Flies Evolve to Count

Researchers breed fruit flies that, after 40 generations of conditioning, have acquired the ability to react to numbers.

By | July 12, 2012


A team of geneticists have produced the first example of skills gained through directed evolution, by teaching fruit flies to react to a certain number of light flashes. In 20-minute sessions, flies in a container were exposed to flashes of light, with two or four flashes preceding a shake of the container. The experiment was designed to bring out what was assumed to be an innate ability to count in animals. Originally, none of the flies could anticipate the shake, but the 40th generation of shaken flies seemed to have acquired the skill to discern the correct number of flashes associated with a shake during the exercise, and prepare accordingly.

The research team, which presented its findings this week (July 6–10) at the First Joint Congress on Evolutionary Biology in Canada, says the flies can now be used to understand how we process numbers. They suspect numerical skills are rooted deeply in the animal lineage, as many animals have shown some basic capabilities, but delving into the genetic make-up of the wild type and evolved flies could pinpoint the basis for such skills. It could also reveal the genetics of disorders like dyscalculia, which affects people's ability to do basic arithmetic.

“This project was really about getting people interested in using fruit flies as a model system for understanding numerical competence and its evolution,” said study co-author Tristan Long of Wilfrid Laurier University in Waterloo, Canada told Nature. “The obvious next step is to see how [the flies’] neuro-architecture has changed.”

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Avatar of: rosinbio


Posts: 117

July 13, 2012

The assumption that animals in general have an innate counting ability is utterly groundless!

If I understand correctly all those scientists accomplished was to select flies that were better able to distinguish between 2 and 4 light-flashes. Those flies can certainly. see and hear. It is, therefore, quite possible that what was selected for was just a better sense of vision, or hearing, (if the flashes were accompanied by sound produced by the flashing equipment), and not any counting ability which the flies most likely never had. 

Avatar of: James Kohl

James Kohl

Posts: 53

July 13, 2012

The pairing of the light stimulus and shaking seems unlikely to elicit any transgenerational epigenetic effects on neuro-architecture. Operant conditioning (i.e., training) is unlike classical conditioning in this regard. For example, epigenetic effects on intracellular signaling and stochastic gene expression allow Pavlovian conditioning / classical conditioning to directly effect behaviors that help to establish organisms in their ecological niche. That's how nutrient chemicals are responsible for the ecological niche construction that precedes social niche construction and survival of species, which is controlled by the metabolism of nutrient chemicals to the pheromones that control reproduction in species from microbes to man.

The ecological and social niche contribute to the neurogenic niche in invertebrates that allows nutrient chemicals and pheromones to contribute to adaptive evolution by promoting brain changes (e.g., in neuro-architecture) that are passed on to offspring via transgenerational epigenetic inheritance. Vertebrate evolution proceeds along these same lines: ecological, social, neurogenic, but we begin to see some additional epigenetic effects of nutrient chemicals and pheromones because both alter the more highly evolved hypothalamic neurogenic niche that is responsible for vertebrate species survival and the development of our socio-cognitive niche.

Where do others think is the best place to look for changes in neuro-architecture caused by training? Is there a model for that?  

July 15, 2012

Are they really saying that they could make flies to inherit an acquired ability?

That is lamarkism, or the description of the work is really wrong

Avatar of: Roy Niles

Roy Niles

Posts: 32

July 16, 2012

Of course it's what Lamarck was proposing, although he wasn't stressing learning as much as he was stressing experience that makes all creatures learn.  And in any case the theories that organisms create and change their instinctive strategies over time through learning is being demonstrated constantly these days by similar experiments.

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