biodiversity

Scientists may have just found the answer to the original chicken vs. egg debate. It’s one of those evolutionary questions that has racked the minds of scientists for years: how can the first chicken be made without an egg and how can an egg be formed without the chicken? From years of studying the functions of genes within the living world, scientists may finally have more fuel for the theory that Earth was capturing energy from chemical reactions before it was replicating RNA.

The reason this question has plagued scientists for so long is because, until now, metabolism and genes seemed to have an eternally codependent relationship. We need energy to replicate genes and our metabolism is regulated by enzymes made by genes…so it seems that we can’t have one without the other; scientists are just now finding that millions of years ago, when simple cells were all that roamed the Earth, that may not have been the case.According to sciencealert.com, “There is a growing body of evidence to suggest simple forms of metabolism could have been churning away, unshackled by RNA and proteins.”

Researchers Gustavo Caetano-Anolles from University of Illinois and Ibrahim Koc from Gebze Technical University in Turkey have just discovered more evidence than ever before to add credibility to the hypothesis that organisms started metabolizing before they depended upon genes for metabolism. The most common functions, they reasoned, could be traced further back in evolutionary history than functions that developed more recently. By comparing the sequences and functions of the genes of 249 organisms, Caetano-Anolles and Koc were able to determine that metabolism and binding are common to every living organism.

Going off their findings, as well as pre-existing evidence for the “metabolism first” hypothesis, Anolles describes a likely scenario in which molecules first generated energy from metabolism in order to bind with other molecules, and then “replaced chemical reactions already going on in the planet and internalized them into cells through development of enzymatic activities.”

While these findings are not definitive, and the great debate on whether metabolism or replicating RNA came first will likely persist, they are critical for modern science because they open the door for a deeper understanding of how genes develop new functions and how they could be engineered to behave a certain way based on past functions. Research like this is imperative for piecing together the puzzling fragments describing the origin of life.

For more information on this important discovery, read the original article here.