Roots Of Earth's Tree Of Life

[Dov Henis]

(posted also in another biology forum 26-28 Nov 2006)

 

AG wrote:

 

How is the Tree of Life rooted?... What could the last universal common ancestor be?

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Dov:

 

See title #194 in my blog, Study of Life's Base:

http://blog.360.yahoo.com/blog-P81pQcU1dLBbHgtjQjxG_Q--?cq=1

 

(A)

 

Scientism and "evolutionary thinking" suggest that the study of the nature of life must be focused on the nature of the presently known earliest genes and on the probable nature of their probable earlier editions, backwards to the treshold of formation-transition of pre-RNA chemicals into their self-replicating RNA editions, in the company of their precursors and of the predecessors of the precursors.

 

(:lol:

 

Most probable conjecture of the constellation of the Stealthy Life Genesis:

 

(1) In a (need composition definition) aqueous medium are present all components of the early "replicating configurations" plus all the predecessors of those components, and (2) the energy balance of each of the progressing (steps) reactions, along the direction from the base elements level up to the replicator, are always forward-favoured, so that in the presence of all the required elements the replicator's formation energetically draws the progressive reactions.

The starting clues are, of course, the earliest available mono-cellular compositions and their in-cell processes, and the starting unknown variables are the systems' base molecules and the systems' energetic circumstances.

 

©

 

The essential early events of the energy-contents-driven "chemicals-to-life" progression comprise single-strand base extensions and ligations. Later steps include DNA formation.

All the consecutive steps in the progression are energy-contents-driven. Thus the chemicals-to-life transit is not a single dramatic step/rung of the ladder but consists of multi-small-steps/rungs and, due to variations in circumstances and in-line with the fractal nature of everything in the environments, it is random/stochastic.

 

(D)

 

I conjecture life's genesis much earlier than celling of genes. I suggest that genomes are communal coops of what way back originally were RNA independent genes, these various/different genes being then the first proliferrable life forms. Evolution and survival directed them and their DNA progeny to become united, chromosomes and genomes, simply because cooperation is the most survivable mode, and the further process of evolution included celling for control of environmental parameters plus ever increasing member genes specialization as more capabilities evolve by some individual members of the commune of genes.

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AG :

 

I was also leaning toward Woese's theory which can be read here:

 

http://www.pnas.org/cgi/content/full/95/12/6854?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=universal+ancestor&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT#B14

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Dov :

 

Genesis And Life

 

Carl Woese ( June 9, 1998 ):

 

"The ancestor ( of life ) cannot have been a particular organism, a single organismal lineage. It was communal (13, 22), a loosely knit, diverse conglomeration of primitive cells that evolved as a unit, and it eventually developed to a stage where it broke into several distinct communities, which in their turn become the three primary lines of descent".

 

Dov Henis:

 

Earth life's genesis cannot have been cell(s). Cells, like all (every) objects and processes and natural laws in the universe, are - since singularity - products of evolution and are continuously further evolving. Everything in the cosmos is fractal, rehappens on many scales, and is continuously evolving. Each and every system in the universe continuously evolves within the total universal evolution and all the systems' evolutions are intertwined. Thus the root of earth's life cannot have been deus-ex-machina cells. Cells cannot have been but one of the forms of products of evolution of energy-transformation-storage systems, since at the beginning was the energy singularity, at the end will be near zero mass and an infinite dispersion of the beginning energy, and in-between, the universe undergoes continuous evolution consisting of myriad energy-to-energy and energy-to-mass-to-energy transformations. Therefore the roots of earth-life's genesis must have been much earlier than the celling of genes, in cosmic phenomena of active temporary reservoirs or pockets or bubbles of energy, on Earth in formation of individual RNA replicating genes.

 

Dov

[InfiniteNow]

So, what's your question? Do you have a point of discussion, or are you just shouting, "Hey everyone, look at this!"?

