Epithelial-mesenchymal transition, adhesive proteins and extracellular matrix

Lately, I’ve been especially active in developmental biology, and gradually I have more and more questions about how multicellular organisms will be implemented in the game. It would probably be most logical to start with the question of how the extracellular matrix could be realized, but the problem is that it is inextricably linked with the epithelial-mesenchymal transition and adhesive proteins (and not only proteins) that, in fact, attach to ECM cells. Also, the cytoskeleton is wedged here, to which adhesive proteins are attached from the inside of the membrane. A question. Will various adhesive molecules be added in the future (e.g. cadherins and catenins), will there be the possibility of customizing the extracellular matrix, and also how will the epithelial-mesenchymal transition and cell migration in the embryo be implemented (in fact, this is the most important part of any animal, without it, they would just be balls of cells). Obviously, this also appears differential gene expression, due to which some cells have certain structures, and some do not, well, here comes the shape of the cell, differential adhesion (as well as the amount of expressed cadherin and cohesion), which plays the most important role in the formation of the embryo and others. By the way, due to the differential expression of genes, the possibility of degradation of organelles within cell types should appear.
Obviously, also, people can write here their ideas about all these mechanisms, and how to implement them (after all, they can?)


Sorry if someone has already touched on developmental biology topics, I haven’t been here for a very long time :point_right::point_left::pleading_face:

Well. That was wordy.

The wikipedia page also had a lot of technical terms. But as far as I understand,

Epithelial-mesenchymal transition (EMT) means that skin cells turn into stem cells and start moving in the extra cellular matrix (ECM). It happens during development, wound healing and cancer (named type 1, type 2 and type 3).

Is it an important type of collective cell migration? I don’t know.

I don’t think player should need to consider how cells migrate inside the organism. When two injuries occur, if there was an option to chose which one to heal first with a type 2 EMT or keep the decision making automated, I would let the game decide, especially if I was running from a predetor that made those wounds.

How could the ECM be implemented? At the beginning of multicellular, empty regions surrounded by cells could be the ECM (like empty hexes in unicellular). But 3d makes things complicated. Do we move all the cells one by one to make a blastula[1]? In late multicellular, tissues can have their own built in ECM’s.

The ECM can be used like a lymphatic system, later evolving into the circulatory system.

Cell adhesive molecules already exist under the name of binding agents. Another binding agent can be added which unlocks cell migration, the same one can do the both jobs, or an upgrade/customisation system can be added which would make the names of existing ones (and non lawk ones?) would become important.

Customisation of the ECM would need to be in the game. Some tissues like hair, feathers or horns are made from keratin which fills inside the cells* while other tissues like bones form by the mineralisation* of collagen, which is an ECM protein. Diatoms have silicate cell walls which is outside the cell, so glass tissues could involve the ECM too.

Another ECM protein is hyaluronan, not to be confused with hhyyrylainen. It exists in tissues like the brain and the skin. A different version of it exists in naked mole rats which makes their skin wrinkly, so that it can stretch and not tear up when the creature is moving underground, rubbing against the soil. But another effecct that has, is that it prevents the cancer cells from migrating, naked mole rats don’t get tumors because of an exaptation. So customisation is nice.

Quoting from khan academy*

The growth of the organisms in multicellular stage could follow their evolution. So if you removed your legs like a snake, legs appear and then dissapear in your development, before or after the birth. This also prevens you from adding a new fully formed* limb to a cow to turn it into a hexapodal dragon. You have to use an existing limb like a bat.

But if a change happens before leaving the womb or the egg, it doesn’t have to be simulated.

