Welcome everybody! I’m glad you found us here at the second stop of the traveling MolBio carnival. If you’ve got an eye for the small and tiny you have arrived at the right address, as our rides and bazaars are specialized in molecular and cellular biology! I’ll be happy guide you along the carnival [...]]]>

Welcome everybody! I’m glad you found us here at the second stop of the traveling MolBio carnival. If you’ve got an eye for the small and tiny you have arrived at the right address, as our rides and bazaars are specialized in molecular and cellular biology! I’ll be happy guide you along the carnival grounds and show you all the great contributors.

Getting there
No point in organizing a carnival without means of getting there! These contributions are about cellular spaces and molecular localization and trafficking within the cell.

Lab Rat discusses the problems of getting proteins to the outer membrane of bacteria and folding them properly among the way. To cross all the obstacles the proteins encounter along the way, they are guided by the BAM chaperone protein. Interestingly, BAM itself is chaperoned by Skp! This Skp can be turned on and off, giving bacteria the power to decide when and where proteins are shuttled to the outer membrane.

An anonymous contributor on the ‘You’d Prefer an Argonaute’ blog discusses a paper on microRNAs. The main question addressed in this paper is whether these miRNAs can be delivered to other cells in small vesicles. While the researchers indeed find miRNAs in these vesicles, the author of the blogposts suggest other experiments and controls that should reveal the truth about this new mechanism.

Grant Jacobs from Code for life has submitted a great primer on the coiling of bacterial DNA. Being small, bacteria have to be smart about their space. DNA is not excluded from this principle, since unstretched the entire thread of DNA would be orders of magnitude larger than the bacteria itself! Bacteria use special proteins to compact the DNA and recent research has uncovered how these proteins form a continuous scaffold to which the DNA can associate.

In for the thrill
In this section of the carnival grounds, you’ll find thrill rides that are not for the faint of heart. in here you’ll find posts on extreme colds, the highest altitudes and zombie enzymes to statisfy your need for adrenaline and thrills.

In a guest post on MolBio Research Highlights, Cristopher Dieni blogs about what keeps the wood frog warm during the freezing winter nights. It turns out that the humble glucose molecule plays a central role in the cryoprotection of these amphibians. Since the blogpost is written by a scientist on his own work, it contains nice peeks behind the curtains of the research process. If you want to know some of the considerations and afterthoughts and work go into, go check it out!

Michael Clarkson brings in a sinister chill over the carnival grounds by discussing zombie enzymes on his blog. Mutations that were thought to ‘kill’ certain HIV enzymes, only impair the enzyme’s activity! If you only check if the enzymes bind their substrate they could appear dead, while they still have catalyzing activity. Michael contributed to the research himself and rightly warns that our understanding of protein mutations is based on a few examples from fewer species, so the right assays are required to see if the enzyme is truly dead.

Torah Kachur contributes a post from far-away Tibet! Unlike the Tibetans, Torah was struggling with the low oxygen in the mountainous country. Tibetan people have some adaptations that allow them to live at high altitudes. Read the blogpost if you want to know more about one of the genes that allows Tibetans to cope with one of the harshest environments on this planet!

Carnival hubbub
The noisy bazaars on the carnival grounds fill the air with chatter and shouting. These posts are all about the noise and chaos that is intrinsic to life, and the ways life has found to reduce some of that noise.

On the It Takes Thirty blog, Becky Ward blogs about two different signalling circuits that have something in common: they weren’t doing what scientists expected them to do. Instead of a linear relationship between the input and ouput, the circuits responded to fold changes. Signalling by fold change guarantees the reliability and consistency of the developmental pathways by making the whole system is more robust to noise. For the whole story, check out the entire blogpost!

Iddo Friedberg from Byte Size Biology pumps up the volume with the finding that bacteria are incredibly noisy! While they don’t actually make much sound, they’re incredibly noisy in terms of protein production and gene expression. Additionally, they discovered that mRNA and protein expression levels don’t correlate at all. But somehow, atop of all that noise, ordered systems arise, suggesting that there are other noise reducing or amplifying mechanisms that still need to be discovered.

The second blogpost contributed by Becky Ward has everything to do with signalling pathways and noise reduction. The subject of this post is the Notch pathway, which plays a major role in determining the destiny of cells during embryonal development (“You’ll be a nerve cell. And you there hiding in that corner, you’re a endothelial cell from now on!”). The ligand of Notch, Delta, can behave in two very different ways to Notch signalling. This makes the whole system a kind of phenotypic switch!

