Nicole King (UC Berkeley, HHMI) 1: The origin of animal multicellularity

www.ibiology.org/ibioseminars/...
Talk Overview:
Animals, plants, green algae, fungi and slime molds are all forms of multicellular life, yet each evolved multicellularity independently. How did animals evolve from their single-celled ancestors? King addresses this question using a group of fascinating organisms called choanoflagellates. Choanoflagellates are the closest living relatives to animals; they are single-cell, flagellated, bacteria eating organisms found between fungi and animals on the phylogenetic tree of life. By sequencing the genomes of many choanoflagellate species, King and her colleagues have discovered that some genes required for multicellularity in animals, such as adhesion, signaling, and extracellular matrix genes, are found in choanoflagellates. This suggests that these genes may have evolved before the transition to multicellularity in animals.
The choanoflagellate S. rosetta can exist as a unicellular organism or it can switch to form multicellular colonies. In fact, its life cycle can be quite complex; it can form long chain colonies, spherical colonies called rosettes, or exist in different unicellular forms.
In part 2 of her talk, King explains how she chose to use S. rosetta as a simple model for animal origins. After overcoming the technical difficulty of getting S. rosetta to form rosettes in the lab, she investigated how rosettes develop and how the cells within a rosette adhere to each other. She also asked the intriguing question “What regulates rosette development?”. It turns out that rosette formation is regulated by lipids produced by environmental bacteria that S. rosetta eat. This result adds to the growing interest in how bacteria may be influencing the behavior of diverse animals including humans.
Speaker Biography:
While fossils sparked Nicole King’s childhood interest in evolution, she realized that the fossil record doesn’t explain fully how animals first evolved from their single celled ancestors. To answer this question, King decided to study modern day choanoflagellates. Choanoflagellates are single celled organisms that can also develop in to multicellular assemblages.
King first learned about choanoflagellates while she was a graduate student with Richard Losick at Harvard University. She moved to the University of Wisconsin-Madison to do a post-doctoral fellowship focusing on choanoflagellates. In 2003, King joined the faculty at the University of California, Berkeley. Currently, she is a Professor of Molecular and Cell Biology at Berkeley and a Howard Hughes Medical Institute Investigator.
King’s innovative studies have been recognized with a MacArthur Foundation Fellowship and a Pew Scholarship. King is also a Senior Fellow of the Canadian Institute for Advanced Research.

[@mdhbigdog]

Nicole King's work with choanoflageles was discussed in Neil Shubin's book, "Your Inner Fish."

[@paulthew2]

Fascinating. Many thanks. I will now find out more about choanoflagellates. It's been seven years.

[@100ironclaw]

+iBIology and Nicole King, thanks a hundred times over for the talk. I had always found this particular topic matter both perplexing and intriguing so after hearing your lecture I found myself with even more questions and all the more curiosity! Keep up with the good work and I hope you will do another follow-up to your research here at iBiology.

[@citizenschallengeYT]

Excellent speaker, amazing content. Thank you Professor King

[@judyprice9434]

Thank you. particularly, for shedding light on the nature of LUCA.

[@StewartChaimson]

Thank you for making and sharing this interesting and informative lecture!

[@bryanhamilton120]

She's my professor! I hope her final isn't too bad!!

[@claireclarke6156]

how was the exam?

[@Booklamp53]

Great lecture :) Very exciting!

[@penaryproductions2275]

Thanks for the video! It was thorough and enjoyable, and helped me better understand what I am learning in biology.

[@iAmEhead]

Been reading The Deep History of Ourselves and this lecture was perfect for filling out some of the details. Thanks!

[@lydiadelrio]

Thank you for this great and enlighing presentation.

[@doodelay]

excellent talk! so interesting and onto part 2

[@Petrov3434]

Outstanding presentation !!

[@GeoffryGifari]

If multicellularity evolved independently for plants, fungi, and metazoa, does that mean this choanoflagellate research to discover the origin of animal multicellularity has analogs for the origin of multicellular plants and fungi?

