The first self-replicating 'robots' made from living cells have been engineered by scientists.
The resemblance to the video game character is probably the least strange thing about the 'xenobots.'
The world's first robot constructed entirely out of living cells was presented last year, and these strange robotic creatures are a spin-off.
Joshua Bongard, a computer scientist and roboticist from the University of Vermont, said at the time that these are novel living machines.
They are not a traditional robot or a known species of animal. It's a new class of artifact, a living, programmed organisms.
Bongard and his team have given the xenobots the ability to self-replicate and create new versions of themselves.
The self-replication isn't achieved by the kind of reproduction techniques we normally see in biological life-forms.
The researchers found that if they put enough of the xenobots in close proximity with one another in a petri dish, their collective movement began to pile up other loose frog cells floating alongside in the solution.
The aggregated heap of about 50 cells became a kind of offspring to the xenobot organism, capable of swimming by itself, and in so doing, piling up its own offspring.
The phenomenon, called sequestration self-replication, has been seen in other machines and models, but never before in living multicellular systems.
The researchers explain in a new paper that synthetic multicellular assembly can replicate by moving and compressing cells in their environment into functional self-copies.
"This form of perpetuation, previously unseen in any organisms, arises spontaneously over days rather than evolving over thousands of years."
Sam Kriegman and Douglas Blackiston are related.
Simulation predicts the self-replication system.
To make the self-replicating robot, the researchers took the stem cells from the African clawed frog embryo skins and put them in a solution of salt and water for a period of time.
When a dozen of the first- generation organisms were dropped into a second dish along with stem cells, the movement of the organisms clumped the stem cells into piles that formed a new generation of organisms.
The stem cells that were left alone in solution did not self-assemble, showing they needed the initial movement of the progenitor xenobots to initiate their formation into aggregated organisms.
The researchers explained in their paper that the behavior of the self-replication in plants and animals is a demonstration of how biological entities can adapt and change in response to their environment.
The team found that they could amplify the phenomenon by using artificial intelligence.
Some body shapes amplified pile size and replication rounds, while others damped or halted self-replication, according to simulations. Some geometries were better than the spheroids.
The semitorus shape was the best choice for piling loose frog cells into new organisms, as well as introducing walls that restrict the movement of the xenobots, because of its resemblance to the film "Pac-Man in 3D".
While we're still very much at the beginning of messing with these living robot creatures, the researchers say the unusual organisms could one day perform useful work, if we can keep figuring out how they function, and also decide the right jobs to give them.
"This suggests that future technologies with little outside guidance may become more useful as they spread, and that life harbors surprising behaviors just below the surface, waiting to be uncovered," the team explains.
The findings are reported in a journal.
