Which came first, the chicken or the egg? This question has puzzled scientists and curious citizens alike for many years.
“The problem of the origin of life remains one of the deepest mysteries surrounding evolutionary molecular biology,” says Aashish Priye, University of Cincinnati assistant professor of chemical engineering.
Priye argues that the real question we should be asking ourselves is, which came first, the DNA or the protein?
DNA and proteins are the “fundamental machinery of life,” says Priye, and each plays an essential role. DNA stores genetic information and instructions to construct proteins. To be passed onto the next generation, however, DNA molecules have to be replicated through proteins. Together, DNA and protein form the simplest sustaining system of life.
So, which came first, the DNA or protein?
The answer may lie in RNA, which is similar to DNA in that it’s a life-based molecule that can store information. Unlike double-stranded DNA, however, some RNA molecules can self-replicate without proteins.
The idea that RNA was the first molecule on Earth isn’t new, but some gaps prevent a complete theory from forming around this.
“How we got from the basic organic building blocks to more complex biomolecules, such as an early form of RNA, is still an open question,” says Priye. “These building blocks were dispersed in dilute concentrations in the ocean, and there had to be a driving force to concentrate them to levels under which they can polymerize into more complex biomolecules.”
That’s where Priye’s research into microscale fluid mechanics comes in.
Priye’s lab studies how fluids behave when they are confined in small enclosures with changing temperatures. Priye compares the resulting flow to the flow in lava lamps, where fluid in a cylindrical enclosure is heated from below. These types of flows are universal in nature, but at the micro-scale, these flows can greatly accelerate molecular transport and reactions.