Field of Science

Showing posts with label musings. Show all posts
Showing posts with label musings. Show all posts

"Just another ciliate" – importance of sexy descriptions

ResearchBlogging.orgThere are species descriptions, and then there are species descriptions. All too often, you come across a mention of some obscure but ridiculously cool-looking organism, with only a very scant description of what it looks like and what it does. Much less often, you can come across yet-another-new-species (usually of a ciliate), but a particularly nicely described one. Again, those super nice descriptions tend to be of ciliates, largely due to the likes of Wilhelm Foissner and his academic offspring. Descriptive detail can only make species more interesting, and eventually of great potential to be useful for science. (Conversely, many a taxon has been rendered invalid due to poor description)

A sexy description is also a great way to lure readers into noticing your otherwise garden variety new species. Case in point – I see this random IJSEM paper on a couple new marine ciliate Frontonia species – nothing too earth shattering. Being rather compulsive about skimming over any mention of a protist I see in the literature, I click. Being rather lazy and a shallow-minded picture-loving type, I head straight for the figures. Unexpectedly, they dazzle me with sexiness. Desperate for something easy to blog about for the next little while (impending interview, exams, end-of-term chaos, etc), I suddenly find your otherwise-routine new species description quite exciting and blog about it. Here, Frontonia mengi and F.magna get screentime largely thanks to their authors.

Some of us in science are that simple minded. If more people realised that and preyed upon our ilk with shiny pictures, think how much more presentable science as a whole would be!

(That said, no amount of gloss and shine can make your data more or less wrong. But it can, and does, dazzle some of us into overlooking a flaw or three...)

Actually, the above was just a long-winded elaborate excuse to post ciliate porn. Ah, check out the kineties on that ass!

Frontonia mengi. See text. (Fan et al. 2010 IJSEM)

Well, those were mostly just shots of its oral ciliature, but close enough. The root structures of the cilia are highlighted with silver nitrate and carbonate staining, yielding the pretty staining effect. a-c section through the 'mouth'; d shows the "membranelle" around the 'mouth'. e shows the area behind the mouth; arrowhead points to the cytopyge. 'Cytopyge'? Well, a cell's gotta get rid of its waste somehow, and ciliates actually have the cellular analogue of an asshole. Not the socially dysfunctional kind. So yeah, look at that ass. g shows detail of the cortex, h is the overall view of the ventral ciliature. At i, the rows of cilia "stitch together" at the 'anterior suture'. k shows the germline micronucleus (Mi) and somatic macronucleus (Ma).

Now for some delicious DIC:

Frontonia mengi. See text. (Fan et al. 2010 IJSEM)

Crisp DIC intoxicates me. The seductive allure of polarisation-derived faux-3D relief is nearly impossible to resist, especially when you have the fine complex cell of a ciliate. In fact, good DIC is often better than staining, since you don't have to fix (kill) anything. Unfortunately in the case of some larger ciliates, some degree of squishing must be done otherwise the sample is too damn thick for crisp DIC. I think the gist of microscopy can be summarised as the never-ending compromise between care of specimen and care of the optical setup. The most powerful microscopy generally requires total destruction of the specimen, whereas the most natural and undisturbed data can only be attained with simple techniques and weak optics. It's like the Heisenberg principle of microscopy: the more accurately you determine the state of your specimen, the more mangled your specimen gets.

I digress. In the above plate, a-e show general views of several individuals of F.mengi. Remember my rant a couple posts ago about the usefulness of depicting morphotypical (shape type) variation? I hope it is evident here how that can be useful. For example, if only figure a was published, one could be mislead to consider that large vacuole a characteristic feature of this particular ciliate species. The other four images, however, show that to be a feature of just that specimen instead (non-contractile vacuoles, in this case). Furthermore, the authors even invluded a table of morphometric data, measuring the body dimensions and some visible subcellular details (like numbers of kineties and nuclear size) of 23 individuals.

The arrow in 1b points to a contractile vacuole – one could just make out the channel leading to the cell's exterior for expelling its contents. f-g show sections of the mouth, live. h shows detail of the cell surface, the oral apparatus quite visible (as is the cytopyge). i details the cytopharyngeal rods, which are specialised structures this genus of ciliates employs to devour long strands of algae. The characteristically massive ciliate nuclei are visible in j – the arrow points to the macronucleus while the arrowhead points to the micronucleus. No staining necessary, fuck yah.