Signalling
The hawkers and peddlers try to attract your attention with varying visual and auditory signals. These blogposts are about the signals within our cells and on top of their genes that make us into who whe are.

Sally Church discusses the darker side of Notch signalling by highlighting the role it could play in proliferating cancers. Notch might be partly responsible for angiogenesis, or the growth of new blood vessels in a malignant tumour. The good news is that in mouse models, a combination treatment of standard drugs and drugs that reduce Notch activity were more effective than either drug treatment would have been alone. Read all about it here!

A blogpost on epigenetic inheritance appeared on Phased, by Michael Scott Long. Epigenetics is an exciting field of science that studies the modifications of DNA that come and go (‘on top’ of the normal genome, hence ‘epi’-genetics), and which are sometimes inherited. Long discusses a new piece of software to analyze these epigenetic modifications, to hopefully shed some light on the role of epigenetics in health and disease.

That’s it for this month’s edition of The MolBio Carnival. You can check future hosts and past editions on the Carnival’s home page. Be sure to subscribe to the RSS feed to receive notifications and summaries when new editions of the Carnival are posted. Also, you are welcomed to submit your best molbio blog articles to the next edition of The MolBio Carnival which will be hosted by Alexander Knoll over at Alles was lebt. More info here!

In the meantime, enjoy the carnival and beware of zombie enzymes!

Bosco DA, Eisenmesser EZ, Clarkson MW, Wolf-Watz M, Labeikovsky W, Millet O, & Kern D (2010). Dissecting the Microscopic Steps of the Cyclophilin A Enzymatic Cycle on the Biological Substrate HIV Capsid by NMR. Journal of molecular biology PMID: 20708627

Goentoro L, & Kirschner MW (2009). Evidence that fold-change, and not absolute level, of beta-catenin dictates Wnt signaling. Molecular cell, 36 (5), 872-84 PMID: 20005849

Such festive times! I just came back from a festival, to announce the arrival of a carnival!

The Carnival

The carnival in question is the The MolBio Carnival, which will be hosted here at Thoughtomics in two weeks. The carnival was set up a month ago by Alejandro Montenegro, Lab Rat, Psi Wavefunction, Alexander [...]]]>

Such festive times! I just came back from a festival, to announce the arrival of a carnival!

The Carnival

The carnival in question is the The MolBio Carnival, which will be hosted here at Thoughtomics in two weeks. The carnival was set up a month ago by Alejandro Montenegro, Lab Rat, Psi Wavefunction, Alexander Knoll and myself to give exposure to all bloggers who write about research on molecular and cellular biology. You can check out the first edition of the MolBio Carnival here.

If you’ve written a blogpost yourself on the subject of molecular or cellular biology, I encourage you to submit your posts to the blog carnival online here! All blog posts on biochemistry, microbiology, structural biology, signal transduction, gene expression etc.  are very much welcomed!

A blog carnival is a great way of exposing a larger and interested audience to your writing, so spread the word via social media, e-mails and general gossip on the streets!

The Festival

The festival that I would recommend to everybody is the Dutch Lowlands festival. Four days of great music, dancing, creativity, sweating, some more dancing, delicious food and general awesomeness. On Lowlands, a thousand little things happen besides the music. Street performers show off their talents and weirdness, while a philosopher is giving a lecture on the interface between humans and technology and twentysomething people are collectively jumping a rope made of duct tape.

Weirdness all around. Practical if you want to keep out an eye on your fish though!

Musical highlight? Miike Snow, no doubt about it.

Everyone knows Spider-Man’s main (and only?) talent is shooting sticky liquid from his “web-shooters”. Often his webs take the form of a rope that is perfect [...]]]>

Like a spider web, the evolution of spider silk proteins looks pretty complex. New research sheds some light on the evolution of these stretchy, sticky and tough proteins.

Everyone knows Spider-Man’s main (and only?) talent is shooting sticky liquid from his “web-shooters”. Often his webs take the form of a rope that is perfect for swinging through the streets of New York, but they can also be shaped like a net, amorphous globs or whip-like strands. The silk that real spiders weave is just as versatile. Depending on the application, it can have different mechanical properties. The silk they produce can range from sticky and stretchy threads for capturing prey to tough strands that form the web’s outer rim, or even aerial nets to capture flying prey!

