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Every living thing on Earth depends on a mysterious tangle of molecules called ribosomes.

These are the cell's protein factories, translating the genetic information in DNA into an amino acid sequence to create proteins.

Scientists believe that the ribosome - whose history is difficult to track - holds clues to how the first molecules of life came together around four billion years ago.

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In a new study, scientists compared three-dimensional structures of ribosomes from a variety of species of varying biological complexity, including humans, yeast, bacteria and archaea. The researchers found distinct fingerprints in the ribosomes where new structures were added to its surface

Now researchers are a step closer to uncovering these clues after modelling the evolution of these biological factories in unprecedented detail.

The core of the ribosome is essentially the same in all living systems, while the outer regions expand and become complicated as species gain complexity.

By digitally peeling back the layers of modern ribosomes, scientists at Georgia Institute of Technology in Atlanta were able to model the structures of the very first of these biological factories.

'The history of the ribosome tells us about the origin of life,' said Loren Williams, a professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology.

'We have worked out on a fine level of detail how the ribosome originated and evolved.'

Humans have the largest and most complex ribosomes.

'But the changes are on the surface – researchers found the heart of a human ribosome is the same as in a mould ribosome.

Pictured are ribosomes from the salivary gland of an insect. Ribosomes are the biological superstructures that translate genetic information into proteins.These small biosynthetic factories convert the DNA genetic information into an amino acid sequence – which is the primary structure of proteins that make up our body

'The translation system is the operating system of life,' Professor Williams said. 'At its core the ribosome is the same everywhere. The ribosome is universal biology.'

The study compared three-dimensional structures of ribosomes from a variety of species of varying biological complexity, including humans, yeast, bacteria and archaea.

The researchers found distinct fingerprints in the ribosomes where new structures were added to the ribosomal surface without altering the core.

The research team worked the process backwards in time to generate models of simple, primordial ribosomes.

'We learned some of the rules of the ribosome, that evolution can change the ribosome as long as it does not mess with its core,' Professor Williams said.

'Evolution can add things on, but it can't change what was already there.'

Hundreds of thousands of ribosomes work in each living cell. For example, quickly replicating cells, such as liver cells, may contain a few million ribosomes. Even bacterial cells may contain up to 100,000 ribosomes. Ribosome (pictured) can be found in different parts of a cell