Frontonia, like many ciliates, is also armed and dangerous. The surface is loaded with extrusomes (k), which can fire leaving a trail, much like the cryptomonad ejectisomes (l). m and n show the contractile vacuole and its exit pore, respectively. The contractile vacuole is necessary for osmotic regulation, especially in freshwater species, and is somewhat analogous in function to our kidneys.

The second species, Frontonia magna, is also well-described. In these specimens, one can make out the algal filament and its constituents – particularly in b, e and f. Like F.menga, it's also loaded with extrusomes (h). I particularly like i, which shows the ciliature of the anterior suture. It's quite hawt.

Frontonia magna. See text. (Fan et al. 2010 IJSEM)

Of course, no description is properly complete (in my opinion) without drawings to accompany the micrographs. Drawings highlight the important features observed by the authors, and are useful in combining information gathered from multiple sections and imaging techniques in a convenient summary. Making an accessible visual summary of a huge pile of microscopy data is no easy task, and is very much an art.

Continuing with F.magna, a summarises the ventral view of a typical individual. b provides a sketch of the sutures, without the distracting detail. c shows the side view, along with the contractile vacuole. d shows the relative sizes and positions of the nuclei. e, again, emphasises variation – it shows the various ways a cell appears after overeating with algal filaments protruding all over the place. It's amazing how hard prey can try to make their predator look like an entirely new freaking domain of life, by stretching it out and colouring it in all sorts of funny ways. A similar phenomenon has been responsible for an entire mistaken genus, Ouramoeba, in the otherwise totally awesome Leidy 1874 work on amoebae. The algal prey is detailed in g, while h details the cilia around the oral apparatus.

Frontonia magna See text. (Fan et al. 2010 IJSEM)

Of course, no species description these days is complete without a healthy phylogeny, and Fan et al. got that covered too. I feel I've stolen more than enough figures already, so I'll just say their Frontonia spp. fit snugly within Peniculia, a group including the famous Paramecium, and the two species are sister to each other. There's also a composition of drawings from multiple sources for other members of this genus, so this paper is a nice current reference for Frontonia, if you ever wake up one morning needing one. Believe me, these cravings may strike at the oddest hour.

Anyway, I just thought these figures really deserve to see the light of day, and not just remain buried away in what will very soon be just the back issues of a microbial systematics journal. While some may look down on routine-seeming research like basic species descriptions for they do not provide a fancy high-level synthesis or anything, but ultimately, these fancy high-level syntheses are built on lower-ranking papers like these, and cannot exceed the quality of their constituents. It is primary 'basic' literature like this that forms the foundation of science; without species descriptions, without "yet another gene/genome/tree/whatever", there will be nothing to base the more glamorous studies on. This is why impact factor is a load of bullshit, and anyone whose hands itch to oppress "low impact" science should be kept the hell away from research funding strategies, for they obviously have no fucking clue how research works in the first place. Grrr. How can anyone vote against a species description as awesome as Fan et al. 2010 above?

Reference
Fan, X., Chen, X., Song, W., Al-Rasheid, K., & Warren, A. (2010). Two new marine Frontonia species, F. mengi spec. nov. and F. magna spec. nov. (Protozoa; Ciliophora), with notes on their phylogeny based on SSU rRNA gene sequence data INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY DOI: 10.1099/ijs.0.024794-0

Research proposal ramblings – Eukaryotic cellular evolution

Have a research proposal to do in a week for a graduate research fellowship (which also contributes to my spotty blogging as of late). Figured I'd try out Rosie's strategy of blogging to generate ideas and sort things out a bit. Would really appreciate feedback + discussion, particularly criticisms. This is my first time doing one of these, so I'm a total clueless n00b. This isn't my proposal, obviously, but rather a pre-draft of a pre-proposal draft, to lay out some thoughts ;-)

And this stuff needs to be narrowed down A. LOT. I'm well aware of that!

Topic: Eukaryotic cellular evolution
Or "cellular evo-devo"; of protists, obviously ;-)
Possible subtopics:
- The role of non-genomic ('cellular') inheritance in the broader context of evolution
- The relative extent of cellular inheritance in various unicellular and multicellular examples, in relation to size/"complexity", effective population size, mutation rates, whatever. (no idea how I'd do that yet though)
- Tracing the path of individual components in eukaryotic evolution, such as specific protein families, etc. Comparative work.
- ?

