The Essentials: ATCG – The ABC’s of DNA

From courtroom dramas to disturbing episodes of Dateline NBC, DNA has entered into the public vernacular. There has been a huge popularization of the genetic molecule in the last 20 years or so but I’m not sure how much the general public really knows about DNA.  I really don’t know. 

In my mind when I hear terms like base pair, nucleotide, nitrogenous bases, codon, intron, exon, DNA, RNA, mRNA, tRNA, rRNA, central dogma, transcription, translation, polymerase, peptide bonds, ribosome, etc. (as in etcetera) I am transported to the early days of my biology education when I first fell hard for science.  I realize that for many people these words might insight a different response, something a little closer to, “Nucleowho? Ribowhat?”  

Advancements in our understanding of DNA have impacted many areas of our lives including our understanding of evolution. While DNA can bolster the evidence for evolution in many ways it can’t make a case if it is incomprehensible.  

One of the big challenges with science is that the technical language can be a big barrier.  In my Essential Cell Biology textbook the authors disambiguate any confusion about ribosomes with the helpful section heading “The Ribosome is a Ribozyme”. Thanks authors, that clears everything up. Before I describe how DNA supports the case for evolution I’ll explain a few key ideas that will help later on.

DNA – DNA is the molecule that stores all of the information for making and running living things.  Like all molecules DNA is made up of smaller parts.  The main structure of DNA is like a ladder.  The rail of the ladder is made up of alternating phosphate and sugar molecules.  The rungs of the ladder are made up of nucleotides which extend out from each rail and meet in the middle.  The ladder is twisted which gives DNA its famous “double helix” shape.

Nucleotides – Nucleotides are the functional part of DNA and are the “coding” elements of the molecule. There are only four different nucleotides in DNA. This might not seem like enough to create all of the instructions for making and controlling a life but the possibilities for complexity are astounding. If you think of binary code, the basic computer language which uses combinations of 1 and 0 to code for everything ever done on the internet or a computer, you can see how four “digits” could create an incredibly complex message.  The nucleotides that create the DNA code are indicated by the letters ATCG (Adenine, Thymine, Guanine and Cytosine).  A,T,C and G are refered to as bases.

To see an example of the two digit binary code in action copy the sequence below and paste it into the converter at this link.  There may be a bonus in it for you as well.

010000100110100101101110011000010111001001111001001000000110001101101111011001000110010100100000011101010111001101100101011100110010000001110100011101110110111100100000011001000110100101100111011010010111010001110011001011100010000001000100010011100100000100100000011101010111001101100101011100110010000000110100001000000110010001101001011001110110100101110100011100110010111000100000010000110111001001100001011110100111100100100000011100100110100101100111011010000111010000111111001000000100010101110110011001010111001001111001011101000110100001101001011011100110011100100000011011110110111000100000011000110110111101101101011100000111010101110100011001010111001001110011001000000110111101110010001000000111010001101000011001010010000001110111011001010110001000100000011000110110000101101110001000000110001001100101001000000110001001101111011010010110110001100101011001000010000001100100011011110111011101101110001000000111010001101111001000000011000110010010011100110010000001100001011011100110010000100000001100001001001001110011001011100010000001001001011011100110001101101100011101010110010001101001011011100110011100100000011101000110100001101001011100110010000001011001011011110111010101010100011101010110001001100101001000000111011001101001011001000110010101101111001011100010000000100000011010000111010001110100011100000011101000101111001011110111011101110111011101110010111001111001011011110111010101110100011101010110001001100101001011100110001101101111011011010010111101110111011000010111010001100011011010000011111101110110001111010101001001101010001011010110111101101011011101100100110001001101001100110110011101010101