Research in the laboratory investigates the evolution and development of morphology. We’re particularly interested in the interplay of nature and nurture in affecting final adult morphology. We use a variety of approaches including genetics, genomics, and developmental biology.
Our study system is the pea aphid. Aphids are remarkable insects, able to produce a variety of morphologies across their complex life cycles that alternate between asexual and sexual development. During the asexual phase, females are often wingless and specialize in the mass production of genetically identical wingless daughters. However, if their host plant becomes too crowded, those same females can switch to producing daughter that have wings as adults so that those daughters can fly away and find better food sources. Thus, winged and wingless females of pea aphids are genetically identical yet morphologically very different. How these alternative morphologies are produced is one of the main questions we address in the lab.
During their sexual phase in the fall, pea aphids produce winged and wingless males as well. However, unlike the females the males are not genetically identical and their morphology is not determined by environmental circumstances. Rather, adult male morphology appears to be under the control of a single locus on the X chromosome called aphicarus.
Ongoing projects in the lab include:
• Understanding the male wing dimorphism system. Males are winged and wingless in some species, but monomorphic in others. How has this trait evolved across aphid species? What is the genetic basis of wing dimorphism and is that mechanism the same or different across species?
• Discovering the molecular mechanisms underlying developmental plasticity in pea aphid asexual females. How does a pea aphid mother sense her environment and pass that information on to her developing embryos? How does the developmental timing of environmental sensitivity differ among aphid species?
• Investigating genetic variation for the female polyphenism. We’ve observed that aphid lines respond to high density environments differently. How extensive is this variation in nature? What genes underlie this plasticity variation?
- Vellichirammal, N. N., Gupta, P., Hall, P., and J. A. Brisson. 2017. Ecdysone signaling underlies the pea aphid transgenerational wing polyphenism. Proc. Nat. Acad. Sciences. doi:10.1073/pnas.1617640114.
- Grantham, M. E., Antonio, C. J., O’Neil, B. R., Zhan, Y. X., and J. A. Brisson. 2016. A case for a joint strategy of diversified bet hedging and plasticity in the pea aphid wing polyphenism. Biol. Letters 12:20160654.
- Vellichirammal, N. N., Madayiputhiya, N., and J. A. Brisson. 2016. The genome-wide transcriptional response underlying the pea aphid wing polyphenism. Mol. Ecol. 25:4146-4160.
- Brisson, J. A., and G. K. Davis. 2016. The right tools for the job: Regulating polyphenic morph development in insects. Curr. Op. Insect Science 13:1-6.
- Zera, A. J., and J. A. Brisson. 2015. Evolutionary and ecological physiology of polyphenism: Integrating proximate and ultimate mechanisms. In: Integrative Organismal Biology. Eds: Martin, L. B., Ghalambor, C. K., and A. Woods. Oxford University Press.
- Purandare, S., Bickel, R. D., Jaquiery, J., Rispe, C., and J. A. Brisson. 2014. Accelerated evolution of morph-biased genes in pea aphids. Mol. Biol. Evol. 31: 2073-2083.
- Bickel, R. D., Dunham, J. P., and J. A. Brisson. 2013. Widespread selection across coding and noncoding DNA in the pea aphid genome. G3: GENES, GENOMES, GENETICS. 3: 993-1001.