The winner of the chicken-egg paradox

For a while there, scientists debated on what came first, DNA or proteins. Since DNA codes for proteins, but DNA requires proteins to make more proteins (AH!), it was hard to figure out what came first. This is the chicken-egg paradox. If we were talking about actual chickens and eggs, it’s obviously the egg since dinosaurs laid eggs well before chickens evolved. But back to DNA.

DNA necklace in sterling silver

The “stuff” of life, whatever it was, needed to self replicate and mutate. While we know that DNA is probably too stable to do that, its single-stranded cousin, RNA, was most likely up for the task. Man-made short strands of RNA have even been shown to self-replicate in the lab! From here, it’s just a short biochemical leap to enzymatic properties.

Being single-stranded and all means having the ability to get your base pairs to hydrogen bond with each other. In this way, RNA folds in on itself, creating blobby, 3D structures that look and act like enzymes. We call these things ribozymes, a word that combines ribonucleic acid with enzyme. This is yet another piece of evidence that shows scientists have been on trend with name-combos way before the Brangelinas and the TomKats came around.

Over time, with more and more complex organisms evolving, DNA became the gold standard for holding onto information in a cell. Enzymes evolved and RNA now acts like an intermediary, shuttling instructions back and forth between the nucleus and the ribosome. Having said all this, we’re happy to say that we’ve made it possible for you to carry a piece of DNA with you everywhere you go. Yes, technically, you’re carrying it inside every single cell*, but with a piece like our horizontal DNA, there’s no need for detergent, ethanol, precipitates, or microscopes.

*Red blood cells and cornified cells are the exception to the rule here, they contain no DNA.

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