Queen or worker? Flexibility between roles relies on just a few genes

October 19, 2015, Biotechnology and Biological Sciences Research Council
The dinosaur ant, Dinoponera quadriceps. Credit: Chris Tranter

Two insect species from Latin America, the dinosaur ant and the red paper wasp, have been used to uncover the molecular mechanisms underpinning queen and worker roles in social insects. The research by an international team of scientists brings us closer to understanding how genomes are used to generate castes in social evolution.

Researchers from the University of Bristol, the Babraham Institute (Cambridge, UK) and the Centre for Genomic Regulation (Barcelona, Spain) analysed individual wasp and ant brains from queens and workers of both species to see whether caste differences could be explained by variations in how the genome is 'read' and regulated.

As published in the latest issue of PNAS, the two species revealed much more than honeybees about how queen and worker castes evolve in insect societies. Dr Seirian Sumner, a senior author on the paper, and a senior lecturer at the University of Bristol, explains: "Unlike honeybees, who as larvae are fated irreversibly to be a queen or worker, paper wasps and dinosaur ants are able to switch role from worker to queen at any point in their life. This flexibility is thought to represent the first stages of caste evolution, when the simplest societies form."

Queens and workers of and dinosaur ants look identical. It was only by observing the insects' behaviours and social interactions that the researchers were able to identify their roles. To do this, the researchers fitted the insects with tiny paint spots or identification tags to study the insects in their natural environments.

A paper wasp with painted identification marks. Credit: Solenn Patalano

Comparing the molecular differences between queens and workers of both species was surprising. "We found very few differences in and gene functional specialisation between queens and workers in both the ant and the wasp," said Dr Solenn Patalano from the Epigenetics Programme at the Babraham Institute and lead author on the paper. "In both, less than one per cent of the genome showed noticeable differences in expression levels. This was unexpected as many hundreds of genes are involved in differentiating queens and workers in the honeybee."

Instead, the authors found that castes were differentiated by subtle, but non-random arrangements of gene networks. "This suggest that there is no single master gene regulating caste differentiation in these simple societies, and that genes for simple social behaviour act in interconnected networks involving many genes of small effect," explained Dr Sumner.

The authors also looked at whether epigenetic modifications to DNA (DNA methylation) might be regulating these subtle gene networks. "Surprisingly, we found no evidence that queen- and worker-specific gene expression was driven by DNA methylation and more generally the ant and wasp genomes lack strong epigenetic signatures." said Dr Patalano. "We suggest that this absence of molecular commitment keeps the genome open and responsive, facilitating the behavioural plasticity we see in these species."

Credit: Biotechnology and Biological Sciences Research Council

"As part of this research we are also really excited to be publishing the first genome sequence for a social wasp!" Dr Sumner added. "Genome sequences exist for eleven ant species and three bee species. The sequencing of the first wasp genome completes the trio of the social Hymenoptera (bees, wasps and ants), giving us a more balanced understanding of the molecular basis of sociality in insects, and opens up exciting new avenues of research into a somewhat neglected group of insects."

Professor Wolf Reik, Head of the Epigenetics Programme at the Babraham Institute, associated faculty at the Wellcome Trust Sanger Institute and a senior author on the paper, said: "We are excited about discovering which in these wasps and ants allow easy switching between workers and queens. There are some applications of these principles to human stem cells to make them more plastic, potentially leading to better stem cell therapies in the future."

"The work illustrates the relevance of genomic approaches, including genome and transcriptome sequencing, to understand animal behaviour. They help to uncover the genetic basis underlying behavioural traits." added Professor Roderic Guigó, coordinator of the Bioinformatics and Genomics Programme at the Centre for Genomic Regulation in Barcelona, Spain.

Explore further: Wasp transcriptome creates a buzz

More information: Molecular signatures of plastic phenotypes in two eusocial insect species with simple societies, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1515937112

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11 comments

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JVK
1 / 5 (2) Oct 21, 2015
...revealed much more than honeybees about how queen and worker castes evolve in insect societies.


...this absence of molecular commitment keeps the genome open and responsive, facilitating the behavioural plasticity we see in these species."


The presence of molecular commitment is all organized genomes is nutrient-dependent and in species from microbes to humans the molecular commitment is pheromone-controlled via the physiology of reproduction. Cell type commitment does not automagically evolve in any society.

The honeybee model organism is the best example of what happens due to a single nutrient-dependent RNA-mediated amino acid substitution that differentiates the cell types of queens and workers and also differentiates their behaviors. See for other examples:

Nutrient-dependent/pheromone-controlled adaptive evolution: a model.http://www.ncbi.n...24693353

Vietvet
5 / 5 (2) Oct 21, 2015
Nutrient-dependent/pheromone-controlled adaptive evolution: a model.http://www.ncbi.n...24693353

Criticisms of the nutrient-dependent pheromone-controlled evolutionary model
http://www.ncbi.n...4049134/

"Kohl also shows significant comprehension issues within his own paper and in external discussions of references he believes support his model."

