Abiogenesis is a reasonable theory for the beginnings of life

I'm certain that we will have a good discussion. Before I launch into it, I want to set a more solid idea of the burdens in this debate. We are discussing whether abiogenesis is feasible. As I began this debate, it is my burden to prove that there is a decent likelihood of this being the case. I will leave it up to the voters to decide whether I have proven this reasonable likelihood given my argumentation and Con's responses, rather than setting a specific numerical representation of that likelihood as a threshold to meet. But this requires that everyone be on the same playing field when it comes to what abiogenesis means and how it can be satisfied. It is "the supposed development of living organisms from nonliving matter. "[1] As such, we are describing hypothetical processes by which this scenario could have occurred, something we cannot yet know for certain as we have not discovered time travel nor have we reproduced this process fully in any laboratory setting. We do, however, know that, at some point in the past, life started on Earth, somewhere over its 4.5 billion year history as a planet, something that requires explanation. As we are discussing the transition from nonliving to living, we should define these two states, though there is some uncertainty here. This is a difficult question, one scientists are still struggling with. Definitions widely differ, but one of the best I've found is "the condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally. " (. http://dictionary.reference.com...) But even this is generalized, and it's difficult to be certain where the separation lies. Are viruses, many of which are composed of a single nucleic acid and a protein coat, considered life? They modify the metabolism of cells they infect and reproduce using their machinery, and though they certainly adapt, could we reasonably call them life? I think we can agree that a single nucleic acid associating with a protein, however, is not a threshold for the beginnings of life, at least in terms of this debate. Instead, we will assess whether an organism with its own metabolism, an ability to reproduce itself, and the capacity to adapt could come from matter that lacks one or more of these traits. So how do we get from nonliving to living? Several theories are presently being explored, many of which aren't mutually exclusive, allowing for multiple theories to explain this progression. The building blocks of life as we see it today are relatively straightforward " DNA, RNA and protein play integral roles in almost every organism we would consider to be living. However, this is not to say that the first living organisms of the world contained all three. In fact, as I will argue, they would only have required one: RNA. The reason this is possible is because the roles of RNA are highly varied. RNA can function as an enzyme, in information storage, and can affect protein expression. These widely varying functionalities, I will argue, provide a basis for life that would exist without the presence of either DNA or protein. 1. RNA functions RNA must carry many of the properties we associate with enzymes if we are to accept that it can function in a world without them. These include replication and catalysis of chemical reactions. Self-replication is necessary for a certain functional RNA to predominate, while these chemical reactions are necessary in order to generate more of the building materials for this replication. There are actually many examples of these today. Self-replication has been shown to be possible with RNA sequences that are only 165 bases long, and high fidelity only required 14 more bases, meaning that exact copies could be made of the RNA sequence. [2] These could even perform primer extensions, making it possible for these RNAs to replicate other sequences. [3] The catalysis of chemical reactions, which can enhance the creation of molecules that are the building blocks for more RNA molecules, have also been revealed to be a function of some short RNAs. [4][5] However, it doesn't stop there. As proteins did eventually come from RNAs, there has to be a method by which proteins could form using just RNA. rRNA and tRNA, both of which currently persist in all living cells, are mainly responsible for the formation of the peptide bonds that make protein possible [6][7], as well as catalyzing the transfer of amino acids that make up a given protein. In fact, it is believed that amino acids may have only functioned as cofactors, enhancing or diversifying their enzymatic capabilities, before rRNAs made it possible to form the peptide bonds that made the first proteins possible. [8] As an information storage vehicle, RNA bears many similarities to DNA, and is capable of storing information by the same means. It can even form a double helix with DNA [9], and is used by many viruses as their sole source of genomic material. In many cases, the RNA is all that is required for transmissibility. [10] In the case of viroids and satellite RNAs, which don't even have the protein coat found in viruses, RNA is their sole component, and the proteins necessary for their replication are recruited from other sources. [11] This proves that RNA is capable of storing consistent information. 2. The formation of RNA is simple and reproducible None of those functions matter if the RNA cannot form in a world without proteins. In order to prove this, I must provide evidence that nucleotides can form in the absence of enzymatic activities, and that those nucleotides can assemble into RNA strands. So let's get into nucleotide assembly. Though the yield is low, abiotic conditions utilizing simple organic compounds in the correct orientations have been proven to produce nucleotides. [12] Formamide specifically, the simplest naturally occuring amide, is a very effective starting material for their production. [13] Studies have shown that conditions early in the history of his planet could have led to the synthesis of pyrimidine ribonucleotides in the absence of free ribose, meaning that the various nucleotides could indeed have formed even without the abiotic synthesis of ribose. [14] How about assembly? In this case, studies are definitive. Nucleotides have been shown to self-assemble in water without any energy input. [15] There are also other methods by which these have been performed which require a number of other inputs. [16][17] 3. Why this matters What we are discussing here is whether life could have gotten its start in any form from nonliving materials. If, by the end of this debate, I have proven beyond reasonable doubt that a) RNA and simple organic compounds are sufficient for life to form and persist, and b) RNA and its components were possible without protein, then I will have proven that RNA is sufficient for the formation of life. As my opponent is likely to argue about the likelihood of protein formation, he will also have to provide reasons why RNA is not sufficient for life, though I will still address all arguments along these lines. 1. . http://www.thefreedictionary.com... 2. . http://www.ncbi.nlm.nih.gov... 3. . http://www.sciencemag.org... 4. . http://www.cell.com... 5. . http://adsabs.harvard.edu... 6. . http://adsabs.harvard.edu... 7. . http://www.amazon.com... 8. . http://www.cell.com... 9. . http://nar.oxfordjournals.org... 10. . http://www.sciencedirect.com... 11. . http://www.pnas.org... 12. . http://www.nature.com... 13. . http://www.ncbi.nlm.nih.gov... 14. . http://140.123.79.88/ ~neige7675/page_3. files/Chap. %203/reference/Physics%20of%20Life%20Reviews%209%20%282012%29%2084%A1V104. pdf 15. . http://www.jbc.org... 16. . http://pubs.acs.org... 17. . http://www.ncbi.nlm.nih.gov...