Both spiders and Spider-Man can weave silk with different properties. Deinopis can weave nets and cast them to capture aerial prey!Source.

Spider silk is made of proteins called ‘spidroins’. Spidroins are huge proteins (> 3000 amino acids) and contain large stretches of repeated amino acids. Small amino acids like alanine, glycine and serine are repeated almost endlessly. The spidroins to fold into regular and tight structures thanks to this repetition. By mixing and matching different repeating ‘blocks’, the silk will get different properties.

The tight interactions between repeatable stretches give spider silk its mechanical properties. Source.

The repeating amino acids also cause major headaches for spider researchers everywhere, since the enzymes that are used for sequencing DNA get confused in the face of so much repetition. What’s more, since many spidroins evolved by the scrambling and rearrangement of entire repeated blocks, it’s very difficult to determine the course of spider silk evolution (scientists depend on steadily accumulating changes to reconstruct what happened in evolutionary history). If you consider that the earliest silk spinning spiders started diverging as much as 300 million years ago and that many silk proteins were duplicated and scrambled again, you’ve got a clear picture on how difficult the puzzle that is called spider silk evolution really is.

Luckily, the regions that flank the repeated region (the C-terminus and N-terminus) are evolving more steadily, making them more useful for figuring out what happened in spider silk evolution. So far, the C-terminus has always been used in these kind phylogenetic analyses because it is easier to sequence. But Jessica Garb and colleagues decided to also sequence and analyze the N-termini of many spidroins, since it is around 50% bigger^*. You can find the the inferred phylogeny of the spidroins below.

Bayesian spidroin phylogeny. Inferred gene duplications are black circles on the branches, coloured crosses are inferred losses motifs and coloured squiggly lines are inferred gains.

The evolution of spider spidroins seems to be mainly associated with the evolution of their associated silk glands. As you can see in the tree above, the TuSp1, Flag and MiSp spidroins which are all expressed in separate glands cluster together. An exception are the MaSp spidroins, which are sprinkled all over the tree (top, middle and bottom). The authors suggest that several rounds of duplication and loss of a certain gland type could lead us to believe that while both gland and silk look similar to us, they’re actually not homologous (related by common descent).

The team also reports the discovery of an N-terminal domain in the group of Mygalomorphea (tarantulas and such) that has high sequenc similarity to N-terminal domains in the Areanomorphea (your garden spider). At the latest, these groups of spiders diverged 240 million years ago, indicating that the silk that spiders weave now is similar to the first silk that was first spun in the Triassic, a time when the earliest crocodiles and turtles started walking this earth!

Spiders: spinning silk since 240 Mya BC.

If you want to read more on transgenic silk production in silk worms and goat milk (!), check out this blogpost by Christina Agapakis on the Oscillator.

^* While the inclusion of the N-termini in the analysis did not generate significantly different trees, the resolution with which some difficult branches could be resolved increased.

Scientists from the University of Halifax in Nova Scotia, Canada have discovered photosynthetic algae living inside embryonic cells of the spotted salamander, providing them with extra power like a mean green energy drink. If true, this is the first known example of a vertebrate acquiring a new symbiont.

The spotted salamander [...]]]>

Scientists from the University of Halifax in Nova Scotia, Canada have discovered photosynthetic algae living inside embryonic cells of the spotted salamander, providing them with extra power like a mean green energy drink. If true, this is the first known example of a vertebrate acquiring a new symbiont.

The spotted salamander is a salamander species endemic to North America. It lays eggs that are encapsulated in a thick layer of jelly. While this jelly protects the egg cells from predators and dehydration, it also makes it more difficult for oxygen to reach the innermost embryos and for carbon dioxide to dissipate. The embryo could die if these gases are exchanged too slowly. Luckily the salamander embryos receive help from algae that can be found within the salamander eggs. Since algae produce oxygen and take up carbon by photosynthesis, they are a perfect match with the growing embryos that struggle with their oxygen supply.

Close up of a single egg cell containing a salamander embryo and numerous algae growing within the egg. Source.

The symbiotic relationship between the single-celled algae Oophila amblystomatis and the spotted salamander has long been known. Its first appearance in scientific literature can be traced back to a publication by Henry Orr in 1888. He wrote:

I have not discovered how the Algae enter the membrane, nor what physiological effect they have on the respiration of the embryo, but it seems probable that in this latter respect they may have an important influence.
~ Henry Orr, Quart. Jour. Micr. Sci., N.S. 29: 295-324.