There is already cell customisation in the game

modify type

  1. a rather high surface area shape ↩︎

The epithelial-mesenchymal transition is one of the MOST important types of cell migration, thanks to which, if we take vertebrates, a huge number of structures are obtained from neural crest cells located in completely different places. In principle, this, along with the simple movement of cells due to differences in adhesion force, is one of the most important phenomena in development.
The question of the implementation of the extracellular matrix lies precisely in the fact that it forms very, very diverse structures. As an example - basal plate of the epithelium, although it is also bone tissue, blood, etc.
The adhesive molecules we already have are too simple, excuse me. In fact, we must have at least 5 types of such molecules that allow cells with specific types of extracellular matrix to connect with specific cells … It is also important that the number of these adhesive molecules can vary, because this is also one of the most important phenomena in development , I wrote about it - cells with fewer adhesive molecules (and therefore less adhesion) migrate out of cells with more of them, and this migration is VERY important in the formation of germ layers. I understand that most of the embryonic development can not be inserted into the game, but the same germ layers are simply necessary, as is the general plan of the structure.
Unfortunately, the development of an organism does not quite follow its evolution, certain laws work here, called Baer’s laws:
-Embryos of animals of the same type in the early stages of development are similar.

-Embryos of different representatives of the same type gradually separate from each other.

-Embryos successively pass in their development from more general characteristics of the type to more and more particular ones.

-Lastly, signs develop that indicate that the embryo belongs to a particular genus, species, and, finally, individual traits.

And here I touched on the topic of differential gene expression beforehand to explain why the snake example is bad enough. Yes, the snake embryo in its initial stages is similar to the embryos of other tetrapods, and some snakes have rudimentary hind limbs, BUT this does not mean that the snake embryo has legs. Here you can just fall into the trap of not one hundred percent reliability of these laws. The problem is that limb development is determined by the gradients created inside the embryo by transcription factors, limb development is associated with HOX genes. I’d better leave a link to an article that mentions just an example with snakes (ГЕНЕТИКА РАЗВИТИЯ | Баттулин | Вавиловский журнал генетики и селекции). Just because the limbs are not formed at all, we are dealing with the fact that snakes do not even have legs during embryonic development, so Baer’s laws do not quite work in this case (although how to look at it, the absence of limbs is same characteristic of the detachment, and it does not appear immediately)
Here, by the way, the work of differential gene expression is normally described in this way, and why it is not only about different cell types, but also about ALL development of the organism. I understand that most likely we will just make a larva and an adult (even humans go through metamorphosis, I mean, puberty), but still it would be just wonderful to see more functional differential gene expression than we have now (we can’t even turn off the genes of certain organelles, that is, delete them, and it still pisses me off a little that we don’t have the ability to reduce organelles in cell types, although this is the essence of different cell types - in them different genes are expressed :/), because, well, differential expression is responsible for literally everything from cell types to limb development. By the way, it is precisely because of it that the development of a new pair of limbs is possible as a result of a mutation in the genes of transcription factors, due to which the segment with limbs is simply duplicated. By the way, which is quite interesting, many arthropods have fewer limb-bearing segments than vertebrates, as evidenced by the number of nerves that we have per limb (we seem to have five of them each, while arthropods have only one), and we can say that each of our limbs is a combination of several others :slight_smile:
But that’s it, just interesting information

I apologize right away that the article is in my native language, I just remembered for sure that there is just about an example with snakes. I hope you have a translator, if that


So if I understand what you are saying correctly, as it relates to thrive, rather than having specialized cells be placed manually on a grid we would have the player modify the binding agents to decide how parts are placed in relation to each other, for example instead of placing a defensive cells around your body, you would set the cell type to move as far out as possible, creating a shell in the process; correct?

Rather, I proposed a relatively convenient way to set up tissues so that you don’t have to manually set all the tissues, well, that is, by setting up adhesive molecules, you could determine what is inside and what is outside. But here the muscular and skeletal system, probably, will have to be done manually, although here you can think of something. Instead of prescribing types of tissues, such as leather, etc. at the level of the game code, one could simply make the fabric itself and how it is located relative to others, just by the strength of adhesion between cells
Setting up this tissue so that the game itself determines how it is located (well, set cell types and extracellular matrix there)


Doesn’t this only create two types of cells, skin and internal?

How could the players design a colony by changing the amount of adhesive molecules around some cells? If any shape can be created that way, the players might as well place cells wherever they want, not dealing with how that happens. If some shapes can’t be created, the players can still design the final product but with less freedom.

