GoKawiilUnderstanding the origin of life requires addressing a collection of overlapping scientific questions. We’ve made a lot of progress toward explaining how simple chemicals present on an early Earth built the complex molecules used by life and how some of those chemicals built the first genetic/catalytic molecules. But we’re much further from understanding a key conundrum: How did membranes end up surrounding the first cells?
It’s relatively easy to make membranes spontaneously form in water, and they’ll enclose anything dissolved in that water, including nucleic acids. But the membranes then cut their interior off from everything else in the solution. Any interesting chemical reactions enclosed there would eat through the raw materials and grind to a halt.
Now, a lab at the University of Minnesota has announced that it has developed a simplified system in which a membrane encloses some genetic material but can continually import new materials supplied to it. The system also spontaneously divides, producing a few generations of “offspring” before things start failing. It’s still extremely dependent upon human intervention, but it might provide a new avenue to explore questions about the origin of life and what a truly minimalistic form of life might look like.
The genetics of SpudCells
The work was done by a team led by Kate Adamala, and it hasn’t yet undergone peer review (a draft manuscript has been posted online). It mostly involved putting together pieces of biological systems described or developed by other researchers and wrapping them in a membrane. Many of these pieces originated in viruses, which are often notable for having stripped-down versions of systems that are far more elaborate in cells.
For example, the system used to copy the DNA of what Adamala is calling a “SpudCell” is derived from a virus that infects bacteria called Phi29. A different research group had already demonstrated that DNA encoding the proteins this virus uses to copy its DNA can be placed inside a membrane, where it would replicate its own DNA. So the researchers adapted this to their own system, which spreads roughly 90,000 bases of DNA across seven separate circular DNA molecules.