This observation turned out to be spot-on when Gilbert showed in 1944 that salamander eggs without algae hatched less often and produced developmentally retarded larvae. The algae also benefit from this relationship, as they receive nitrogen rich wastes from the developing embryo. They have never been observed outside of amphibian eggs. They thus appear to be just as dependent on the salamander embryos as they are on them. The name of this algal species (Oophila amblystomatis) couldn’t be more appropriate: it literally means “loves salamander eggs”.

Now, 122 years after the first discovery of this symbiosis, Ryan Kerney of Halifax University has shown that the embryonic salamander cells themselves contain algal symbionts. The first clue he received was that the salamander cells fluoresced in the dark, without any sort of staining. This hinted at the presence of chlorophyll, which is auto-fluorescent.

The Spotted Salamander: the happy host of the Oophila algal symbiont! Source.

Closer inspection with electron microscopy revealed that the algal symbionts really were located inside the cells. They were surrounded by mitochondria, the power plants of the cell. This suggests that the algae are directly fueling the mitochondria with oxygen and carbohydrates. Even cooler, Kerney also found the algae in the oviducts of salamander females. Maybe the algae are directly transmitted to the eggs and jelly sacks, as a sort of algal lunch box giving to the embryos by a caring salamander mother. I’m very anxious to see the time lapse video of the algae entering the embryo mentioned in the Nature news article.

Lots of questions remain to be answered of course. How does the salamander immune system recognize the algal symbionts as ‘self’ instead of invader? How are the algae maintained in the adult salamander? And could this short distance relationship develop into a more intimate one – where algal genes end up in the salamander, or where the algae themselves become a new organelle?

For now, this research shows that when close relationships between species turn into dependencies, intimate symbioses are not far away. Such symbioses can eventually blur boundaries between species and drive evolution in new directions. Sometimes, it’s occuring right beneath our noses, in model system that are a hundred years old. On a lighter note, how cool would it be to go to the beach, photosynthesize all day and go back home rejuvenated and refreshed? I’ll pour me an algae cocktail right away!

This research has not been published yet. When the paper hits the databases, I will include the link here.

Despite the obvious benefits of pleasure and procreation, sex has other advantages. The genetic material of both parents gets mixed in [...]]]>

An end to the blogging hiatus at last! I hope to entertain you with the fascinating story on how female wasps got rid of their men and sex in return for bacterial endosymbionts..

Despite the obvious benefits of pleasure and procreation, sex has other advantages. The genetic material of both parents gets mixed in new and unforeseen ways (like a genetic wheel of fortune) whenever a sperm and egg cell fuse. The near ubiquity of sex in the animal world should be enough proof that sex is a good way to increase the genetic variance in the population for these species.

Yet asexual species (parthenogenic species, as biologists call them) pop up every now and then during evolution. One of the most fascinating examples I recently came across is that of the parasitic wasp, Trichogramma, which is often used as biological pest control. While some of these wasp populations exclusively consist of females, this state of asexuality is not some funky route of evolution, it is induced by bacteria!

A Trichogramma wasp parasitizing on the eggs of another insect.

The mood killer in question is a particular species of Wolbachia. These bacteria inhabit the cytoplasm of their host cells. Since sperm cells don’t have any cytoplasm, male wasps are a dead end as far as Wolbachia is concerned. The only way it can be transmitted from generation to generation is via the egg cells (which do have cytoplasm) that develop into female wasps. Normally, unfertilized haploid egg cells develop into male wasps whereas the fertilized egg cells become diploid and develop into female wasps. The Wolbachia messes with mitosis in such a way that every unfertilized egg is diploid, so that only females are born.

In some populations of Trichogramma, the Wolbachia infection rate has reached 100% and males are no longer born. There’s hope for the poor wasp guys though: by treating the wasps with antibiotics, the Wolbachia die out and new male wasps can be born. These male wasps are completely normal: they can inseminate female wasps and their sperm is viable. However, the females from these previously infected populations do not use the sperm to fertilize the eggs. They have become completely dependent on their symbiont for their reproduction.

Without male wasps around to admire her, The Wasp eventually married Ant Man.

