Scientists in America have discovered a way of completely reprogramming the brains of ants by tweaking the activity of their genes.
The findings, discovered by Professor Shelley Berger at the University of Pennsylvania, suggest that there is a chance that human behavior can be manipulated in a similar way.
In order to reprogram the ants, a team of scientists zeroed in on the ‘epigenetic’ controls, which switch genes on and off without permanent changes their DNA.
They found that manipulating this layer of genetic control made it possible to reprogram the ants to change their foraging behaviour.
Carpenter ant colonies are made up of two types of worker.
Major workers are large brawny ants with large heads and powerful mandibles, for moving larger food items and defending the colony against attack.
Previous studies by the group showed that epigenetic controls were responsible for determining whether an ant was a major or minor worker.
In other words, the same genes were switched on in both types of ant, but an additional level of control decided how they develop into major or minor workers.
A previous study revealed that in the minor workers, the genes involved in brain development were much more active.
In order to keep things neat and protected, the DNA inside cells is tightly packaged.
The DNA strand is coiled around ball-like proteins called histones – like twisting a telephone cord around your finger – which in turn are packed tightly together into larger protein complexes.
But adding a chemical group called acetyl to the histones – a process called acetylation – makes them space out, exposing the DNA strand and allowing genes to be easily read and transcribed.
By adding and removing these chemical ‘Post-it notes’ to histones, the body can regulate how genes are expressed, effectively dialling the activity of the genes up or down.
The researchers found that this type of epigenetic modification could be used to change the ants’ behaviour.
‘The results suggest behavioural malleability in ants, and likely other animals, may be regulated in an epigenetic manner via histone modification,’ said Dr Daniel Simola, a biologist at Pennsylvania and co-lead author of the study.
When the team fed minor workers with a drug which inhibited the removal of the acetyl groups from histones, for example, the ants foraged and scouted for food more.
But when they were fed a drug which blocked acetylation – so acetyl groups couldn’t be added – they foraged much less.
For the larger workers, the inhibitor drug caused no change in foraging activity.
However, when they injected the inhibitors into the brains of immature major workers, the foraging activity was boosted to similar levels as the minor ants.
They found that just a single treatment with the inhibitor drug was enough to induce and sustain minor-like foraging in the majors for up to 50 days.
The findings suggest there is a critical developmental window, an ‘epigenetic window of vulnerability’, in the brains of young ants, which makes them more susceptible to environmental factors.
A crucial factor is the ant study was found to be an enzyme called CBP, which adds acetyl groups to histones.
This enzyme has previously been implicated in learning and memory in mice and is mutated in certain cognitive conditions in humans.
Professor Berger added: ‘From mammalian studies, it’s clear this is an important protein involved in learning and memory.
‘The finding that CBP plays a key role in establishing distinct social behaviours in ants strongly suggests that the discoveries made in ants may have broad implications for understanding social organization.’
The research is published in Science.