Background
Early evolutionary biology focused on the macroscopic level, such as general morphology of an organism and its behaviours in relation to its ecology. Later developments in molecular techniques have largely shifted the focus of the field towards the molecular scale, focusing on genes and proteins. In doing so, the organisms have been reduced to mere genomes – their cellular and developmental contexts largely forgotten. While evo-devo aims to revive the developmental aspect of evolution in multicellular organisms, little has been done to approach evolutionary biology on the level of individual cells, particularly in unicellular lifeforms. Cellular biology is crucial to a properly holistic understanding of evolution, and since the vast majority of organisms on earth, both in quantity and in diversity, are cells, time is ripe to investigate the role of extra-genomic cellular hereditary processes and their role in organismal evolution as a whole.

The first requirement of studying cellular evolution is good sampling. This demands a good phylogeny, and well-understood cell biology among non-Animal/Fungal/Plant organisms. Phylogeny together with cell biology must then be used in attempt to reconstruct ancestral states in order to seek out potential patterns and correlations. These patterns must arise several times independently, in order to have a decent independent sample size. However, at this point it's still only comparative biology; to make it to the level of evolutionary theory, predictive models must be inferred and tested from these patterns – this would ultimately require tying it in with the entire range of biological topics, from biochemistry to population genetics and ecology.

Of the above steps, only the phylogeny has begun to more-or-less solidify, at least enough to begin doing comparative work, if enough well-developed model systems exist in the attention-starved areas of the tree. However, the organismal & cell biology side does not fare as well: of the non-Animal/Fungal/Plant eukaryotes, only the medically important intracellular parasites like Plasmodium, Giardia and Trypanosomes have been well-studied (in the molecular cell biology sense), as well as cellular slime mould Dictyostelium due to its assumed significance in the evolution of multicellularity. To a lesser degree, ciliates Tetrahymena and Paramecium have been studied, as well as diatoms and oomycetes. This leaves huge swaths of phyla severely underrepresented, including practically all of Rhizaria. It must first be established whether anything is salvageable from what has been done to date.

(It would be unwise to rely on developing a novel model system for a PhD project, as potentially awesome as some candidate species may be. Maybe on the side, somehow (I really want Allogromia!))

As an aside, the close relatives of a potential model system should be examined to evaluate how well this model represents the group – picking at outrageously derived system would not be preferred for comparative work, although it would be quite biologically informative in its own right. Some of model candidates may have annoying quirks for certain types of things – eg. Paramecium undergoes autogamy every couple of weeks and destroys its somatic nucleus, thereby being ill-suited for molecular work.

To summarise, studying cellular evolution would require further development of protistan model systems, as well as extensive comparative work between them. Project could focus either on using what's already there for widescale comparative and theoretical work, or picking a single system and working on it specifically.

Relevant examples
- directed assembly of ciliate cytoskeletal elements (Grimes & Aufderheide 1991; Sonneborn & Beisson 1965 PNAS; Frankel 1989) A substantial body of work exists on the topic of ciliate development and how a chunk of the cytoskeletal organisation and morphogenesis seem to depend on non-genomic factors; eg the vertical transmission of a surgically inverted row of cilia independently of genomic inheritance. Furthermore, during encystation, hypotrich ciliates lose all basal bodies, and morphogenesis must happen anew. Some altered traits are lost after encystation, some are not. A mysterious 'organising centre' seems to exist in Oxytricha that determines defining features of the new morphology.

- endosymbiotic bacteria (eg. Görtz 2006 The Prokaryotes) of ciliates as a model for cytoplasmic inheritance of more tangible/quantifiable things.

- organellar inheritance, but that's been done to death already. Relative to above two cases, I mean! (before they kick me out of the lab for saying that...)

Potential projects
A lone tumbleweed rolls across the vast expanses of the chilling mind desert as the ruins of a derelict ghost town stand as a ghastly reminder of the Mind's complete and total absense. A slanted cracked wooden door of the saloon creaks softly in the winds of confusion, seemingly bemoaning the long-gone days of vibrant endless drinking...OH, THERE, I GOT IT! I need beer, the cause of and solution to all research problems!

- Continue the ciliate morphogenesis work of the 60's-80's. Look for general evolutionary principles, if feasible. [something specific goes here]

- Cytoplasmic inheritance of endosymbiotic bacteria and their genomes; effects of various things on that; comparing patterns between different [independent] clades? [something specific and intelligent goes here]

- mapping known cell biological traits onto modern eukaryotic phylogeny, look for patterns. Protein trees, for starters. Eg, Jékély and Cavalier-Smith type of work.

- ?

