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"In living cells, most catalysts are protein enzymes, composed of amino acids, but in the 1980s another kind of catalyst was discovered. These are RNA molecules composed of nucleotides that are now called ribozymes. /.../
For the purposes of today’s column I will go through the probability calculation that a specific ribozyme might assemble by chance. Assume that the ribozyme is 300 nucleotides long, and that at each position there could be any of four nucleotides present. The chances of that ribozyme assembling are then 4^300, a number so large that it could not possibly happen by chance even once in 13 billion years, the age of the universe.
But life DID begin! Could we be missing something?
The answer, of course, is yes, we are. The calculation assumes that a single specific ribozyme must be synthesized for life to begin, but that’s not how it works. Instead, let’s make the plausible assumption that an enormous number of random polymers are synthesized, which are then subject to selection and evolution. /.../ we can test it. /.../
After only 4 rounds of selection and amplification they began to see an increase in catalytic activity, and after 10 rounds the rate was 7 million times faster than the uncatalyzed rate. It was even possible to watch the RNA evolve. /.../ Some came to dominate the reaction, while others went extinct.
By the way, this is the same basic logic that breeders use when they select for a property such as coat color in dogs."
Read Bartel and Szostak, published in Science in 1993.
Read full column:
http://www.science20.com/stars_planets_life/calculating_odds_life_could_begin_chance
No gods, no monsters, no aliens needed.
Trying to explain the absolute impossibility of DNA occurring randomly is a nice attempt at a grasp for straws, at best.
DNA is an extremely highly specified and complex code which provides the instructions for a nano-manufacturing plant to build proteins for living cells. Proteins have a wide range of function in the cell; such as, building components of the cell to harvesting energy.
There are complex molecular machines, like the bacteria flagellum, that are irreducibly complex, meaning if one part is removed or damaged in the system then the system is either degraded or fails to function.
One example is the bacteria flagellum which is a molecular machine that operates like an outboard motor complete with a propeller, drive shaft, and u-joints. It is said to be the most efficient motor in the universe as it can rotate at 100,000 RPM and stop on a dime and reverse direction in a quarter turn.
These machines in the cells of living systems are built part by part in a nano-manufacturing plant using the code inside the DNA molecule. There are codes instructing the machine to start assembling parts in specific orders and instructing when to stop the assembly. There are spell checker type enzymes searching and correcting errors in the code, there is copying and transporting of the code. DNA has nested coding. DNA has a files within folders hierarchical structure. A senior software engineer with Microsoft once said DNA follows design strategies similar to those used by their software programmers but one far more advanced than they have been able to devise.
The specific genetic instructions to build a protein in even the simplest one celled organism would fill hundreds of pages of printed text.
Approximately 3 percent of DNA encodes protein sequences and the other 97 percent is noncoding DNA. Noncoding DNA transcribes into functional non-coding RNA molecules (like transfer RNA, ribosomal RNA, and regulator RNAs). Other functions of noncoding DNA include transcriptional and translational regulation of protein-coding sequences, scaffold attachment regions, origins of DNA replication, centormeters and telomeres. This is no longer referred to as "junk DNA." That was an old term. The noncoding DNA is more like the operating system.
Watch the 3 minute and 34 second video below on how DNA works if you are interested (there is a real good and easy to understand computer generated model showing how DNA works in this short video):
Another longer video is below: