On Self-doings and Copiers
In our modern, fast-paced world, we love products that promise to do things all by themselves. Who wouldn't want an oven, toilet, fish tank, litter box, and even a water bottle that cleans itself? Some life scientists also use this label of self-service, such as in "self-replication of DNA." (1)
Every time a cell has to divide, it first needs to make a copy of the genetic hard drive, the information written on DNA strands. It is called DNA replication. DNA, however, is as self-replicating as my kitchen is self-cleaning. My favorite refrigerator magnet so deftly explains, "This is a self-cleaning kitchen. Please clean up after yourself." Just like my kitchen, there is more to "self-replicating" than what meets the eye.
My kitchen merely needs organization, people, effort, and cleaning supplies to "self-clean". But the replication of the human genome requires a finely tuned signaling system, protective end caps (telomeres), billions of parts, a steady supply of energy, as well as molecular machines and repair systems. Just imagine a machine (helicase) that unwinds the DNA double helix at speeds that rival the rotation of a jet engine turbine. Or a complex copier machine (polymerase), that not only copy at incredible speeds but also proofread and help correct errors that would otherwise stall the replication machinery and cause cellular death. (2,3)
DNA replication is yet another masterpiece of microstructural engineering and design to marvel at. It started when each of us were just one tiny cell old, and continues somewhere inside our bodies all the time!
Mechanism of DNA Replication from the DNA Learning Center
1. Self-replication of DNA rings. https://www.nature.com/articles/nnano.2015.87 2. The Cell: A Molecular Approach. 2nd edition. https://www.ncbi.nlm.nih.gov/books/NBK9900/ 3. DNA Replication Fidelity. http://www.jbc.org/content/279/17/16895.full