Every limb can have a muscle for it, a slider determining the amount muscle. Even tardigrades have[1] muscles which attach to their skin.(cuticle)


I just tried this, it is possible to remove organelles from different cell types in 0.6.0

Related: there was a suggestion for removing organelles but keeping the gene

I think there should be a two step process for adding organelles, proteins and enzymes. The first is evolving the gene for it (or doing a horisontal gene transfer). This takes most of the dna points. After unlocking it, it takes only a small amount dna points[2] for moving it around the cell or changing the number/amount of it.

What prevents the player from putting 10 mitochondrias? The amount of resources required for growing that cell, and the probability that the cell might die before it can reproduce.

Maybe the dna cost for increasing the enzymes can be made a little bit higher, so that you can’t become an extremophile in one turn. I don’t know how fast they evolved in real life. But copying organelles should be easy, that already happens in mitosis.

yes I have**

coordinates and migration

It is possible* to give the cells only the information in the immediate vicinity of them, and simulate their behavior to get the emergent properties of the organism. Is that how it should be in Thrive?

hox genes

In the multicellular editor, there may be “mini editors”, used for designing internal organs and outside parts like the mouth. The outside parts can be paced on the organism just like how it was in spore, but with a single difference. A point mutation[5] in an hox gene can make your right arm grow from your chest, but would the nerves and blood vessels also be integrated to the rest of the body? They wouldn’t, and this mutation wouldn’t be selected.

So if we put a dna point cost to moving the parts (maybe exponentially more as it is moved farther away), they would only be moved and their sizes changed slightly in each generation[6], forcing the creatures to do wing-assisted incline running before they can fly.

I think growth could still mimic evolutionary history except for some deletions, it could be as if they never happened.

  1. https://askabiologist.asu.edu/tardigrade-anatomy#:~:text=Tardigrades%20have%20muscles%20that%20attach,tardigrade’s%20legs%20and%20body%20around. ↩︎

  2. 5? ↩︎

  3. In reality, the formation of two differently directed gradients at the poles is only the beginning of the deployment of the embryo’s coordinate system. Based on these gradients, new gradients are established that have a different spatial distribution. ↩︎

  4. Programs can be more complex, taking into account the gradients of several substances at once, for example: “if the concentration of substance A in the cell is X, and substances B and C are absent, then activate gene D.” ↩︎

  5. i guess ↩︎

  6. a 10 million year gap between the editor sessions in aware stage? ↩︎

DID THEY ADD THIS?! Okay, then there are no questions.

That’s why I’m talking about the need for a variety of adhesive molecules (so that not all types of cells communicate with each other), although even without it it doesn’t work that way. If we make a slider that is responsible for the strength of adhesion (AM expression level), then even a small discrepancy will cause cell types to line up according to this very strength, so, no

My translator didn’t translate it very well, but I’ll try to answer anyway. In general, as I understand it, you are talking about the fact that specific cells would not be attached to specific points, right? In general, I think that it should also be with organelles - they are not located in real cells at specific points and can move through the cytoplasm (except perhaps organelles attached to the cytoskeleton). Well, yes, I’m talking about the fact that in this way it would be possible to build the same germ layers, from which organs are then obtained, while this would be much more convenient and would give much more freedom to the players than if these sheets were written in code in advance. It can be said that my idea is aimed at making it possible to move away from earthly life, for example, by creating four embryonic foliage, because if they move relative to each other themselves, and not according to the patterns specified in the code, this will bind the players’ hands much less. Also, by setting the same adhesion parameters for two cell types, you can make a mixed tissue, since the cell types will be grouped together. Imagine, for example, a sausage, it has an intestine in the center, there is, for example, a notochord (or a cuticle, or some other exoskeleton), there are segments and muscles, well, that is, of course. With the help of the difference in the strength of adhesion, the muscles will be between the epithelium of the intestine and the integuments, then whether the muscles are attached to the chord or to the integuments can be adjusted (when the muscles interact with the ectoderm, it would turn into ligaments. A similar thing happens between the eye bladder and the ectoderm of the head during the formation of the eye of vertebrates , this is called induction). In fact, in order to create a limb, one would have to do something akin to a notochord (or simply draw out an exoskeleton), after which both muscles and ectoderm will automatically appear that would control this limb. I try to offer something that will simultaneously make the game more convenient, simple and intuitive, but at the same time remove many restrictions. Instead of manually making all the muscles and building a limb, one could simply gradually stretch it, in fact, this is how limbs are built at the embryonic level - first it is baking the ectoderm, then the mesoderm enters there, after which the limb continues to stretch and form it skeleton and muscles

