October 22, 2013
Teaching Bacteria How To Read
There are an incredible amount of languages in the world today. The Linguistic Society of America mentions that as of 2009, there are 6,909 distinctly classified languages. That gives me a headache just typing it. Linguistics can be messy and unreliable. They are difficult to quantify, constantly evolving, and often mean a multitude of things.
However, the language of biology is much simpler. An organism’s genetic information is housed in their DNA. DNA is written in a four-letter language: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). Those four letters are arranged into base pairs, which are read in groups of three. This triplet system allows for 64 different arrangements, or “words.” Despite the possibilities, only 20 different arrangements are used in the body to form amino acids and proteins.
Why are only 20 amino acids used? Could we rearrange a few things and make new amino acids that perform different tasks in the body? What are the implications of these changes? Can we manipulate this “universal code” to make it say what we want? These are questions that researchers began to ask.
April Flowers of redOrbit explains in her article Plug And Play Synthetic Biology – Rewriting an Entire Genome, how researchers from Yale and Harvard attempted to expand our biological language. The goal of their study was to “[expand] on nature’s handiwork by substituting different codons or letters throughout the genome and then reintroducing entirely new letters to create amino acids not found in nature.”
Let me translate that for you. Researchers “wrote” new genetic words and “taught” the E. coli genome how to read them. They successfully altered the original DNA-ese. After playing with this single “word” (technically called a codon), researchers tested 13 other codons and found that they could also be substituted. They more or less played Scrabble with the E. coli genome.
So, why is this process interesting? (Besides the fact that we are essentially WRITING DNA.) Well, biotechnology often relies on the manipulation of bacterial genomes to produce different biological products. A classic example is the production of artificial insulin. A laboratory (non-disease causing) strain of E. coli is actually manipulated to produce the insulin hormone that is used to treat diabetes.
Introducing new letters and amino acid combinations into the world of biotechnology could open a lot of doors for disease treatment. For example, bacteria could be altered to produce therapeutic molecules of polymers that could function in the human bloodstream.
Basically, the ABCs of DNA could possibly be manipulated. The unbreakable rule, something along the lines of “the double helix is composed of base pairs of adenine, guanine, cytosine, and thymine” has been broken. In the future, scientists could develop their own codons, or “words,” to insert into genomes for various purposes. Genomes could be literally “built” by biotechnology; we only need to improve our bacteria’s educational system. No E. coli left behind!
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