[@MrRobertX70]

This was so interesting! I wish I continued studying biochemistry

[@alexgil4623]

Gracias, buen trabajo...

[@StewartChaimson]

Fascinating, thank you very much.

[@listen2164]

most animals have at least a blastula stage, and most, but not all, have a gastrula stage. i love this video, and just wanted to share that.

[@elder.batista]

I would like to translate the subtitles of this very nice talk in order to use in my zoology classes. Could you guys make it available for community contribution?

[@robotaholic]

This is great, thank you

[@GeoffryGifari]

If we have a gene that governs, let's say, cell adhesion in choanoflagellates and there's also a uniquely animal cell adhesion gene, will we see similarities in the base pairs of the two genes, knowing that choanoflagellates are closely related to animals?

[@zada2423]

thank you ...

[@GeoffryGifari]

Does this research mean collar cell is one of the most ancient animal cell type?

[@ryattel1]

Спасибо!

[@bryan3dguitar]

Too difficult to synchronize the audio and video?

[@robertlipka9541]

Has anyone researched the possible paths to multicellularity in plants and fungi?

[@TheBartgry]

Plants, fungi and animals all evolved multicellularity independently. Evolution of cellulose and chitin cell walls was a crucial aspect. All of them still have some signaling pathways in common, that were present in their common ancestor: like cyclic AMP, calcium, Rho GTPases.

[@matthewrevell2706]

Does this mean that multi-cellular life is common in the Cosmos as so many paths to multi-celluraity are found on just Earth?

[@LuisAldamiz]

What you say makes sense. However, for what we know, it took a very very long time for multicellular life to coalesce, while unicelullar life was instead present since soon after Earth cooled enough. So, if we are to learn from this only example we know of, the provisional conclusion should be that complexity (hence multicellularity) does arise but it needs time. Why? My guess is that there's a long story of unicellular evolution until some branches of it are ready to make the jump and also let's not forget that evolution has internal complex dynamics, so maybe there are factors (either pressures or potential untapped niches) that, since some compexity threshold, drive multicellular adaptation. One key factor is comensalism and symbiosis for sure, only symbiotic cells can jump to true multicellularity.

[@RonJohn63]

No, because most of the stars in the Universe are in *really hostile* places (most near the center of that galaxy and thus bathed in ionizing radiation, or the whole galaxy in like that) and most planets around those stars are hostile. Even most planets are hostile to life: too hot, too cold, bathed in sterilizing radiation, etc, etc.

[@corneliusprentjie-maker6715]

but isn't it all actualluy electro-magnatisim... the dance of charged debris... near photon sources that make interplay possible of the... various particle sises...

[@TheBartgry]

@@RonJohn63 there are millions of planets known that orbit in the 'habitable zone' of their star. Earth-like planets are remarkably abundant.

[@RonJohn63]

@@TheBartgry"rocky planet in the 'habitable zone' is an absurdly broad definition of "Earth-like", which lacks a *lot* of the requirements for life.

[@girish869]

what is the exact point that a unicellular organism converted in to multi cellular one, what makes them so exactly over generation to generation. are they any cases about multi cellular to uni cellular conversion.

[@matthewrevell2706]

Watch the full video.

[@TheMeshHeads]

cobb sent me here.

[@agitapelotudos]

pongan subs en español por favor :O

[@jomen112]

To one of the big questions I already have the answer. The Evolutionary implication of multicellularity is pork shops and hamburgers. Now where can I get a research fund to study these things?

[@cerberaodollam]

Why only the animals have a pretty rigid body plan? I mean a tree can grow as many branches as it pleases and a fungus can sprout mushrooms anywhere on its body, but you gonna have 4 limbs and 5 fingers and your nose will be in a specific place no matter what. And I'm like why?