- lock self in a dark closet microscopy 'room', grab Allogromia or Stentor or Oxytricha or something, work on its molecular cellular biology, screw the whole broad research questions thing. Play with new protists on the side. Be a real hardcore protistologist. Shun everyone else. Damn, so bloody tempting...

Considering the cytoskeleton is the best part of the cell, and tubulin kicks actin's sorry little ass, my hands are seriously itching to do some in vivo fluoresent labelling on various cytoskeletal components in foram reticulopodia, and...well, that's a career right there. Especially when their microtubules grow 10x faster than those of any other eukaryote. (not sure how foram genomes go – could be a pain to work with)

But ciliates are cool too. And Warnowiid dinoflagellates with their awesome 'camera eyes', and radiolarians, and all these other things that aren't even culturable yet. Damn.

Broader impacts, justification
...heh. Should probably have something vaguely resembling a faint outline of a potential project before even considering these. Content first, embellishments after, even if the latter can appear to be more important at times.

---

Problem with cellular evolution at the moment is that we don't even have a decent grasp of cell biology yet, even in multicellular model divas like Arabidopsis and C.elegans. Not even getting into the phylogenetic sampling issues and lack of extant theoretical framework.

And we haven't even mentioned the prokaryotic cells yet. Yes, they have cell biology too, not just bags of biochemistry. No, most people haven't realised that yet, and/or don't care. Yes, we're fucked.

The very idea of cellular evolution almost looks impossible at the moment. So I really want to do it!

Ok, now sink your teeth in and demolish my very dream of making it in my foolish career choice. Start discussion. I need ideas. My mind is full of arcane protist taxa to think straight anymore (did you know Pseudospora was reported in 1905 to produce uniflagellate gametes? Did you care? Lookie, I'm soooo employable! Transferrable skills galore!)

Happy 150th, Origin!

Science is a rather peculiar activity. Upon solving a particular problem, many more scientific questions arise from that. There is no end -- any elucidation tends to result in more and more work to do. Which is why we'd be eternally employable, were it not for a rather anti-scientific attitude in the general public (partly our doing). To quote a nice tidbit from a protistology lecture: "People in science get famous for creating problems". An example that went along with that was the discovery of microbial life by van Leeuwenhoek -- with the help of a series of microscopes, he unlocked a Pandora's box worth of questions, eventually leading to the birth of a fairly major field -- microbiology. He created some serious problems: How could life exist on such a small scale? How many more microorganisms are there? Where do they live? What do they eat? How do they eat? and [much later] May microorganisms be in fact responsible for some human diseases? Leeuwenhoek discovered a whole new world, perhaps even the closest thing we'll have to aliens within our lifetimes.

150 years ago one has witnessed a milestone in the discovery of yet another alien world of questions, parts of which are luckily quite visible to the naked eye. While the microbial world remained hidden by barriers of scale, this world was perhaps hindered by a barrier in perspectives; after all, entering this world required, in the words of one of its critics, "a strange inversion of reasoning" (MacKenzie 1868 qtd in Dennett 2009). The mischievous creator of problems at this milestone was Charles Darwin. What is truly wonderful about evolutionary theory is its broad applicability throughout various corners of disciplines, from biology to linguistics to the humanities to engineering, computer sciences and beyond. Like a fractal, it is at some level so simple, yet upon further examination, there is no end to its complexity. Seldom do theories surface with such breadth and profundity.

Doubtlessly, The Origin was an important work, skillfully blending a breathtaking variety of naturalistic observations and Malthus' idea of natural selection to create a central, unifying theory adressing the origins and causes of the diverse living world. He established that heredity, variability and selection* were the key principles of an evolving system. Of course, there were problems, such as his rather primitive understanding of the mechanisms of heredity. But overall, it was a quite an important catalyst in the creation of a new world of questions: namely evolutionary biology, and eventually other applications of the theory. 150 years ago, this very day.

*Let's not get into THAT argument here...


However, perhaps we give Darwin a little too much credit, elevating him to something akin to a deity of evolutionary biology. Or at least some very powerful spirit. It almost feels as if evolutionary theory stopped in its tracks after Darwin. Thing is, ideas are seldom generated. They come from somewhere -- usually by being blended from other ideas (recombination, anyone?). He happened to listen to the right people, at the right place, at the right time. And was also a wonderful writer and populariser of his own ideas, which is key to spreading any idea. In fact, there was plenty of work done before him that was just waiting to be materialised into some foundational book. Read more about this in this level-headed approach to Darwin by John Wilkins at Evolving Thoughts.