This loss of female and retention of male sexual function is fascinating. If all things were equal, both male and female genes necessary for sexual reproduction would erode away at the same rate. Since the males are sexually viable while the females are not, something else must be happening. Stouthamer and colleagues provide an interesting explanation in a recent paper published in BMC Evolutionary Biology. By modelling infection rates, wasp mating and mutation rates they found that a ‘functionaly virginity mutation’ affecting the fertilization rate in females is likely responsible for fixing asexuality in the female population.

The basic gist is that in the initial phase of infection, males will have higher mating rates because there are females aplenty and less males being born. In uninfected females, alleles that reduce fertilization rates (less fertilization, more males!) are being selected for. The uninfected females will produce fewer uninfected daughters and more males that carry the same ‘virginity mutation’. A ratchet is now in place that leads to the fixation of both the infection and the virginity mutation:

Only those females that are not yet homozygous for the mutation will mate and part of their offspring will become homozygous for the mutation. Consequently the class of females that is homozygous for the mutant allele and infected will grow relative to the class of females that is not yet homozygous and infected.

The number of uninfected females capable of normal fertilization dwindles – spelling the end for men and sex. Poor guys. Seriously though, trading in sex for a bacterial endosymbiont.. Where’s the fun in that?

It is the age-old question that has stumped the finest minds for thousands of years. [...]]]>

News sites left and right are picking up a story that “Scientists solved the chicken or egg problem”. Google News aggregated 164 news articles at the time of writing, with more being added every minute. The typical introduction runs like this:

It is the age-old question that has stumped the finest minds for thousands of years. But scientists claim to have finally discovered the answer to the conundrum of what came first – the chicken or the egg?
~Daily Express

Humanity would be in trouble indeed if its ‘finest minds’ are troubled by trivial questions like this! The articles go on to vaguely describe a particular protein that is involved in egg shell formation. While this is certainly interesting, it’s got little to do with chicken evolution or the famous chicken-or-egg ‘problem’. I tracked down the original publication and first online coverage to find out what went wrong here.

The 'who came first' question is trivial at best.

The original paper appeared over a month ago in a chemical journal of the German Chemical Society. It’s a nice study that describes how the carbon carbonate crystals that make up egg shells are formed. The British researched applied molecular modeling to calcium carbonate crystallization in the presence chicken protein ovocleidin-17 (OC-17).

Normally, small amorphous nanoparticles of calcium carbonate molecules don’t crystallize well because the energy barrier for the transition to the more stable crystalline phase is large. However, when OC-17 binds and coordinates the calcium carbonate particles with its arginine residues (described as a ‘clamp’), the energy barrier largely disappears and the calcium carbonate happily crystallizes. When the crystallizing particle starts growing, OC-17 detaches again. The whole mechanism Freeman and colleagues propose really is quite nice.

Ovocleidin-17 coordinates the carbon carbonate particles with its argenine residues, inducing crystallization.

The first online appearance of the story is in this press release of the University of Warwick. I have to admit, the press release really does cover the research pretty well. Of course it ends with some vague promises for crystallization and material science, but otherwise it is a fairly balanced piece. To spice up the article, the press writer decides to include an innocent reference to the famous ‘chicken or egg’ riddle:

The work may also give a partial answer to the age old question “what came first the chicken or the egg?” The answer to the question in this context is “chicken” or – at least a particular chicken protein.
~Warwick University press release

The anonymous writer is careful enough (“partial answer”, “in this context”), but merely being careful is never enough on the internet… The yolk really hits the fan when mainstream news stories pick up on this press release, with metro being one of the main champions of misinterpretation. The following quote from first author Colin Freeman doesn’t help much:

‘It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first,’ said Dr Colin Freeman, from Sheffield University, who worked with counterparts at Warwick University.
~Metro

After the Metro story launched, other mainstream news sites jumped on the bandwagon for a ride. It’s funny and sad to see the whole story turn into a game of Chinese Whispers. ‘Ovocleidin-17′ becomes ‘vocledidin-17′ on Fox News. On various news sites, the study of OC-17 gets reduced to a single sentence. The resulting article doesn’t make sense any more and has become confusing as hell.

