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26

In 2010, Dr. Craig Venter actually used a bacterial shell and wrote DNA for it. Scientists have created the world's first synthetic life form in a landmark experiment that paves the way for designer organisms that are built rather than evolved. (Snip) The new organism is based on an existing bacterium that causes mastitis in goats, but at its ...


21

In principle it is possible. Life doesn’t contain some divine or intrinsically spiritual element that we would have to add to our artificial organism potion to breathe life into it. At this moment we are limited by gaps in our knowledge and by the current state of technology. We first have to better understand fundamental principles of life on a ...


18

Origin of Life: Chemical Approach is an edited volume by Piet Herdewijn and M. Volkan Kisakürek. here is the book's description from the webpage: Dedicated to the fond memory of two great pioneers of this science, Leslie E. Orgel and Stanley L. Miller, this compilation of reviews and original manuscripts provides an overview of the current state of the ...


17

I know that you are referring to the commonly ribosome-translated L-proteins, but I can't help but add that there are some peptides, called nonribosomal peptides, which are not dependent on the mRNA and can incorporate D-amino acids. They have very important pharmaceutical properties. I recommend this (1) review article if you are interested in the subject. ...


16

The ribosome holds the peptide-bound tRNA and aminoacyl-tRNA in the right orientation to catalyze the peptidyltransferase reaction. http://www.pnas.org/content/103/36/13327/F1.expansion.html If the incoming aminoacyl-tRNA was the other enantiomer, the amino acid moiety would not fit properly into the ribosome active site. In other words, the shape of the ...


14

The fascinating field of abiogenesis is, as Nick Lane put it, "a wild west of ideas, theories, speculations, and even data". The stories we have involve a plethora of assumptions, there is no hypothesis where all or most of the pieces would fit together. Usually scientists agree it was RNA that played central role in the process, as the molecule could both ...


14

I would like to add a lecture on Synthetic Biology by Andrew Hessel, who introduces the open source synthetic biology field, compares it to computing, and gives an overview of what are its applications, like the creation of the first synthetic organism. I also stumbled upon a talk from the famous physicist Michio Kaku, who shares his vision about the world ...


10

I think the issue with Intelligent Design is not so much that its patently proven wrong. On the contrary, the problem is that it not a scientific hypothesis and so it really isn't a scientific question. If I may, the basis of the scientific method, as formulated by Karl Popper, but commonly in use today, is that science is the putting forth of theories ...


10

Evolution or (as Darwin called it) "descent with modification" is a theory which explains the origin of the species NOT the origin of life. How the first life arose is completely irrelevant to the theory of evolution. What evolution does explain is how and why we have such variety of life on earth all descending from the same organism. What you're asking ...


9

As far as I know, it is unknown why we only see left-handed and not right–handed amino acids. A recent article speculates that the weak force could be responsible for a tiny asymmetry in energy levels between the stereo-isomers. However, if the effect is tiny, its hard to see why it should have biological implications. In 2004, Tamura and Schimmel showed ...


9

The posts above seem very thorough and complete, but I'd like to add by linking to this TED talk, as well as this one, for you to familiarize yourself with Craig Venter's work on synthetic life. Enjoy!


9

I quite like the account given in Early evolution without a tree of life, where alkaline hydrothermal vents (like "Lost City") are theorized to have formed pre-biotic compartments with a proton gradient (i.e. an energy source) from which cells could have evolved.


7

From a more geology-oriented perspective: Robert M Hazen (2007) - Genesis: The Scientific Quest for Life's Origins Noam Lahav (1999)- Biogenesis: Theories of Life's Origin J William Schopf (2001) - Cradle of Life I have watched Hazen's nice "Origins of Life" DVD/Video Course. There he says that the Miller-Urey stuff has gotten less popular. Their ...


7

The normal results of an attempt to assemble proteins with mixed chiral amino acids is a protein that fails to fold. The general assumption due to this result is a choice has to be made very early on to use all right-handed or all left-handed amino acids. There doesn't seem to be any particular reason to choose one way over the other except for prevalence.


6

We don't know how self-replicating molecules first arose (and probably never will know exactly) but the Earth is large and had 500 million years (i.e. the prebiotic Earth timescale) or so to experiment in organic chemistry. The land-sea interface (such as tidal pools) are a good candidate site since these are areas where high concentrations of organic ...