[@Littleprinceleon]

To my knowledge trees also grow branches according to a general plan (less precisely defined rules, but based on geometry, too): it just happens to be more flexible, because in the worst case, a particular branch will not have enough light and/or space to expand fully... also trees also need to balance themselves, slowly but surely, so no, they can't just grow branches wherever it "pleases" them. I would be curious how fit you would have been in the prehistoric times with an arm growing out from the middle of your back - 😅 In most situations a non-paired limb for terrestrial animals would be a huge OBSTACLE (especially when running or quickly climbing or swinging from one branch to the other). It would also be an unnecessary COMPLICATION eg. due to the need for extra genetic planning: specifically the proper innervation, nourishment and active regulation of its use: the effort needed to learn how to use it effectively, etc ... Just read some stories of people who (due to neurological reasons) had to COMPLETELY re-learn how to walk again: it requires an ENORMOUS effort. (I have an intuition for this from practicing Tai chi which also necessitates a substantial "re-wiring"). A symmetric body extension is more reasonable: however, if an additional pair of limbs (requiring bigger and more complicated body: eg. more vertebrae for extra flexibility ) would result in a favourable cost/benefit ratio, then we would see terrestrial animals with six limbs. As for the fish: there's a great variety in the number, size and placement of FINs...

[@lucaspierce3328]

Fossils might not tell the whole story, but genes and DNA surely don't either. What needs to be included in the topic of the origins of multicellularity is epigenetics, plasticity, morphodynamics, multi-level selection and other marginalized and valid mechanisms and Dynamics. They always go back to bottom-up processes and never to top-down processes in developmental evolution. In reality those two approaches are connected and to choose just one is ideological and wishful thinking. A more developmental systems perspective is needed. Refinements in our models as well as fusions of others into a more integrative synthesis. A gene or genomes, are co-dependent on other genes and genomes, as well as their internal-to-external environmental relationships. Indeed a more gene-organism-environment point of view is necessary for a more accurate understanding, which I call eco-evolutionary developmental dynamics..!

[@celestial6489]

How are biologist going to study the epigenetics for species long extinct? Can't really dictate the impediments to growth, birth, etc., outside predictions from the DNA microsatalites and other remenants left on living species or preserved DNA samples. I do agree that a lot of these modern genes were more than likely just a form of plasticity, and the speaker even mentions that they hope to uncover their original function. The speaker probably didn't want to bog down her speech with info educated listeners should already know.

[@Littleprinceleon]

While I appreciate your enthusiasm, scientific research just like any complex social activity has to build upon "traditional" approaches. You can't just develop methods out of thin air based on lovely ideals. Especially if you have to be productive from early on, but why would anyone gave you finances if you haven't proved your worth? You have to become a somewhat successful member of an existing group, so the transformation of research (just like evolution) takes time. Of course there are also outdated inertias (tendencies): even scientists are humans at the end of the day. There are still active biologists who started their career when PCR wasn't even dreamed of. Two decades ago even multidisciplinary approach in areas of biology was a rarity, now it slowly becomes a necessity. Those youngsters starting now won't even feel satisfied if "narrowed" too much, given how quickly they can gain (even if sketchy) views on any topic from different perspectives. When I studied at university (from 1998 in Slovakia) even internet and computers were such cumbersome, that I couldn't even imagine how powerful bioinformatics can be. Top-down inquiries are only fruitful if you have a solid grasp of the involved systems: How do you achieve sufficient understanding of understudied organisms without bottom up style of studies? Of course, once you have good models and enough data, you can start to generalize...

[@RonJohn63]

Was she pregnant? (Just curious.)

[@andrestenzel9055]

Well spoken, however Nicole King is an animal as am I, as an animal I seek warmth an food. The display you convey is specialization (predator/prey). As any good predator as prey is less abundant should I not develop a more diverse my pallet? Articulating thumb(came before brain, accident or divine intervention?) Harness fire (would an animal not be more palatable if burn in a fire) (cooked)? I submit a predator (animal with an articulating thumb learned to create fire to cook), now has the ability to look back and ponder.