Luckily, many readers are smarter than the science ‘journalists’ that have mindlessly copied and pasted this story:

What a silly article. This finding does not “prove” that the chicken came first. After all, if the first chicken did not come from an egg, it was not a chicken. All this really says is that a protein was identified which controls eggshell formation.
… What overblown sensationalist reporting…
~Gabriel on Metro

I didn’t exactly hold mainstream science journalism in high esteem, but I’m amazed that science journalists continue ‘covering’ science stories in this way, even when readers are calling them out. While the trouble may have started with a misleading introduction and a quirky quote, it is the journalist’s responsibility to check facts and put a story into a context. Coverage like this does more harm than good for the public image of science reporting and scientists themselves:

Another brilliant revelation from the British scientific community, but could the tens of millions of pounds of taxpayers’ money that they receive in research grants not be used to discover something of value like the discovery of a new source of cheap, clean energy!
~David, on Metro

Luckily we’ve still got Wikipedia to guide us when we’re misguided and confused:

Wikipedia entry for "Chicken or the Egg"

Oh, wait a minute…

You might not think much of sponges. Maybe you feel that they’re only good for rubbing your back and cleaning your kitchen sink. While you’re absolutely right that sponges have to be admired for their absorbing qualities, they have much more to offer this world. Like on the front of early animal evolution: [...]]]>

You might not think much of sponges. Maybe you feel that they’re only good for rubbing your back and cleaning your kitchen sink. While you’re absolutely right that sponges have to be admired for their absorbing qualities, they have much more to offer this world. Like on the front of early animal evolution: new research by a Croatian team of scientists shows that these simple creatures harbour a genomic complexity that matches our own!

Sponges really are pretty cool animals. As an example, Henry van Peters Wilson discovered the regenerative abilities of sponges in 1907: after putting a living sponge through a sieve, fragmenting its cells in this way, he saw that the remaining clumps of cells found each other again to form what he called ‘plasmodial masses’. After a while, complete sponges emerged again from these ‘masses’!

This remarkable regenerative flexibility might partly reflect the transition that their ancestors underwent from a colonial to a multicellular species (scientists believe sponges evolved from colonies of protozoans much like Monosiga brevicollis). Sponges can lay claim to being the first animals on this planet, and the common ancestor of all animals might very well have been a very sponge-like critter.

Spongia officinalis, or "kitchen sponge". It is dark grey because it is alive, unlike the dried out yellow one in your bathtub. Source.

Sponges are morphologically not very complex. They depend on the flow of water to obtain food and oxygen and remove their waste products. Their porous body structure and skeleton are built to optimize this flow of water, making it flow through all interconnected chambers. Sponges have a number of different cell types, with some that can generate the water flow with their beating flagella, some that can contract and transmit signals like muscle cells and others that maintain and repair the sponge ‘skeleton’.

Such a simple animal must have a pretty simple genome right? Not exactly. Matija Harcet and colleagues sequenced a large set of expressed genes from two different sponges and compared them to their homologs from sea anemone , sea squirt , nematode , fruit fly, sea urchin and human. As you can see in the phylogenetic tree below, the sponges (porifera) occupy a basal position on the tree of metazoans. Consider the surprise when most sponge gene transcripts mapped back to the human and sea anemone proteomes, whereas nematodes and fruit flies ranked the lowest on the list!

Phylogenetic relationships between sponges (porifera) and other animals. We humans are hiding within "Chordata", sea squirts within "Tunicata" and sea urchins in "Echinodermata".

Moreover, the sponge transcripts not only matched the most genes in sea anemones and humans, the protein sequences were also much more similar to human genes than those of other species. You can see this for yourself in the beautiful figure below. Every dot is a transcript that is placed closest to the species it is most similar to. The sponge transcripts most often fall in the human or sea anemone (N. vectensis) quadrants.

A possible explanation for this observation could be that genes have been evolving slowly in both sponges and humans, whereas the proteins of nematodes and drosophila have been evolving in overdrive. Since these species have much shorter generation times and larger population sizes, they can acquire mutations at a much higher rate, speeding up the sequence evolution of their genes.

Each dot is an EST plotted at the appropriate relative sequence distance from the other species.

The team also compared the sponge gene repertoire to that of our closest unicellular nephew: the Monosiga brevicollis that was mentioned before. They found more than a thousand genes which were unique to sponges, of which most are predicted to be involved in signalling pathways and cel adhesion processes. This would mean that most gene expansions and genomic innovations that are found in animals today, were already present in the Urmetazoan ancestor of all animals.

Whatever in happened in that great-great grandmother of animals, it was enough to spawn the whole breadth of animals of the Cambrian explosion and those that live today. Sometimes, simple appearances hold complex and fascinating stories. Not bad, for a ‘simple’ sponge!