6

It may never have happened again, however, since all lifeforms on Earth today are similar on a molecular level (DNA), suggesting a common origin. An important distinction to make here is that all extant life on Earth has a common origin. It's completely possible that abiogenesis occurred many times, but whatever organisms emerged as a result became ...


5

What you are possibly thinking of is large versions of the Miller Urey Experiment where a mixture of reducing gasses carbon dioxide, ammonia, nitrogen and the like are subjected to electrical arcs in a closed flask reaction, resulting in some biological molecules being produced. Opinions have changed - Miller Urey did get the atmosphere wrong and so their ...


5

Well, what you seem to be suggesting is "Did life evolve twice on Earth?" Your original question has an answer: Probably yes. It's not unlikely to think that the original cell evolved into two different paths and then one went extinct. However, that doesn't address LUCA. If we found fossil evidence of what we thought was LUCA, and then fossil evidence that ...


5

An interesting take on this question is addressed in Bokov and Steinberg's hypothesis. They have proposed the ribosome has evolved from a short length (~110bp) of RNA that did not have the translational activity that we associate with ribosomes today. Instead this short length of RNA carried out alternative functions on RNA in RNA based life. Then ...


5

They teach us in Physics that the entropy of an isolated system is always increasing or at least constant. Then how can an organism be born under these conditions? The sun sends energy to the Earth, allowing for a decrease in entropy on Earth at the expense of the sun's entropy. But when I think about it, all of them assume that there was an ...


5

This is an interesting question, particularly considered in the context that Cairns-Smith (1985) even suggested that clays (silicates in solution) may have had some sort of early selection acting on them due to their surface chemistries. However, there are a number of major problems with Silicon. Some are chemical and some are astrophysical in nature. For ...


5

It is interesting to note that, in the Wikipedia article, it states that The amino acids were racemic (that is, the chirality of their enantiomers are equally left- and right-handed), indicating that they are not present due to terrestrial contamination". This implies that, if a 'life form' did create these proteins, they are fundamentally quite ...


4

I think it's fair to say that we don't really know how these more complex organic molecules formed abiotically, but we can say that carbonaceous chondrites - a class of carbon and organic molecule bearing meteorites to which Murchison belongs (specifically CM2) - have experienced at least three distinct chemical histories: In the interstellar medium (ISM) ...


4

Welcome to Biology.SE! Your question has nothing to do with evolutionary biology Evolutionary Theory does not explain the origin of life just like the Theory of Gravity does not explain the diffraction of light! In other words, explaining the origin of life is not within the scope of evolutionary biology. You should edit your title. But still, your ...


3

This is an extremely interesting and extremely fundamental question, indeed, and thus far, biologists have failed at coming up with a satisfying answer. We know that all the parts are there, we just don't know how they were arranged, or which ones go where. The question is, in essence, composed of three sub-questions: How did the fundamental building ...


3

I would say this is a question that might not be resolved yet. Going back to the earliest days of DNA - a billion years ago - its hard to imagine circular DNA being the first sort to show up. Its speculated that in the transition from RNA world to DNA world, early on each gene had a separate piece of nucleic acid coding for it which would not have been ...


3

It is hard to give an answer to this question that is not just speculation. We can be reasonably confident that the most recent common ancestor of bacteria and archaea had circular genomes. However, we currently have no way to get any conclusive evidence earlier than that. 3 billion year old DNA doesn't fossilize. So it's just speculation what DNA looked ...


2

While many point to RNA, or a variant of it, as being the first molecule of "life" very few people know where it came from. Some suggest that it came from outer space because it's uncertain how the material for sugar-phosphate backbones could have developed on earth and that the perhaps these materials found their way here via meteorites. There are several ...


2

If there are enough nutrients, a unicellular organism will "eat" and grow until it reaches a certain size. Through different mechanisms, it can sense that it is large enough and has enough metabolites to divide. Then, the organism will duplicates its DNA, separate the duplicated DNA and divide. (This is called fission for prokaryotes.) So why does it ...


2

It may never have happened again, however, since all lifeforms on Earth today are similar on a molecular level Actually, the similarity is at the chemical level where the chirality of all known-life's amino acids are "left-handed" (see http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Alternative-chirality_biomolecules). Since there is ...



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