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I have a bit of free time, thought I'd write a smol thread on one of my fav organisms* not a fan of writing Twitter threads, also because my hand still hurts when I type too much. But I'm sure you'll love learning something new
*It's as unique as my name or I like to think so :P
*It's as unique as my name or I like to think so :P
Let's have a look at Salpingoeca rosetta; #marine species that forms rosette-shaped colonies 
It is a second choanoflagellate to have its genome fully sequenced (55 Megabases!) #protists #evobiology #scicommUU20 #scicomm #choanoflagellate https://twitter.com/davislaundon/status/781769111470608386
It is a second choanoflagellate to have its genome fully sequenced (55 Megabases!) #protists #evobiology #scicommUU20 #scicomm #choanoflagellate https://twitter.com/davislaundon/status/781769111470608386
What makes Saplingoeca rosetta fascinating: "S. rosetta can transition through at least five morphologically and behaviorally differentiated cell types" cell biology is an art! 
https://twitter.com/delCampoLab/status/1171811417520893952
https://twitter.com/delCampoLab/status/1171811417520893952
One reason I find it fascinating is its formation of multicellular colonies (single cell undergoing multiple rounds of incomplete cytokinesis) How does it happen? Check this https://elifesciences.org/articles/00013 (bacteria influencing biology of other species including us is..just so coool!)
In 2013, Fairclough et al analysed the genome and transcriptome of S. rosetta! (33x average coverage, 154 scaffolds, average N50: 1.52 Mb) & found that S. rosetta has a minimum of 33 chromosomes & contains over 11k genes (31% unique to S. rosetta) https://genomebiology.biomedcentral.com/articles/10.1186/gb-2013-14-2-r15
If all this choanoflagellate genomics is not awesome enough, study published this year showed that it is now possible to perform gene editing in S. rosetta. This makes it the first model choanoflagellate genome for #CRISPR/Cas9-mediated editing 
https://elifesciences.org/articles/56193
https://elifesciences.org/articles/56193
These studies are missing something! They jumped over (pun intended) the topic of Transposable Elements (TEs) xD jk *awkward pause* that’s what happens when *coughs* scientists are too busy studying TEs in multicellular species they forget about TEs in uniceullar relatives lol xD
Let's have a quick look at TEs in choanoflagellates! Until last year, there was only one published study that screened choanoflagellate genome for TEs - it found evidence of Long Terminal Retrotransposons (LTRs) in Monosiga brevicollis genome https://www.sciencedirect.com/science/article/abs/pii/S1434461008000357?via%3Dihub
It also briefly talks about another choanoflagellate species called Mylnosiga fluctuans, that turned out to have both LTR and non-LTR as well as DNA transposons in its genome.
What about TEs in Salpingoeca rosetta? Good news is that S. rosetta genome has both Class I (retrotransposon) and Class II (DNA transposon) elements Thanks to the study published last year! #choanoflagellate #protists #scicommUU20 #scicomm #genomics https://mobilednajournal.biomedcentral.com/articles/10.1186/s13100-019-0189-9
Thanks to the study published last year! #choanoflagellate #protists #scicommUU20 #scicomm #genomics https://mobilednajournal.biomedcentral.com/articles/10.1186/s13100-019-0189-9
The study found that the length of DNA transposon families in S. rosetta ranged from 2-8 kb & for LTRs, it's 4-11 kb. Another interesting found was that: as compared to most TEs with low copy number (<50), two of the elements appear to have >100 copies! those are copia-like LTRs
Last and my favourite part is horizontal transposon transfer 
this was very exciting to learn about! (especially when you are undergrad :D). The study shows one of the TEs, named SrosTm, have been transferred horizontally from stramenopile!! See Figure 2 in link I shared.
this was very exciting to learn about! (especially when you are undergrad :D). The study shows one of the TEs, named SrosTm, have been transferred horizontally from stramenopile!! See Figure 2 in link I shared.
Thanks to yours truly who worked on this; I analysed lots of phylogenetic trees to understand the evolution of TEs in S. rosetta and ended up discovering horizontal transfer (credit goes to my advisor though haha for being there for/with me). Team work makes research work haha
The first two parts of result section cover a lot more than this thread about TEs. So, have a look at the link I shared :) & also, for anyone interested in Transposable element expression and their patterns of codon usage, the paper is for you! :) Thank you & that's all 