This is a very good suggestion (in fact, this is the only possible option, since in a multicellular organism the genome of each cell is the same as the genome of every other cell, and using transcription factors, you can get every cell type from every cell type (except, I’m not sure about transition from a germline cell to a somatic cell), all the differences are precisely in the methylation of histone lysine tails and other ways of regulating expression, but I do not want to go into this now)


To be fair, there is usually no fixed amount of a particular organelle in cells, rather, there are some limits to it.

I would say that it would be cool to have a larger variety of enzymes that could possibly interact with each other and lead to denaturation of each other, so that life does not seem like honey, and you can’t just take and learn how to digest everything at once. By the way, one could find out why different enzymes are secreted in different glands in order to understand this better (in general, I’m not sure that I translated this paragraph correctly, but I hope I understood everything correctly)


It seems to me that the best way to make a game is to make it simulate life on a fundamental level, the level that everything else comes from. As if many things were done not according to a specific program given to them, but according to a general program according to which everything else works, as far as possible (because I don’t think that at least one computer could pull the ideal life engine that simulates it , and purely on the basis of what happens in it, it would be possible to create any organism). As for me, the best option is to simply make a number of fundamental algorithms and actions for each stage, on the basis of which all the others are built, and then cover all this with convenient controls. Thus, we will get a game with a very high freedom for the player, convenient control. Of course, natural selection will limit the player most of all, which, probably, should be quite tough (after all, otherwise we will get a God simulator like Spore, and not an evolution simulator, albeit directed)

I’m a little unsure about this. In fact, the mutation of the HOX gene does not just move the limb, it moves the entire segment on which it is located (because, one might say, gradients eventually create a segmented body, and if the limb begins to form, the concentration of the morphogen eventually leads to the development of this segment into a complete limb segment). In general, as it is written in the article, evolution to a large extent occurs due to changes in the expression of various genes (in fact, not only HOX, these genes have a fairly large number of families), due to which segments can be duplicated, or elongated (like segments neck of a giraffe, which, despite their small number, has a very long neck), while ordinary mutations can even fade into the background. In general, I’m not sure about this. But about the fact that in order to fly, you must first move the limbs in the right way (did I understand correctly?). Although this is the same as with insects - in order to fly, you must first grow flat processes on your back, then enlarge these same processes, attach muscles to them, etc., in order to eventually learn how to fly.

It doesn’t exactly repeat evolutionary history. It’s just that at first the Embryo shows signs that are characteristic of the entire subtype (secondary or primary mouth), although you can go further and talk about bilateral symmetry, but I don’t think it makes sense. Then signs of the type appear, for example, the presence of a chord. Next, visceral arches (maxillas) are formed, then signs of bony fish appear, sarcopterygium, if we follow the path of birds, we will get signs of reptiles, if along the path of mammals, part of the visceral arches will turn into ears, well, that’s understandable. In short, the joke here is that at first all embryos of the same type are similar, and gradually they will have discrepancies, bigger and bigger. But if an animal, for example, does not have gill arches (hello amniotes), they will develop them and will not

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How could we design anything at all by saying which cell migrates away from which cell? How does that result in them lining up in a line?

Colonies do have a fixed number of cells

For example, each eye of the tardigrade consist of just one cell*. If that cell moved, it would be like our eyes moving in our bodies, I don’t think that happens.

Obviously, we don’t have a fixed number of cells. This change can happen when the player starts to place tissues instead of cells, the number and position of cells no longer being important.

I think changing the position of the organelle should be free in the editor, and maybe their positions can change randomly during the gameplay, especially for the cells that move by making pseudopods.

This was mentioned in another thread

One could say that placing metaballs for individual cells* is the option with the most freedom.

