishness, thats also an interesting debate. Even our own cells can act selfishly, and sadly we can see it much more often than it would be desirable..
ReplyDeleteThank you for the book recomendation ;)