Socially awkward honeybees might provide clues about autism
Bees are intensely social critters. Thousands of them live together in a single hive. They have a clear and strict division of labour, cooperate in complex ways, and their hives hum with intense productivity.
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They are, in many ways, even more social than humans. Which is why when scientists who were studying bees saw some bees not responding to obvious social cues, they knew something interesting was happening. And this led Dr. Gene E. Robinson and his colleagues, after some intense research to study the puzzle, to an answer.
Guest host Torah Kachur talks to Dr. Robinson, the director of the Carl R. Woese Institute of Genomic Biology at the University of Illinois at Urbana Champaign, about the fascinating connection they found with autism spectrum disorder in humans.
This interview has been edited for length and clarity.
Torah Kachur: Now tell me a bit about this unusual behavior that you saw in these bees.
Dr. Gene E. Robinson: Well it started when we were doing observations related to two separate studies. We were studying the response of bees to a social challenge. The challenge involves an unrelated intruder that's placed in a small sort of micro-hive with 10 bees in a plastic petri dish in the laboratory to simulate conditions in the hive. My post doctoral student noticed some bees were not responding to the intruder while others showed the normal response of attacking the intruder.
We when we shifted gears to study social opportunity, which in this case for bees, is an opportunity to rear a larva as a queen - since worker bees don't reproduce themselves, that's the job of the queen, the opportunity to rear a baby sister to let her become a queen is a really big deal a great opportunity - and as soon as bees are presented with a queen larva, they will go to it, feed it, and take care of it. And again some bees did not respond.
TK: How do you make the leap to looking at autism spectrum disorder in humans?
GR: Let me just say, it is a great leap - Autism Spectrum Disorder is a very complex condition. It involves multiple traits - social unresponsiveness is just one of them.
TK: But you still found a connection…
GR: Yes. What we wanted to do was say, 'OK, we see this interesting behavior that has at least an echo in autism spectrum disorder with the social unresponsiveness. What might we do to be able to test this idea a little further?' So we decided to address the issue looking at genes inside the brain of the honeybee.
And the first thing we did was ask do they have distinct patterns of gene activity relative to other bees that are responding to the social challenge or the social opportunity. And indeed, we found that the unresponsive bees show a very distinct pattern with about 1000 genes that are showing differences in activity levels. Now we had a situation where we had genes that were characterizing this unresponsive state and we were ready with that information to turn to the question of, 'Is there any connection between social unresponsiveness in bees and autism spectrum disorder in humans?'
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TK: So what did you find?
GR: We looked at the list of genes that were different in the unresponsive bees, compared it to genes associated with autism spectrum disorder, and asked whether there was any overlap. And in fact there were.
TK: We're talking about two very social species that diverged hundreds of millions of years ago. What happened to the genes in between?
GR: The lineage that has given rise to humans and the lineage that has given rise to honeybees, they parted ways some 600 million years ago. The last common ancestor of these two lineages is thought to have been something like a marine flatworm with a very rudimentary nervous system, no centralized brain yet and moreover no obvious social life.
It's very probable that the social behavior that we see in humans and the social behavior we see in honeybees evolved independently multiple times. And what we get from that is the notion of the 'toolkit,' that there are some genes that form the basic building blocks to elaborate different social systems. And these 'toolkit genes' are used repeatedly and independently in evolution.
TK: Well you made your caveats about comparing humans and bees. And were definitely different, but you think this can still give us any insight into autism spectrum disorder in humans?
GR: Well I think that involves a very careful set of studies where the first thing would be to understand, what do these genes actually do? And then depending on the answers to those questions, ideas could be formulated to cross the huge gap and see what kind of insights we could get.