The first cell on the earth is believed to form from the accumulation of Inorganic& Organic compounds. If we assume that this is true we see the prokaryotes have the cellular organisation but without any membrane bound organelles and no nucleus, but they have the genetic material.
I wonder from where did the genetic material come. It is my hypothesis that the donor of this genetic material may be the virus. Actually it sems to be absurd that although we know that virus can become living only when inside a living cell which has a genetic material. But I think that it may be possible that due to presence of certain matrix proteins in the cell wall of certain prokaryotes ,which acts as phage receptor might have allowed the phage to enter into the cell which is already devoid of any genetic material.
This virus seems to be an RNA virus because the evolution of the genetic material seems to be from a single strand to a double strand . This RNA produced a DNA which again by transcription produced a RNA and finally protein as ribosomes are assumed to be present in the cell cytoplasm during organic accumulation. Mainly two RNA strands were produced one involving in protein synthesis and the other remaining to be replicated and transferred to the next cell. The evolution of the single stranded RNA to double stranded DNA mainly occured to reduce the consumption of energy rich molecules like ATP,GTP,CTP,UTP. These were used in double amount initially first to produce DNA from RNA and again RNA from DNA. Thus in new generation of cells DNA became the primary genetic material.
I would like to know whether you think that this may be the fact or any other related theories may be responsible. Please reply.
(edited to format paragraphs and put spaces after periods.)
This message has been edited by AdminNosy, 11-03-2004 10:12 AM
This message has been edited by judhajeetray, 11-15-2004 05:58 AM
Sir,It is my pleasure that you have read my theory and replied soon . I would like to inform you that is my own concept which i think to be possible & I would await for any further highlighting on the subject from you as well as from any interested member.I would try to send you a well formatted note on this title soon.
[qutoe] wonder from where did the genetic material come. It is my hypothesis that the donater of this genetic material may be the virus. Actually it sems to be absurd that although we know that virus can become living only when inside a living cell which has a genetic material. But i think that it may be possible that due to presence of certain matrix proteins in the cell wall of certain prokaryotes ,which acts as phage receptor might have allowed the phage to enter into the cell which is already devoid of any genetic material.[/quote]
It does sound absurd, but it is still a very interesting idea.
This hypothesis, as I understand it, requires three things:
1. A self replicating virus.
2. Protocells made up of a lipid membrane containg proteins or peptides.
3. Viral genetic material taking over replication in the protocell.
The first hurdle, a self replicating virus, is perhaps the hardest step. At this time, the most probable scenario would be catalytic RNA, RNA that is able to carry out enzymatic processes similar to proteins. This has been observed, but usually this involves the manipulation of other RNA or nucleotide molecules. I have yet to hear of an RNA organising molecules that could create any type of viral capsid, but the possibility is there. Also, the virus would need to replicate it's RNA. It seems to me that replicating RNA in a protocell would be a more direct approach and more probable.
The second hurdle is pretty easy. Protocells can be created on your stovetop, for example. The hard part is the proteins and peptides contained in the protocells. These become important in the next step.
The third hurdle. This one ties with the first hurdle for level of difficulty. The protocell must have the right chemical makeup so that it reacts with the incoming viral genetic material and results in true cellular clonal reproduction. So we have a set of RNA's that are adapted to replicating itself and probably constructing capsid walls with amino acids. Now that RNA has to switch over to creating enzymatic proteins instead of capsid proteins. I am not sure this could occur very easily. However, nature has ways of doing the seemingly impossible, so I can't discount it.
Overall, I would say your hypothesis is less probable than other theories out there. Of course, this is a subjective opinion and shouldn't be taken as gospel truth (pardon the pun). If I understand your hypothesis completely there are several hurdles that would be easier to accomplish without going through a viral vector.
Even though Loudmouth gives some of the things needed to produce a sing celled life form, he grossly underestimates the situation when he states what is necessary for life to come into existence.
I will give you an example. My Niece, a few years ago, was helping me make a cake from a recipe book. We had all of the ingredients, in the right proportions; however, my niece failed to mix the stuff in the right order. Needles to say the cake did not turn out correctly.
My point here is this: To assume that the right ingredients accidentally fell in the right proportions at just the right time in just the right order requires more faith then theory.