There isn’t even a need to make germ layers, the player can place cells like a 3d snowflake, but the design can be nudged towards the “lawk” design by the enviroment. The need for diffusion prevents a sphere with an inside that is filled, and the fact that other colonies that can trim (eat) the cells that are too “on their own” would discourage regenerating a snowflake shape. If the cells line up in a plane, they all can do diffusion, but the ends of the plane can still be eaten by larger colonies. A sphere (blastula) is like a plane, but it has no ends, the only way to engulf any cells of it is coming with a larger sphere, or breaking it apart.

Also a sphere is aerodynamic (hydrodynamic?), it shouldn’t have anything around it other than limbs to swim with. To increase the number of cells while maintaining a spherical shape on the outside, folds can be created (epithelial-mesenchymal transition of gastrula), which is like a sphere inside a sphere, but everything is connected.

If we end up having the same degree of freedom as we have now, there can still be a tree diagram of cells specialising from each other, but the order of specialisation wouldn’t need to be correlated with where they are located in the colony (like the endoderm and ectoderm of gastrula)

If we decide that spherical colonies and folds are what always happens anyway, we can instead have an editor that is like spore, you have a sphere and you can click and pull it to make folds. I support taking away freedoms in favour of conveniency, but I was told* that people do like freedom.

If I understood your idea, I didn’t like all of it. You said

Imagine we will build a lego house. To draw a blueprint, we would draw how it would look, right? We wouldn’t draw the lego pieces, as they are scattered on the ground right now, and draw their free body diagrams with forces that would throw them to the air the right way so that their trajectories would make them land at the correct positions to make a lego castle.

The extracellular matrix and the molecules that pull the cells, are harder to engage with for the player than the final product. Removing the middle step (cell movement) turns EMT from a process the player directs (by changing the densities) into a physics simulaton where the program does everything automatically to reach the end goal or maybe even into a visual problem that the physics engine occationaly gives a thumbs up. Automation will already happen when the tissue editor is added.

A spore fold editor could be easy to handle by the player

Spesifying patterns in the code (visual problem version) would things simpler. That is not to say it is unscientific, a “proper” simulation can be done beforehand, and the data from that can be used, if it generalises to any type of fold, and why wouldn’t it, because there is just one variable that pulls the cells, and that is the densities.

Yes, but grouping them together doesn’t help if you can’t even move one of them to a spesific place.

That was quite an amusing thing to imagine. :slight_smile: But I get what you mean. There is an animal with a digestion system, which marks the front-back axis.

Cells differentiating based on where they are in the body. Does this make a difference for the multicellular editors?

Would this be true for an alien? What does ectoderm mean anyway?

I think this is a good idea for muscles. For example, for a hinge joint, a flexor and an extensor can be placed at the right locations by the editor.

But, think about octopuses, they neither have bones, nor and exoskeleton, yet they have limbs. And not all bones in our bodies make limbs. I think we should just place a blob that is a limb, it gets muscles, but it gets bones later, or optionally.

I imagined streatching a part in spore creature editor. That would be easier than carrying twenty metaballs.

Interesting. But I though an enzyme had only one substrate, which isn’t something as large as another enzyme.

I don’t know why an enzyme would denature another. Maybe it can change the enviroment (like ph) and make it unsuitable for the other one, but that is an indirect way. But normally, they should be able to work together, and not interact.

Do you mean newton’s laws of motion? As far as possible isn’t as far as simulating atoms, that’s for sure

That’s the hope. The thing is, conveniency may be hard to achieve, but you can always ignore the details, and put a cutscene from the end of tribal stage and start in industrial scene, like spore did. That’s not what I suggest, what I say is that I wasn’t able to imagine how I would change the density in the extra cellular matrix and make the cells move into a blastula shape. Even if I could, I wouldn’t want to do it, especially for every step in the embriogenesis until tissue editor becomes a thing. Taking the evolutionary history is a shortcut, and not entirely unscientific.

oh okay

Exactly. In spore, you would place a wing, and you could suddenly fly, for a short time. And by doing so, you would turn your creature into a hexapod if it was an tetrapod, even though repurposing an existing limb has to take less time and dna ponts that creating a new limb from scratch. Segment duplication doesn’t tend to happen in vertebrates

If we don’t have a momentum for what we are building, if we dont have to stick to our creations and find ways of morphing into new purposes, than stuff like this

wouldnt matter. It is just a leg, being the product of a merger or starting out with the number we have now doesn’t make a difference. But the philosophy of spore, and thrive, is designing everything around you in the game, the past decisions effecting the future. Well, maybe not so much in the case of convergent evolution, but still.

