I'm a math biology (in other words, I use math to model biology problems) student, and not an evolution nay-sayer, and...the scientific work isn't at all about showing how the amazingly (I'm a student, I learn to respect my opponent) complex phenomena underlying the emergence of organs can be neatly associated with single events.
In particular, this article was of interest to me simply because of how grand a claim it makes.
In general, grand claims are something to approach with skepticism, because of laws of probability number 35, which states that: "few complex non-linear phenomena have a beautifully simple explanation, and if a grand claim purports to be such an explanation, then it most likely is not such an explanation".
It is worth reading law 36 of probability as well: "the maker of a grand claim is more likely to be a 'journalist' or a PR department person, than a scientist".
How do the laws of probability hold up? Pretty darn well, I'd say.
Here's the abstract (by the way, eLife IS an open source journal, so the journalist had no excuse here):
> To form and maintain organized tissues, multicellular organisms orient their mitotic spindles relative to neighboring cells. A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues. Here we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism. The complex was assembled through a series of molecular exploitation events, one of which – the evolution of GKPID’s capacity to bind the cortical marker protein – can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID. This change revealed and repurposed an ancient molecular surface that previously had a radically different function. We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals.
Key takeaways:
1) "A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues"
Explanation: in this sentence, the scientists are carefully pointing out where the 'thing' (a protein domain) they are going to make a claim about fits into the biological picture. No, there isn't one superhero -- there's a carefully choreographed concert that their 'thing' is a part of.
2) "we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism"
Very cool. Simple statement. Interesting, but no grand claim.
3) "The complex was assembled through a series of molecular exploitation events, one of which – the evolution of GKPID’s capacity to bind the cortical marker protein – can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID."
Again, they reiterate how there was actually a bunch of things happening ("a series of molecular exploitation events"), ONE of which is the cool one they want to talk about.
4) "This change revealed and repurposed an ancient molecular surface that previously had a radically different function."
If you were wondering what's cool, this is what's cool.
5) In conclusion: "We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals."
Hmm...no grand claim finishing claim made regarding how this ONE thing changed EVERYTHING. Again, we are reminded of the whole picture: "so yeah guys, here's how this protein function, which is essential (because it's part of a super complex dance number) for so many living things, probably came about".
I'm going to go commission a gold filigree copy of the laws of probability.
Thanks for looking into the original document and providing a detailed explanation. You are basically saying that the journalists sensationalized the findings. The researchers do not claim that they traced the most ancient mutation responsible for multicellularity. The researchers also do not claim that this single mutation created an almost functional multicellular organism.
Am I getting this right?
Mind you, the scientists still can't entirely stop themselves from making somewhat grandiose claims:
“That’s a very different paradigm for thinking about diseases like cancer,” Prehoda said. “It could allow us to think about new ways to develop therapies by focusing on genes that are involved in this unicellular to multi-cellular process.”
In particular, this article was of interest to me simply because of how grand a claim it makes.
In general, grand claims are something to approach with skepticism, because of laws of probability number 35, which states that: "few complex non-linear phenomena have a beautifully simple explanation, and if a grand claim purports to be such an explanation, then it most likely is not such an explanation".
It is worth reading law 36 of probability as well: "the maker of a grand claim is more likely to be a 'journalist' or a PR department person, than a scientist".
How do the laws of probability hold up? Pretty darn well, I'd say.
Here's the abstract (by the way, eLife IS an open source journal, so the journalist had no excuse here):
> To form and maintain organized tissues, multicellular organisms orient their mitotic spindles relative to neighboring cells. A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues. Here we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism. The complex was assembled through a series of molecular exploitation events, one of which – the evolution of GKPID’s capacity to bind the cortical marker protein – can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID. This change revealed and repurposed an ancient molecular surface that previously had a radically different function. We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals.
Key takeaways:
1) "A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues"
Explanation: in this sentence, the scientists are carefully pointing out where the 'thing' (a protein domain) they are going to make a claim about fits into the biological picture. No, there isn't one superhero -- there's a carefully choreographed concert that their 'thing' is a part of.
2) "we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism"
Very cool. Simple statement. Interesting, but no grand claim.
3) "The complex was assembled through a series of molecular exploitation events, one of which – the evolution of GKPID’s capacity to bind the cortical marker protein – can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID."
Again, they reiterate how there was actually a bunch of things happening ("a series of molecular exploitation events"), ONE of which is the cool one they want to talk about.
4) "This change revealed and repurposed an ancient molecular surface that previously had a radically different function."
If you were wondering what's cool, this is what's cool.
5) In conclusion: "We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals."
Hmm...no grand claim finishing claim made regarding how this ONE thing changed EVERYTHING. Again, we are reminded of the whole picture: "so yeah guys, here's how this protein function, which is essential (because it's part of a super complex dance number) for so many living things, probably came about".
I'm going to go commission a gold filigree copy of the laws of probability.