JVK's" significant comprehension issues" are on display with his every comment.

anonymous_9001
5 / 5 (2) Oct 21, 2015
The honeybee model organism is the best example of what happens due to a single nutrient-dependent RNA-mediated amino acid substitution that differentiates the cell types of queens and workers and also differentiates their behaviors.


Would you agree that epigenetic differentiation that dictates whether a larva becomes a queen or a worker does not make changes to the DNA sequence but merely modulates expression of various genes?
JVK
1 / 5 (2) Oct 21, 2015
Why would I agree to anything that is claimed by an anonymous fool (aka Andrew Jones) who claimed "...James Kohl presents an unsupported challenge to modern evolutionary theory and misrepresentations of established scientific terms and others' research,"

You know perfectly well what I have claimed. It refutes every aspect of the Modern Synthesis, and your face-saving attempts can either be placed into the context of a model of biologically-based cause and effect for comparison to mine, or you can continue to be the fool you always have been.

I wrote: "Cell type commitment does not automagically evolve in any society."

See: "Structural diversity of supercoiled DNA" http://dx.doi.org...omms9440

This group is also claiming that everyone like you is a biologically uninformed science idiot.
See: https://www.youtu...youtu.be All About that Base (Meghan Trainor Parody)

Would you agree with their claim that Tyson is a big ass?
anonymous_9001
5 / 5 (2) Oct 21, 2015
So you would disagree that epigentically-based differentiation doesn't make changes to DNA sequence. That's too bad, because you would be wrong. Here's a paper that describes how that process occurs:

http://www.insect...61.shtml

Do you have evidence that a larva's DNA sequence changes when it differentiates into a worker/queen?
JVK
1 / 5 (2) Oct 21, 2015
I wrote: "Cell type commitment does not automagically evolve in any society."

Your face-saving attempts exemplify the desperate acts of a biologically uninformed science idiot with no idea of how cell type differentiation occurs.

Stop trying to put words in my mouth.

Here's the paper that linked our 1996 model of hormone-organized and hormone-activated behavior from yeasts to mammals to their insect model. Organizational and activational effects of hormones on insect behavior http://www.ncbi.n...10980296 before they moved forward to link the RNA-mediated life history transitions to the honeybee model organism in Honey bees as a model for understanding mechanisms of life history transitions http://www.ncbi.n...15925525
anonymous_9001
5 / 5 (2) Oct 22, 2015
Since you can't post anything but personal attacks, my question stands:

Do you have evidence that a larva's DNA sequence changes when it differentiates into a worker/queen?

Neither alterations or splicing are responsible for amino acid substitutions, which are the result of changes in codons because neither make changes to DNA.
JVK
1 / 5 (2) Oct 22, 2015
Please take one minute to review the editor's response to "Criticisms of the nutrient-dependent pheromone-controlled evolutionary model." http://www.ncbi.n...4049134/

"The 2013 review article by James Vaughn Kohl published in Socioaffective Neuroscience & Psychology and criticized in the above Letter to the Editor was subjected to standard peer review and the revised version was accepted by me after it had been accepted by both reviewers."

Like me, he claims you are a biologically uninformed science idiot. Arguably, he was too polite, and you did not realize that he was also calling you a "big ass" like the serious scientists did to Neil deGrasse Tyson in their musical parody.

Please also take this opportunity to play the musical parody while looking in the mirror. Watch the words in-between your glances at the mirror and try to determine who they are directing their comments to.
anonymous_9001
5 / 5 (2) Oct 22, 2015
Like me, he claims you are a biologically uninformed science idiot. Arguably, he was too polite


What's especially hilarious in this situation is that 11 hours before posting that, you wrote this:

Stop trying to put words in my mouth.


Stop putting words in Mouras' mouth. You literally just did what you told me not to do. Again, I refer you to the term "hypocrite."
Captain Stumpy
5 / 5 (1) Oct 22, 2015
Please take one minute to review the editor's response to "Criticisms of the nutrient-dependent pheromone-controlled evolutionary model." http://www.ncbi.n...4049134/
@When i queried the magazine senior editors and staff, this is the reply i got
hello harold,
So say it's hot paper kohl sent ... you will have to remove it, or you pubie every forum against: it is also a way to dismantle the pseudo science. j bises
caroel
translated from French: original from the magazine
salut harold,
dis donc c'est chaud le papier de kohl….soit tu va devoir le retirer, soit tu pubie toutes les tribunes contre : c'est aussi une facon de démonter la pseudo science. j bises
caroel
so, again, you put words into people's mouths and get caught lying, posting pseudoscience and creationist dogma, & that is why you have no credibility
Captain Stumpy
5 / 5 (1) Oct 22, 2015
@jk "i like big butts" trolling above
so as you can see... when i queried the magazine, the feedback pretty much stated you were ... in your own words
a "big ass"
so continuing to put words into the mouths of people while not comprehending the science and ignoring the evidence just makes you look stupid.

in your own words
Please also take this opportunity to play the musical parody while looking in the mirror.
the ONLY reason you are still here posting on PO is that you are being protected

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