[@gb1konobi]

so this is going to help me in what way?

[@corneliusprentjie-maker6715]

Perhaps knowing thzt our bacteria are commensal... will prevent us from over steril-lie-zing our own environments. So the bacteria can help switch your lights on and off. i wonder pour example if they help activate genes... that release hormones... that influence your mood, microbiology and perception... immune reaction... i mean they do digest your food. Any constructive insights? I think a less sterile environment helped our ex-autistic child be less ...sick. Bacteria (exposure there to) helped him be sick less often. I think. So i hope... you are right probably to you... it is nothing. But i looooove it!

[@patldennis]

make you smarter

[@JungleJargon]

You are assembling the organism backwards. Cell division and specialization is top down, not bottom up.

[@patldennis]

She talks about predation.

[@JungleJargon]

@@patldennis Predation eliminates.

[@patldennis]

@@JungleJargonwhat does it leave in the context of natural selection?

[@JungleJargon]

@@patldennis It eliminates the selection.

[@patldennis]

@@JungleJargon Wrong. The colony forming choanoflagellates are better at gathering nutrients thus the mutations that facilitate colony firming are selected and become fixed in the population. The environment having such a pipeline into the gene pool of the population surely must fit your concept of "top down".

[@BR-hi6yt]

Sorry but I wasted 27 minutes listening to obscure biological details and "work that needs to be done". I expected to hear about how single cells learnt to communicate with each other via bioelectricity or whatever. You need a very very smart biologist to be able to speak about this. Someone like Levin for example.

[@slightlygruff]

congrats on trying to have a kid

[@jayh9529]

Darwin was a free mason

[@corneliusprentjie-maker6715]

i knewer new. Is it true?

[@mynamemylastname7179]

So a Red Dot connecting the lines proves that all animals share a common ancesstor. wow brilliant scientist. Lol

[@patldennis]

Just as much as your yearly budget in pie chart format proves your economy is based on pie.. ever heard of a graphical representation of data, dimwit?

[@TheBartgry]

@@patldennis Hahaha golden response

[@patldennis]

@@TheBartgry just noticed this.. lines connect dots; not vice versa. Creationists have perpetual foot in mouth disease.

[@TheBartgry]

@@patldennis well maybe. But please don't polarize the discussion. Just ignore comments like this. Enjoy the science. Its better for your mental health trust me👾

[@patldennis]

@@TheBartgry I believe that people who are investigating new topics can benefit from comments left in the virtual realm that call creationists out on their bs. If I die tomorrow such comments will be my small but long lasting contribution to science advocacy.

[@JungleJargon]

Nothing can ever be what it has no written directives to be. Unrelated changes to existing information will never program information that's not there.

[@patldennis]

Your name is so appropriate to such nonsensical ramblings

[@JungleJargon]

@@patldennis What did I say that is nonsensical?

[@patldennis]

Your previous comment reads like a randomly generated Deepack Chopra quote

[@JungleJargon]

@@patldennis You aren't telling me anything.

[@patldennis]

@@JungleJargon you won't ever understand me bc I don't speak gibberish

[@Zarkzark]

Assumptions, if the scientists talk about our past and try to explain things, it is always overloaded with assumptions, always. Boring.

[@laserfan17]

Pond64 Of course you have to make assumptions when talking about the distant past you dimwit! The difference between these smart scientists and you is that they actually use their brain to try and decipher events and phenomena that we can’t directly observe, all based on evidence and decades of studies and research, to deliver comprehensive explanations about life itself, they may not know everything but you don’t know anything.

[@patldennis]

Creationists and science deniers don't understand that an assumption in the context of hypothesis, deduction, induction, testing and subsequent observations are elevated above the rank of assumption. Just like they don't understand the difference btwm a scientific theory and armchair speculation

[@schmetterling4477]

What assumptions did she make? Please elaborate. :-)