Headlines such as "Darwin was wrong: Scientists find X" are particularly annoying. Ok, so what? Of course Darwin was wrong on most things, just like the rest of us! Especially since science has progressed a little in the last 150 years. Is it really headline-worthy material? Why don't we ever say "Wallace was wrong" or "Newton was wrong", by the way? And, on that note, why not "Psi was wrong"? =D Darwin is not the Holy Guardian of Evolutionary Theory! He missed a lot of things, mainly because he lived over a century ago! Besides, evolutionary biology has yet to be complete, and other applications of evolutionary theory are still young.

So what are some frontier areas of evolutionary questions? Of course there's still piles and piles of questions in biology - we barely understand a thing still. But it's happening. Now we have a decent idea of how characters may be inherited, at least genetic ones anyway. Cortical and cytoplasmic inheritance are still poorly understood, especially in fascinating cases like the heritable ciliary row inversion case in Paramecium (Beisson & Sonneborn 1965 PNAS, free access), where surgically altering cortical organisation results in it actually being inherited further and further, despite a lack of genomic alterations. The mechanisms behind this peculiar case are only beginning to be understood.

Another 'Wild West' of evolutionary thinking is in the humanities. Linguistics is an example of a particularly successful application of the theory, emphasised perhaps by the appearance of an evolutionary linguistics paper in Nature Rev. Genet. this summer. It's a pretty nice place to get a review in, thus evolutionary linguistics is finally accepted as a field, despite being practically banned until Pinker & Bloom 1990. Cultural evolution is a bit of a bigger warzone, although I think it too will follow the path of linguistics and find evolutionary modeling very useful and insightful. Unfortunately, many scholars in the humanities seem to have some rabid aversion to anything science related. To the point of quickly wrapping up the conversation and moving away upon finding out your affiliations. Linguists are much closer to the canonical 'natural' sciences (what is unnatural about language or culture or psychology is beyond me). Although even in linguistics they've got Chomsky, who viciously opposes any materialistic explanation of language and its origins, for reasons that seem to escape everyone. Don't get me started on Chomsky...

Incidently, I'm co-directing a student-directed seminar on the applications of evolutionary theory outside biology. It should be plenty of fun! It's a very exciting time for exploring these topics, for people are finally beginning to share wisdom between conventionally separated fields. One of these wisdoms that has great potential to deepen our understanding of the world around us, is evolutionary theory.

Anyway, here's to Darwin's Origin and all the subsequent developments in evolutionary theory! *toast*

Some more random links on the anniversary:
Darwin 200 Nature specials (may require subscription)

T. Ryan Gregory has a collection of 19th century Darwin caricatures over at Evolverzone. It's quite entertaining.

Greg Laden has a celebratory reflective post here.


By the way, this has been in my head all day: Happy Monkey!

Assorted musings on barcoding

Speaking of Guelph (see prev post), Paul Hebert, the Canadian barcode god (or so I'm told), gave a talk today about...well, barcoding life. Overall, it was a good talk, and I can see why he's in charge of a bunch of stuff -- his talks are quite convincing. At least he's convinced me not to automatically fear/resent barcoding. Not that anyone asked for my opinion on these matters, but this is my little corner of the internet so I'll ramble some thoughts about it. (yes, ramble. You've been warned.)

I have a few traditional taxonomist friends who have painted a pretty negative image of it for me; there's even a mycology grad student who does quite a bit of barcoding herself and has come to be quite skeptical of it. Furthermore, being fascinating by the biology of things rather than their mere existence, all those billions of species don't exist as far as I'm concerned until they've been actually studied. And no, 600bp of a conserved gene sequence does not qualify.

The value of being able to identify something in the field without having to look at the 'length of the spine on the 3rd tarsus', to [badly] paraphrase Hebert, is clearly there. His dream of a handheld barcoding device perhaps could be especially useful to people who actually do fieldwork (wait, there's biology outside the lab? WTF?), although how you can 'read' a DNA sequence sufficiently quickly still eludes me. Don't you still have to wait for crap to get amplified? Would be awesome if they have some way of doing really quick (and cheap) PCR, that could come in quite handy even for the model organism crowd. I don't necessarily enjoy waiting 2h to genotype some crap (oh, and another hour before that to extract gDNA). But I digress. This barcoding technology stuff does sound awesome.

