Dan Linton

DNA To Protein - Part 1 I’m starting a short series to go over the basics of how DNA works and is ultimately translated into a protein. If you have no background in science, no worries, I will keep the description conceptual and easy to follow. 🤓 So, here’s the first installment… The blueprints for life are contained in a molecule called DNA. In the 20th century, scientists learned about the structure of DNA and its purpose, but only in the latter half of the century did it become obvious that DNA is built on a language. Scientists eventually learned how the cells translate this language into action. The basics of the alphabet, how words are formed, how sentences are formed, and how this information is used to control the cell became more apparent as complex experiments were conducted. In this segment, I will discuss some of the rudimentary aspects of this language. The alphabet consists of 4 letters. These letters are actually the representation of 4 different molecules that are used to construct DNA called nucleotides. The 4 letters are A, T, C, and G. The entire human genome consists of 3 billion of these letters strung together. We now know this entire sequence of letters for humans, and for many other organisms. These 4 letters are combined together in a linear sequence to form words. Unlike a spoken language, words come in only one size in the language of DNA. Words in DNA are comprised of only 3 letters. So how many different words does this language allow for? The answer is simple. 4 letters combined in groups of 3 allows for 64 different words. A word in the language of DNA is called a “codon”. So, there are 64 different codons. AAA AAT AAC AAG AGA AGT AGC AGG …………………. So on and so forth. These 64 different codons are then strung together in a series to form a sentence. A sentence is called a “gene”. A sentence has a beginning, and an end. The beginning of the sentence is the Start Codon, ATG. The end of the sentence is the the Stop Codon, which can be one of 3 different codons: TGA, TAA, or TAG. Humans have about 25,000 of these “sentences” (or genes) scattered throughout the 3 billion letters of the human genome. The length of a sentence or gene can be any length. Some genes encode a sentence that is 50 codons/words in length, and some genes encode sentences that are thousands of codons/words in length. But they all have a beginning and an end. Just like a sentence starts with a capital letter and ends with a period, the language of DNA calls for a start codon to begin a sentence, and a stop codon to end a sentence. Now, the sentences/genes don’t account for all of the 3 billion letters of DNA. In fact, the great majority of DNA in humans is DNA that exists between the genes. Scientists used to call this DNA “junk DNA” because they thought it was useless, but they now know that it serves a very important purpose. We will discuss this in a future segment. That’s all for now because I don’t want to overwhelm you with too much information in one sitting. We’ll take it a step at a time. In the next segment, we will take a look at the meaning of the 64 different words. If you find value in the articles I write, please “like” and retweet. I appreciate it greatly. :-) Stay tuned for the next segment.