I mean, take the cake example. You have, what, about eight ingredients. If you leave one ingredient out, or have to much or to little of one, or (like my niece) you mix them wrong youâ€™re not going to get the desired result. (And thatâ€™s not even mentioning the cooking time); Remember that is an intelligent agent, working from a recipe. Youâ€™re trying to figure out how a far-more-complex system came into existence without an intelligent agent.
Remember here we are talking about something â€˜not-aliveâ€™ becoming something that â€˜is-aliveâ€™; and they say my faith is blind;-}
Needles to say the cake did not turn out correctly.
Actually, your cake turned out perfectly. You could have left out a variety of ingredients, or add various ingredients (but perhaps not those needles) and mixed them in any order and your cake would still have turned out "correctly". That is, it would have been edible and nutritious - it just wouldn't have been what you and your niece happened to be expecting. But nature has no such expectations. It just does what it does and if something it happens to do is capable of reproducing somewhat similar copies of itself (a la crystals, rain drops, etc.) and is able to evolve into more fecund forms, then you have life. Evolvability is actually the simplest step - all it takes is the ability to undergo random variations of its various parameters and selection, which is just the statistical law of averages, will do the rest.
Exactly which ingredients do you speak of. The first life? please give us a definition of what you think constitutes life and what is required in order for that definition of life to exist?
I'd say that one should start out with all the amino acids and necessary peptide bonds to make a single protein. You might have better odds for a straight flush playing with 30,000 decks of cards, but with only one Ace, King, Queen, Jack, and 10 cards available in the entire deck.
Edited by Nemesis Juggernaut, : typo
â€œThis lifeâ€™s dim windows of the soul, distorts the heavens from pole to pole, and goads you to believe a lie, when you see with and not through the eye.â€ -William Blake
We've known about the abiogenetic production of peptides for 30 years, Juggs.
Miller, S. L. & Orgel, L. E. The Origins of Life on the Earth (Prentice Hall, Englewood Cliffs, NJ, 1974).
Fox, S. W. & Dose, K. Molecular Evolution and the Origin of Life (Dekker, New York, 1977).
We've known about self-replicating peptides for over 10 years.
Severin K, Lee DH, Kennan AJ, and Ghadiri MR, A synthetic peptide ligase. Nature, 389: 706-9, 1997
Lee DH, Granja JR, Martinez JA, Severin K, and Ghadri MR, A self-replicating peptide. Nature, 382: 525-8, 1996
Since you don't have access to these journals, here's a sample:
The production of amino acids and their condensation to polypeptides under plausibly prebiotic conditions have long been known. But despite the central importance of molecular self-replication in the origin of life, the feasibility of peptide self-replication has not been established experimentally [3-6]. Here we report an example of a self-replicating peptide. We show that a 32-residue alpha-helical peptide based on the leucine-zipper domain of the yeast transcription factor GCN4 can act autocatalytically in templating its own synthesis by accelerating the thioester-promoted amide-bond condensation of 15- and 17-residue fragments in neutral, dilute aqueous solutions. The self-replication process displays parabolic growth pattern with the initial rates of product formation correlating with the square-root of initial template concentration.
You might have better odds for a straight flush playing with 30,000 decks of cards
While a deck of cards has 52 individual, unique cards, there are only 20 individual amino acids used by living things. And it's unclear as to whether or not the "minimal organism" requires all 20; I think it's been estimated that an organism could carry out all the metabolic processes of life using a subset of only (I think) 12 different amino acids.
How realistic is Miller and Robertson's assertion that tidal pools can produce all four of the building blocks, or nucleotides, for RNA molecules? First, they admit in their discovery paper that the "simulated early earth conditions" under which the other two building blocks of RNA molecules, adenine and guanine, were synthesized required freezing conditions rather than near boiling conditions.7 Thus I surmise that we cannot expect the same pool to make all four of RNA's building blocks. Nor is it reasonable for two pools in close proximity to make all four, plus the necessary sugars. Nor is it reasonable for a nucleotide-rich pool to be undisturbed long enough under the right chemical conditions for the four RNA nucleotides to begin to self assemble-and to link with only right-handed ribose molecules, as life requires.
For God so greatly loved and dearly prized the world, that He [even] gave up His only begotten (unique) Son, that whoever believes in (trusts in, clings to, relies on) Him should not perish (come to destruction, be lost), but have eternal (everlasting) life.
For God did not sent the Son in to the world in order to judge (to reject, to condemn, to pass sentence on) the world, But that the world might find salvation and be made safe and sound through Him.