How did early primordial cells evolve?

Four billion years ago, soon after the planet cooled enough for life to begin, primordial cells may have replicated and divided without protein machinery or cell walls, relying instead on just a flimsy lipid membrane. New research on bacteria examines exactly how these primitive cells could have evolved without such crucial structures. While the vast majority of bacteria have cell walls, many bacteria can switch to a wall-free existence called the L-form state, which could mirror the structure of primordial cells. 

Still image from the video below showing L-form bacteria undergoing cell division [Credit: Cell, Mercier et al]

A study published by Cell Press February 28th in the journal Cell reveals how bacteria in this L-form state divide and proliferate, shedding light on how the earliest forms of cellular life may have replicated.

"The main surprise for me was how simple the mechanism was. It doesn't require any sophisticated protein-based machinery," says senior study author Jeff Errington of Newcastle University. "This makes it plausible as an explanation for how very primitive cells could have proliferated in the very early days of evolution."

The cell wall is a layered structure surrounding cells that protects them and maintains their shape. It is present in all known major bacterial lineages, and it was also probably present in the last common ancestor of bacteria. This structure is so important that it is targeted by antibiotics, and many bacteria responsible for infectious diseases can switch to the L-form state to resist antibiotics.