Scientists say new evidence suggests 'we may have been wrong about the origin of life'

Scientists have found new evidence which they say suggests 'we may have been wrong about the origin of life'.

New peer-reviewed analysis has looked into exactly how genes first emerged, specifically when amino acids joined into the mix.

The study comes as we already know all lifeforms share the same genetic code - but how and when this code came about has been at the heart of some scientific controversy.

According to genetic scientists at the University of Arizona, our understanding of how this genetic code has evolved requires some serious amending.

Sawsan Wehbi and senior author Joanna Masel posed a new theory in the journal Proceedings of the National Academy of Science that the order in which amino acids, the building blocks of genetic code, came in greatly differs to the widespread scientific consensus.

The study involved amino acids (Getty Images)

Masel wrote: "The genetic code is an amazing system in which sequences of three nucleotides, known as codons, in a string of DNA or RNA are translated into protein sequences using 20 different amino acids.

"It's a mind-bogglingly complicated process, and our code is surprisingly good. It's nearly optimal for a whole bunch of things, and it must have evolved in stages."

The researchers explained that key pieces of our proteins (amino acids) stretch back four billion years to the 'last universal common ancestor' of all life on Earth.

The so-called 'last universal common ancestor' (LUCA) is the single life form that has branched into everything since.

The scientists claim prior research is outdated and flawed because it is based on laboratory experiments rather than evolution.

For instance, the old theory relies on a famous 1952 Urey-Miller experiment, which attempted to imitate early Earth conditions that likely saw the origin of life, reports Phys.org.

Scientists studied the genetic code (Getty Images)

Such experiments did not discover amino acids containing sulfur, despite an abundance of the element on Earth in its early years.

So, the belief that sulfuric amino acids joined the genetic code later on could be wrong.

Using modern technology and National Center for Biotechnology Information data, the team were able to create a tree of protein domains to the LUCA, which were not discovered until the 1970s, to propose rethinking the order in which the 20 amino acids emerged.

Wehbi explained: "If you think about the protein being a car, a domain is like a wheel.

"It's a part that can be used in many different cars, and wheels have been around much longer than cars."

The team essentially discovered that today's genetic code most likely appeared after other codes that went extinct.

They managed to identify more than 400 families of protein sequences that date back to LUCA, and more than 100 of them originated even earlier and had already diversified before the arrival of LUCA.

These sequences contained more amino acids with aromatic ring structures.

Masel added: "This gives hints about other genetic codes that came before ours, and which have since disappeared in the abyss of geologic time.

"Early life seems to have liked rings."