Honey bees and mammals, including humans, live complex social lives that involve making decisions and interacting with others. For scientists, understanding the genomic bases of these social behaviors for these animals is a largely unanswered question. Advances in sociogenomics – an emerging field that studies the relationship between the genome and social behavior- are beginning to providing scientists with the tools needed to uncover insights that could help answer this question.
Eric Jakobsson, an interdisciplinary computational scientist at the University of Illinois, is one of these scientists who is developing new computational tools to help him and his team of researchers find out if honey bees and mammals share a common genetic origin when it comes to social behaviors.
These tools were able to analyze patterns of gene conservation found in a range of animals. The results of this analysis were published in PLOS Computational Biology and pointed to a surprising find – a set of genes responsible for releasing an alarm pheromone in bees also included a large number of genes that were also found in mammals. To get a better understanding of his study and what this finding means, I interviewed Jakobsson via email.
How did you become interested in studying sociogenomics?
EJ: I became interested in sociogenomics from knowing Gene Robinson and his work. If the field could be said to have one father, he would be a good candidate for that title. But I also became aware that there was skepticism about whether social behavior in his organism of study, honey bees, had any common genomic basis with social behavior in mammals, for example humans. In thinking about this, the idea emerged that perhaps we could use patterns of conservation of genes across species to answer the question, to either confirm or rebut the suspicions of the skeptics. Happily we were able to rebut the skeptics, but we were prepared to report the results whichever way they went.
You indicate in your article that there are a variety of animals that make model organisms for studying the genomic correlates of human social behavior. Why did you choose to conduct your study with honey bees?
EJ: There are powerful scientific reasons for working with honey bees. In some ways honey bee social behavior is different from ours, notably in gender roles. But in some ways it is profoundly similar. An example is the process by which a colony decides on a new site to which to migrate. Scouts go out to prospective sites and return to the colony to describe the location and characteristics of those sites. Different scouts become advocates for their sites and try to recruit others to their side, essentially forming advocacy groups or political parties. Multiple modes of communication are used—visual in the form of dances, chemical in the form of pheromones, and tactile. Eventually one side wins—a convincing majority is won for one site and the colony migrates there. Remarkably, a complex decision is made, because no site is exactly perfect. Rather, both location and dimensions of the site must be balanced. Occasionally the decision making process fails, the colony cannot decide on one direction to go, and the colony divides and dies.
What does your study tell us about conserved genes between honey bees and mammals?
EJ: The study tells us directly and narrowly about genes that in the honey bee are associated with response to a pheromone and are highly conserved in mammals. The study suggests, but does
not prove, that the mammalian orthologs to these genes are also involved in processing conspecific communication. We draw this inference because mammals are social, and conspecific communication is central to sociality, but it is up to future work directly using mammals (perhaps mice) to either confirm or rebut this hypothesis.
One of the aspects of this study was to find out if gene co-expression patterns associated with social behavior were common amongst a wide range of animals. While you were trying to learn more about this, did you find anything that surprised you?
EJ: Two surprises:
- The differentially upregulated genes are involved in remodeling the cell, for example in protein folding and formation of biomolecular complexes. I would have expected shifting between existing pathways, but not constructing the building blocks of pathways. But on reflection, it makes sense, because it provides an additional dimension of complexity for the organism to understand complex patterns of signaling from conspecifics.
- There is a very high degree of orthology across all the metazoan among genes differentially expressed between soldiers reared in their own colonies or reared in opposite colonies (genetically African bees reared in European colonies, and vice versa). Behaviorally the bees adopt the degree of aggression associated with the colony in which they are reared, but their gene expression patterns reflect NEITHER their genetic heritage nor their colony heritage. Rather they reflect whether or not their genetic heritage matched their colony heritage. This is trying to tell us something about nature vs. nurture, but I can’t figure out what.
What will be the next steps for you with this research?
My contributions will continue to be computational, focused on orthology, statistical analysis, etc. More important than my work is the impact on the field that I hope this paper will have. I hope that it will become more widely recognized that the honey bee is a good model organism with relevance to humans, for understanding the foundations of social behavior. I also hope (and would like to work on this myself) that better databases can be constructed to correlate what is known about the relationship of specific genes to behavior in general and social behavior in particular.
Research Article: Liu H, Robinson GE, Jakobsson E (2016) Conservation in Mammals of Genes Associated with Aggression-Related Behavioral Phenotypes in Honey Bees. PLoS Comput Biol 12(6): e1004921.doi:10.1371/journal.pcbi.1004921
Image Credit: Busy Bees by Sharon Sperry Bloom via Flickr