[HydrogenBond]

The earliest lifeforms probabllywere based on RNA genetics. The reason this is so is because RNA forms a single helix, instead of a stable double helix, making it easier to transcribe with rudimentary proteins. Virus may have been around very early. Incomplete duplication of the RNA would produce fragments that could bind to proteins.

 

DNA differs chemically from RNA, in simple terms, because it is more reduced. It has more reduce hydrogen per monomer unit. This would require a more advanced mechanism for molecular synthesis.

[Dov Henis]

So, what's your question?

 

Have answers will scribble...?!

[HydrogenBond]

One of the things that is rarely discussed in early life is ion pumping at the cell membrane. Modern cells pump sodium ions and exchange potassium ions. This net result is a membrane potential where the inside of the membrane becomes slightly negative. What is significant about this is that the negative charge inside the cellular membrane is loosely analogous to a slight reduction potential being created in the cell water. This could have helped drive the transition from RNA to DNA. In other words, it will make that reduction reaction occur a little easier.

 

In my opinion ion pumping was the key to the quickening in cell evolution. It is not cooincidental that when cells enter the cell cycle, the membrane potential lowers and the inside becomes less negative. Instead of a slight reduction potential, things insde of the cell shifts more toward a slight oxidation potential. The metabolic oxidation potential increases to help drive all the synthesis. After the DNA is duplicated, and the daughter cell separate, their membrane potential is restored, i.e, reduction potential, and the DNA goes about its normal business. The importance of the ion pumping seems self evident.

[HydrogenBond]

This morning, another idea came to me. When the DNA is duplicated, during cell cycles, the final step is an enzyme that checks for errors and makes the needed changes to assure proper based pairing. This is sort of a spell-check enzyme that makes sure all the genes are translated correctly on the new DNA.

 

In one considers the earliest cells, the spell checker was probablly not that great, i.e, version 1.0. It not only would miss errors, but may even make errors of its own. The result should have been continuous mutations. If we assume the initial duplication of the DNA is 99.9% perfect and spell check was 50% accurate, that is a lot of mutant genes appearing every cellular generation.

 

The spell check theory provides a possible reason why dinosaurs were so large. Picture if the muscle tissue had poor spell check, instead of being composed of say a half dozen muscles cells, it could be more like hundreds that are very similar but slightly different. This would make chemical feedback control of the muscles more difficult. The result could be far more complex tissues that keep growing and changing, in situ. As spell check became more effecient, the variety of cells decreased allowing smaller animals with tighter control of cell replication.

 

Everyone is welcome to pursue the spell-check theory for mutations in earliest life. A solid scientific paper will add something new to existing evolutionary theory.

[Buffy]

The spell check theory provides a possible reason why dinosaurs were so large. Picture if the muscle tissue had poor spell check, instead of being composed of say a half dozen muscles cells, it could be more like hundreds that are very similar but slightly different. This would make chemical feedback control of the muscles more difficult.

Actually, cell replication is a minor change to DNA: Our human brains are almost identical to lower primates *except* for the number of cells.

 

As mentioned in some other threads though, the amount of scaling that happened to produce dinosaurs was much more than simply growing more cells, and indeed a set of changes have to occur involving changing whole structures in order to support the additional size.

 

What this concept of "more error prone spell checking" may do though is provide some explanation for why the much more rapid and dramatic morphological changes that created the major kingdoms and phylla of life happened early in the history of life, but has "slowed down" over the millenia.

 

I don't know of any research that talks about this concept, but I am not an expert in archaeobiology! It sure sounds interesting though!

 

Taxonomically,

Buffy

[HydrogenBond]

Lets take the spell check analogy a little further. If one was proofing a paper and providing spell check, if the word is ambiguous, depending on the choice of word, one can totally change the meaning of the sentence. For example, there is a difference between through and threw. In the case of genes, poor spell checking could result in new meaning for an old genetic sentence. This lead sentense could change the meaning of the rest of the paragraph.