I’m still talking about the later stages of the multicellular stage (this can be understood if you look at what I say, well, about complex embryonic development without a fixed number of cells), so apparently a large part of the answer can be skipped, leaving only this paragraph :skull::skull::skull:

That’s why I’m talking about adding a slider. For the player, it simply means how deep this or that tissue is in relation to others. If we look at the whole organism (of any three-layer animal), we will notice that the ectoderm is always outside the endoderm, and the mesoderm is between them. In essence, the types of adhesive molecules would be configured so that the player determines which tissue connects to which (if anything, we discussed the editor from the very beginning with tissues, and not with individual cells)

Moving tissue to a specific location is, in fact, already organogenesis, which is obviously done by the player manually (in terms of placing organs and modifying them, such as the appearance of a four-chambered heart) while the slider would be used precisely to create something like embryonic leaves (because, well, it’s just convenient when creating the same limb, because, well, when it is formed, in fact, we see that it is the location of the germ layers that decides here, and only then we notice that morphogens (like sonic hedgehog) are connected and more complex structures Initially, the limb is just a bulge of ectoderm and mesoderm, and only then specific structures are formed in it, which could be made a more automatic process, while organogenesis would be partly automatic, and partly not (for example, the heart consists from several tissues, one of which is a modified muscle), that is, after the creation of an organ system (which was originally would be created by the player and does not represent anything, like an empty layer in the graph. Editor), in fact, it is necessary to create organs. Here it would be possible to give the player the opportunity to do everything himself, but also add some presets (cardiovascular system, digestive, respiratory, etc.) so that it was not necessary to manually collect organ systems, but there was such an opportunity if the player wanted it (mad madman madly mad ). But while we are still talking about tissues, while their specialization in specific places with the subsequent transformation into organs can be done simply so that the player takes the resulting organ system, creates an organ and places it. In fact, nothing else is needed, intercellular interactions will do everything for us (the same morphogens, morphogenetic determinants, paracrine factors, all this can be omitted in principle, well, because why overload the player)

No, well, in fact, if we talk about the stages that we are talking about, this is literally the most important thing, which I wrote about a little higher, further differentiation depends on the location, there are interactions of different tissues in different places (an example with the eye bladder and head ectoderm in which due to Pax6 from the ectoderm of the head at the point of contact with the nervous tissue (future retina) the lens begins to form

About the ectoderm, I said conditionally, in fact, it can be an interaction with any tissue

I thought about octopuses. If you look at the previous paragraphs, I wrote about “cuticle and other variants of the exoskeleton”, therefore, I also referred the cuticle to the exoskeleton, so as not to write “cuticle and other variants of the exoskeleton” every time. I’m probably to blame here. In any case, that the muscles of the tongue, that the muscles of the octopus tentacles, are attached (as far as I know) precisely to the outer layer of these structures (if not, correct), so I do not see any problems in creatures without a skeleton. In principle, it is possible to make a limb without bones or a solid exoskeleton.
As for the bones that do not form limbs, if you look at them, it will be either a cranial skeleton (skull) or axial (including ribs). The skull is a rather complex topic worthy of a separate discussion, but the axial skeleton is pretty handy crap. It is segmented, you can just make a number of segments with edges (created manually), a few segments without them, etc., here, again, I don’t see any problems. Plus, the same ribs are interconnected by intercostal muscles. Note that I did not say that all bones should appear in the limbs, I spoke ONLY about how the limb is laid and develops in the process of evolution, without affecting the body itself, therefore I did not say anything about those bones that are not in the limbs , they were nothing to do with

Again, metaballs are an early 3d editor, even before the appearance of the tissue editor, while we are talking about a later editor, when there are already tissues and organs :confused:

Well, all cellular cascades are based on the fact that proteins can denature each other or change each other’s conformation, even if the proteins perform completely unrelated functions, so I just proposed to limit the players from creating such an ultimatum organism with all enzymes at once. Actually, proteins can be stupidly incompatible (although differences in the acidity of the environment can also play a role), because this was not required during evolution, or compatibility does not allow the protein to perform its functions, and there is simply no choice

We are talking about the stage after the advent of the tissue editor (translator, what is wrong with you, what kind of fabric, fabric in the sense of tissue) x3
Here I apologize for this insertion in brackets, it’s just that in Russian tissue and fabric are the same word(ткань)

It was just an interesting fact :slight_smile:

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Damn you and I here shit with letters and words

So it is just about layering. We place metaballs for tissues, we change their adhesive molecule amounts, these balls get on top of each other in layers of concentric sheres, the one with the least adhesive molecules rising to the surface and the one with the most sinking to the center, or maybe the other way round.

After creating the ectoderm, endoderm and maybe a few more layers, we ignore all of this and start modifying the metaballs into organs and stuff.

We were able to say which tissue touches which, because we can determine how much adhesives they have, if similar, than they are next to each other. The only difference “the densest material sinks to the center” makes is that a type of tissue only exists in a single layer, so the skin is always outside and the bone is at the center. But teeth is exposed to the outside, so, yeah. We have multiple poles towards which the sinking happens, so the simple task of making a horn from bone becomes a 5d chess problem.

What is that empty layer? Do the organs have no relation to any other cells placed with the slider method?

Can you, like draw how these happen? And how is cell migration relevant here?

This is the middle ground approach that isn’t that good. If there are presets, wouldn’t a majority of players dodo nothing themselves? Would any of the devs be compelled to add a feature that isn’t used?

Blood vessels would be different than other tissues, they wouldn’t have metaballs. Just like how every limb has muscles, every muscle (and other tissues) would have built in vessels in their metaballs. Upgrading the heart or the respitory organ gives a bonus to all of the body. There is no reason to give anything premade to the player for the digestive system. Just connect an acid secreting tissue of a hollow region.

This sentence can be omitted, why suggest something you see as problematic? I have no idea how a slider makes everything for me and makes the editor simpler.

I am sure this is needed. For example, we have the midasderm, which turns other tissues it touches into gold! Yes, this all makes perfect sense. Even a baby can keep track of all the different transformers.

Instead of the simple simple discussion of choosing an organ (brain) and adding a layer that surrounds it just like how we add cell membranes in cell stage. The unlocked encapsulators are tissues that are previously created, such as a bone, or a combination of bone and muscle in the case of ribcage. Skull is like an exoskeleton.

Filling the region between two metaballs with a cylindrical[1] isosurface is, I assume, a thing that can give us the effect of streching.

  1. the raidus is equal to the radius of the spheres ↩︎


I’d have to do more research to make sure I fully understand everything discussed since I’m sure some things have went over my head, but from my understanding, this discussion is addressing a level of detail that is likely too much complexity to put into Thrive.

We will be implicitly representing certain biological phenomena. For example, I want to make sure late-multicellular progression is designed in a way that is aware of the difference in morphological capabilities between animals who are diploblastic and triploblastic. An early concept on the developer forums I had made these germ layers a huge part of the game, but we decided that would be hard to explain/deal with and thought we could just implicitly simulate them. And by the way, by implicitly simulate, I mean not make a dedicated mechanic for it but organize things so that it emerges naturally.

We also will be taking a look at adhesion proteins later to make sure there’s a bit more to progressing to the multicellular stage than “put this part down and collect 5 other dudes”. Though I haven’t really thought about that much at all yet, I’m sure I’ll look at this thread/information for inspiration regarding that discussion.


