Posted: Jun 28, 2020 8:51 pm
Wortfish wrote:campermon wrote:Wortfish wrote:
I would have to say the Mediator complex: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3852498/
Thanks.
But can you describe it?
I can let someone else do it:[Reveal] Spoiler: Someone else's descriptionhttps://www.nature.com/articles/nrm.2017.115In all eukaryotes, mediator of RNA polymerase II transcription (Mediator), a large (protein) complex with modular organization, is generally required for transcription by RNA polymerase II, and it regulates various steps of this process. The main function of Mediator is to transduce signals from the transcription activators bound to enhancer regions to the transcription machinery, which is assembled at promoters as the preinitiation complex (PIC) to control transcription initiation.
Also: https://www.pnas.org/content/106/39/16734Mediator is structurally and functionally conserved across eukaryotes, comprising 25–30 subunits. Structural and biochemical studies have revealed that Mediator exists in an extended conformation, with 3 distinct modules termed the head, middle, and tail; subunits from the individual modules often share genetic properties
I would contend that nearly all of the subunits need to be present for the complex to function at all.
That is an ancient trick.
In Nathan Ausubel’s “Treasury of Jewish Folklore” appears the story of a famous preacher of Dubno whose driver stopped enroute to a lecture date and said, “Rabbi, do me a favor. For once I’d like to be the one receiving all the honors and attention, to see what it feels like. For this one engagement, exchange clothes with me. You be the driver and let me be the rabbi.”
The preacher, a merry and generous soul, laughed and said, “All right — but remember, clothes don’t make the rabbi. If you’re asked to explain some difficult passage of the Law, see that you don’t make a fool of yourself.”
The exchange was effected. Arrived at their destination, the bogus rabbi was received with tumultuous enthusiasm, and obviously loved every minute of it. Finally, however, there came the dreaded moment when an extremely tricky question was put to him.
He met the test nobly. “A fine lot of scholars you are,” he thundered. “Is this the most difficult problem you could ask me? Why, this is so simple even my driver could explain it to you.” Then he called the Preacher of Dubno: “Driver, come here for a moment and clarify the Law for these dull-witted fellows.”
Wortfish wrote:...it takes just one example like this and the whole house of cards could come tumbling down (like a rabbit in the pre-Cambrian).
You have not demonstrated how the mediator complex is analogous to the pre-Cambrian rabbit. To do that you'd have to explain how the necessity of a multiprotein complex breaks evolution. Nothing in the quotes you pasted leads to that conclusion, nor does your attempt to summarise them by writing "I would contend that nearly all of the subunits need to be present for the complex to function at all."