However, I often have some skepticism towards awesome-sounding revolutionary technology -- too often people get carried away in the hype, and start attempting to use machinery to replace human intellect. That can be dangerous. Some tasks appear more mechanical than they really are, and it seems taxonomic identification and description is definitely among them. Most reasonable barcoding proponents don't seem to dismiss traditional taxonomy, but there is the fear that public opinion and funding agencies might not feel the same way. And as much as we love to reduce everything within our reach to digitised strings of characters, we still have to interact with the physical world.

Hopefully, the barcoding 'revolution' (that word is automatically associated with TC-S for me now, for some reason...) would be used in combination with the insight, knowledge and intelligence (ie talent) of traditional taxonomists, rather than attempting to replace them. Molecular phylogeny is substantially more reliable than anything morphology-based, as anyone who's wandered around in the protist kingdom would know*. But that doesn't mean morphological evolution is now to be ignored - on the contrary, molecular biology has made it much more exciting now that you could see how the organisms are related, and then investigate their morphology.

Another thing that annoys me is this whole 'species counting' business. You know, when someone spits out "There are 10 000 species of blah in blah", and the media picks up on it and we end up with "OMG, there are 20 000[sic] species of blah in [incorrect] blah!!!one! We are doomed/saved/awesome/cured of cancer[pick one]!" Seriously, who cares? Does it really matter whether there's 10 000 reproductively isolated clusters of something or 15 000 or 100 of them? Does counting them reveal anything profound? The majority of life on earth doesn't particularly care much about reproductive isolation! And among the few sorry exceptions where reproductive isolation becomes somewhat important (metazoa mostly; plants turn out to be a little more promiscuous), all species-counting can say is perhaps something interesting about...evolutionary dynamics of reproductive isolation. Furthermore, this ignores intraspecific variation, which is important and seemingly ignored by many evolutionary ecologists. And then we wonder why people get confused about where variation are. They see diversity as being composed of heavily discrete units, which may perhaps be confusing when trying to understand evolution itself.

That's not to say variation isn't important - it is, and it's definitely fascinating. But it does not do it much justice to simplify everything down to 'species', which then become treated as solid units of variation, rather than a subset thereof. It's far more complex than a mere absense of interbreeding.

Barcoding may be quite interesting for exploring how asexual vs. sexual (and facultatively sexual) organisms tend to cluster, how this clustering differs among various phyla, habitats, etc. Hebert did mention plans to pursue some of those directions, and it will be interesting to see what turns up.

Lastly, they seem to be using a single gene for barcoding. I think that's might even be what 'barcoding' would mean, strictly speaking. This is worrisome. Single gene phylogenies are CREEPY and SCARY o_O. I wouldn't touch one with a 10 foot pole anymore. Of course they picked something that [they think] is extremely conserved and constant (yet flexible enough to allow for variation at their desired resolution) - a commonly-shared mitochondrial gene (by the sound of it, Cox1 perhaps). They say it's conserved and reliable. Awesome - that's what they said about SSU rDNA. How did that turn out?

Bits of freaking FUNGI ended up as basal to all Eukaryotes, along with diplomonads, parabasalia and archamoebae, which have little to do with each other. Oh, and they still print this tree (which was quite a breakthrough at the time, to be fair; but things have changed in the last couple of decades...) Why? Some lineages experience faster rates of evolution than others, and this leads to much greater sequence divergence from its neighbours, which often screws things up in the alignment algorithms, resulting in Long Branch Attraction - things that diverged a shitload relative to everything else tend to cluster together. Some normally stable genes under certain circumstances can go haywire. Single gene trees a fucking dangerous. So are multigene trees, but we haven't got much else going for us...

Basically, the problems that plague SSU alignments can also fuck with barcoding. Especially once you wander outside the small comfy familiar home we call Metazoa...

Of course, everyone knows that, but I wouldn't be surprised if people suddenly started worshipping (and publishing) single gene trees based on barcode sequences. Faith in the scientific community seems to be inversely proportional to experience with it...

So yeah, it's exciting, but we must also be cautious. I guess that would be my [rather unhelpful] answer to pretty much everything...

Do you guys have any thoughts?

*Morphological classification led to almost all non-photosynthetic basal stramenopiles/heterokonts being mistaken for something considerably different: Labyrinthulids, oomycetes and Blastocystis were considered to be fungi, opalinids were 'ciliates', actinophryids were 'heliozoa', and there's even a genus called Pseudobodo (a bicosoecid) that was mistaken for...bodonids! Molecular phylogeny continues to churn out one surprise after another!