I said three times that there are no more metaballs, we are talking about a late multi-cell editor in which we work with tissues and organs. There is a slider, if you move it back - the tissue is deeper, if you move it forward - more outside, that’s it, I did not affect individual cells or metabolites

Two questions. 1. Why put an owl on a globe and try to make a horn out of bone? 2. If we’re going to do that, why can’t we use the subcutaneous ossifications like in the skull? We simply ossify the connective tissue in the skin and get the bone (approximately, I do not speak in detail, because I am too lazy and I want to sleep). If we take osteoderms, we only need to stretch out the ectoderm with the formation of bone in the elongated part, and then perhaps change the integument of this horn so that it is covered with a substance such as keratin or chitin. I still don’t see a 5d chess problem here

An easy way to move from one organ system to another. An empty layer is an organ system in which there are no organs yet to appear. This is not about interaction with other cells, but about ease of use (if it is not possible to look at one or more organ systems separately, it will be very difficult for players to change them in any way)

I’ll do it today / in the morning Moscow time

You see, there is a very unpleasant situation here, called the circulatory system. If I can imagine how to implement nerves (because the nervous system is segmented) or an open circulatory system, then I don’t know how to implement all the blood vessels. It might be possible to add some kind of button that allows you to generate the ducts of the system, but, again, this would require separating the circulatory system (which should carry oxygen and nutrients throughout the body) and other systems. What I’m talking about. If we generate ducts (vessels) for the circulatory system, they will work in such a way as to carry oxygen and all substances throughout the body, everything is fine here. But, if you take the human systems, there is also the lymphatic system, which simply enters the bloodstream in the superior vena cava. I don’t have questions like how to realize breathing or nutrition, if there are vessels, there’s nothing to do here - bring the vessels to the lungs or gills, the blood sucks in oxygen or nutrients and simply flows further through the vessels. I only see problems in, I don’t know, hierarchies of organ systems? I already forgot what the question was about, I want to sleep, so now I will try to be more concise

And here the slider in general, if I’m talking about organogenesis, while the slider only determines which tissues are deeper (and, therefore, determines where the organ, muscle or something else will be located (for example, muscles will always be under the skin, and the gastrointestinal tract will always be the innermost part of the body (I hope you understand what I mean))). Paracrine factors, morphogens, etc. are about the formation of specific structures, from eyes and organs to limbs and head. So the player simply makes the structure of the same eye and can move it around the body of the animal. The same is true for the brain and other organs.

So the point is that intercellular interaction, like morphogens and everything else, can be omitted, because in the end the player will just have to arrange the organs in the body, after which everything will work out by itself. Therefore, no one needs to keep track of all this, it works to some extent like the Spore editor (although this comparison is probably not the best). No need to think about what morphogens or paracrine factors do what, you just need to make an organ from some tissues (even from different germ layers, like the same eye), set its shape (if this is even possible, it would be just magical, if its function followed from its structure, and was not set manually by the player) and place, that’s it. We don’t even need to do paracrine factors, morphogens and everything else in the game, we have a ready-made creature, and its embryonic development essentially works according to Baer’s laws (I wrote them above). The slider has nothing to do with the organs, it is needed to build the basic structure of the body so that the muscles cannot be outside the skin, etc.

I seem to understand what you mean. But here the situation is such that it only works with the brain skull and replacement bones, but there are also integumentary ones. Plus, it is important to understand that this does not apply to the visceral skull. Although everything is really clear with him - we create gill arches, from them visceral ones, we get cartilaginous jaws, we already have a simple cartilaginous skull, now it should ossify. Also, we supplement it with osteoderms, which become integumentary bones. Well, that’s it, the skull is ready👍🏿
The chest, again, is painfully simple, we take a segment and form a rib in it, then we choose the size of the segment. Also, we can make a sternum that is not related to specific segments (just make it not in something like the segment editor, but in the editor of the whole animal, for example), the ribcage is ready. Through the sternum and clavicles, we connect the limbs to the chest (just for example) well, like, I still don’t see the problem (not again, but again (untranslatable Russian expression))

And as for the teeth, in fact, the vestibule of the oral cavity is the ectoderm, the teeth appear just in it, so, well, everything is fine. Given that a person is a kind of elongated “doughnut”, it is quite logical that there will be junctions between the ectoderm and endoderm (in fact, this is the entrance and exit of the gastrointestinal tract, well, and other ways into the internal cavity of the body)

Type all the end of the discussion? Nobody else wants to discuss something related to the topic? :pleading_face::pleading_face::pleading_face: