The oldest question in the book, did life existed before there was nucleic acid. Researchers have now provided evidence of primitive biochemistry occurring without phosphate which is an essential component of the building blocks of out genetic chemistry, then giving more weight to the argument that before there was life, there was metabolism.
The researchers both from the MIT and Boston University, are the team responsible and have identified a number of previously unknow metabolic pathways that are not at all dependent on phosphate, and this can change the way we understand how complex organic chemistry evolved into life on Earth.
Life, as we define it today, is hugely based on imperfectly replicating chemistry, which requires a template that can be copied and the means to capture enough energy to turn simple carbon-based chemicals into more complex forms.
In the RNA-world hypothesis, strings of free-floating ribonucleic acid (RNA) facilitated processes that we can describe as precursors to life, with the polymer taking on the roles of both an early kind of information template and chemical machinery.
One problem with this, is that RNA can’t work without an energy source, which requires a sequence of chemical reactions that resembles an early form of metabolism. And the RNA molecule also includes phosphate, a molecule that was locked up tight in the environment and was therefore difficult to incorporate into organic compounds.
Another ‘pre-life’ theory suggest early forms of metabolic chemistry were already absorbing energy from the environment, in the form of heat or light and transferring it between chemical reactions in an organic soup. After a while the primitive metabolism became coupled with the RNA.
“The significance of this work is that future efforts to understand life’s origin should take into account the concrete possibility that phosphate-based processes, which are essential today, may not have been around when the first life-like processes started emerging,” said researcher Daniel Segrè from Boston University.