He had heard through friends that I am an atheist (according to him, this is synonymous with devil worship, and he wished only to save me from an eternity in hell.) We proceeded to have a half-religious-half-philosophical conversation discussing the bible, stoicism and how misguided I am, but that's a story for another entry.
Something he said to me really piqued my interest, as I could not figure out where he got the information from. In context, he was attempting to debunk not only our current evolutionary theory, but evolution in its entirety and the possibility of abiogenesis.
Odds of a strand of DNA arranging itself in the right order to create life? 1 in 10^400,000. About the same as YOU winning the lottery EVERY DAY for 15 Billion consecutive years. Good luck.
As a scientist, I could only stare blankly into the screen at a loss for words. Is this really what people believe? How can someone believe they know the odds that the molecules that make up DNA will form a DNA strand that creates a living organism?
There are only four chemicals that make up the nucleotides of deoxyribonucleic acid, the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms. A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine. Each gene's code combines the four chemicals in various ways to spell out 3-letter "words" that specify which amino acid is needed at every step in making a protein. Every single living organism has DNA, and every single one is made up of A, T, G and C. How these are arranged; and how many base pairs there are tell us what organism it is, and essentially becomes the blueprint of the organism, instructing the cells what to do. This blueprint is read by transcribing stretches of DNA into the related nucleic acid RNA.
A - T and G - C form a non-covalent hydrogen bond. What does that mean? The double helix can be broken in half and rejoined with heat or force. When all the base pairs in a DNA double helix melt, the strands separate and exist in solution as two entirely independent molecules. If the chances of DNA functioning properly was so low, why is it that we can place a centi tube with a strand of isolated DNA along with a gene from another organism in a centrifuge, give it a spin and have an organism with functioning recombinant DNA? The free floating nucleotides bond on their own to form the double helix.
The DNA between an egg and a sperm, in a human, has an estimated 91% chance of "getting it right", as it were, once fertilization occurs at arranging correctly to form another human. If you take into account genetic variation from sexual recombination, the number of possible combinations of DNA for the resulting offspring is astronomical. Our entire genome has upwards of 3.3 billion base pairs. If we consider that we have no way of knowing which base pairs will separate and which single strands will connect to which genes, the actual possible combinations is innumerable. If under the conditions in a zygote, the nucleotides bond around 91% of the time in a combination that is correct for a functioning human, the odds he has stated seem highly incorrect.
We know that DNA copies itself within an organism, and we know that small mutations occur in
each copy, which, in part, attributes to the variance among one species of organisms and the continual differences that increase exponentially from generation to generation. This is why a new organism doesn't form in utero, within our cells or any other DNA duplication process. It would seem that organisms either evolved over a substantial period of time from other organisms and/or molecules came together under certain conditions to begin the life of a new organism.
What else do we know? We know that we have a record of about 1.4 million species of living organisms. In a famous study conducted in Panama, 19 trees were "fogged" with insecticide and the dead were collected as they fell through the canopy. In this study, nearly 1,200 species of beetles alone were collected. Of those, 80 percent were not known to science. While it may be dangerous to extrapolate numbers like these to other places, it gives at least a high estimate of the number of species that could exist on earth - that high estimate being around 100 million species. A low estimate is 2 million. The best estimate might be around 10 million. But even if that’s the case, it means we've only known about a small fraction of what is presently there.
Many of the species that we're discovering live in areas that are not often studied. Take the sea floor for instance. Hydrothermal vents along the floor provide a type of chemical energy for bacteria. These bacteria use this energy like plants use the energy of the sun. They then form
the base of a giant food web thousands of feet below the surface. It wasn't until recently have we been able to discover this new habitat. Now scientists believe there could be as many as a million species just on the ocean floor.
If we take the best estimate of number of species living or in fossil form, we estimate there have been about 10 million species. 10 million species all with the same molecules making up their DNA. However, we have no idea how many possible species there are among the seemingly infinite number of genome lengths and base pair combinations. The Amoeba dubia has about 670 billion base pairs that make up its genome, and the smallest genome length discovered of a true organism is 490,885.
The odds of a specific organism being formed under the conditions that these molecules come together is bleak; monumentally bleak. The odds of any species coming together from the infinite number of possible combinations and numbers of base pairs? Not calculable, but considering the current number of species, I would say that the odds are more than likely considerably better than what the science-debunker originally stated.
The molecules have movement and a charge that that forms a double helix shape. Many people wind up thinking that this shape is clearly the work of a God, but if they studied magnetism, they would know that the recipe for a double helix is fairly simple. A strong magnetic field (created by the molecules), rotation (also created by the molecules) and matter (the molecules.) Since we can create the fluids for engineered recombinant DNA, one has to assume that at some point, this combination of fluids (or another suitable liquid) will be present on Earth on its own.
With the millions of species that we have recorded, all with the same molecules forming them and knowing that these bonds between base pairs form without assistance of a conscious being it should be no quantum leap to the idea that DNA forms on its own, and that the molecules that make up DNA tend to fall in an order that creates life.