So whose dictation is it taking?
Looking Back 3.8 Billion Years Into the Root of the ‘Tree of Life’
NASA-funded researchers at the Georgia Institute of Technology are tapping information found in the cells of all life on Earth, and using it to trace life’s evolution. They have learned that life is a master stenographer — writing, rewriting and recording its history in elaborate biological structures.
Nw her is an interesting admission:
“The ribosome recorded its history,” said Williams. “It accreted and got bigger and bigger over time. But the older parts were continually frozen after they accreted, just like the rings of a tree. As long as that tree lives, the inner rings will not change. The very core of the ribosome is older than biology, produced by evolutionary processes that we still don’t understand very well.”
So we acknowledge that we still don’t understand them very well?
That’s partly because there is a lot going on in evolution that just wasn’t accepted. It wasn’t accepted because of the insistence that Darwinism (natural selection acting on random mutation generates huge levels of information, and thus is the single greatest idea anyone ever had.
In reality natural selection just means that not all life forms live to breed. That fact was somehow supposed to produce the complex genomic languages and livig machinery we see. And at the same time, prevent Boltzmann’s brain from randomly popping up anywhere.
Never mind, there is plenty of time to catch up. As long as we want to do science.
While the ribosomal core is the same across species, what’s added on top differs. Humans have the largest ribosome, encompassing some 7,000 nucleotides representing dramatic growth from the hundred or so base pairs at the beginning.
“What we’re talking about is going from short oligomers, short pieces of RNA, to the biology we see today,” said Williams. “The increase in size and complexity is mind-boggling.”
“The increase in size and complexity is mind-boggling”? Is sure is, if the stenographer is accepting dictation from no one. More.
See also: Tree of Life: Maybe biological classification is more of an art exhibition than a science purusit
What we know and don’t, about the origin of life
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Here’s the abstract:
We present a molecular-level model for the origin and evolution of the translation system, using a 3D comparative method. In this model, the ribosome evolved by accretion, recursively adding expansion segments, iteratively growing, subsuming, and freezing the rRNA. Functions of expansion segments in the ancestral ribosome are assigned by correspondence with their functions in the extant ribosome. The model explains the evolution of the large ribosomal subunit, the small ribosomal subunit, tRNA, and mRNA. Prokaryotic ribosomes evolved in six phases, sequentially acquiring capabilities for RNA folding, catalysis, subunit association, correlated evolution, decoding, energy-driven translocation, and surface proteinization. Two additional phases exclusive to eukaryotes led to tentacle-like rRNA expansions. In this model, ribosomal proteinization was a driving force for the broad adoption of proteins in other biological processes. The exit tunnel was clearly a central theme of all phases of ribosomal evolution and was continuously extended and rigidified. In the primitive noncoding ribosome, proto-mRNA and the small ribosomal subunit acted as cofactors, positioning the activated ends of tRNAs within the peptidyl transferase center. This association linked the evolution of the large and small ribosomal subunits, proto-mRNA, and tRNA. (paywall) Anton S. Petrov, Burak Gulen, Ashlyn M. Norris, Nicholas A. Kovacs, Chad R. Bernier, Kathryn A. Lanier, George E. Fox, Stephen C. Harvey, Roger M. Wartell, Nicholas V. Hud, and Loren Dean Williams. History of the ribosome and the origin of translation. PNAS, November 30, 2015 DOI: 10.1073/pnas.1509761112 –