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Craig Michell, MSc, doctoral defence 10 Dec: Signatures of host-plant associations in the genomes and larval microbiomes of willow-galling sawflies

The doctoral dissertation in the field of Biology will be examined at the Faculty of Science and Forestry on the Joensuu Campus and streamed live.

What is the topic of your doctoral research?

I use genome sequencing to explore the speciation process of willow-galling sawflies. To understand this process, I looked at three different aspects of the willow-galling sawflies that contribute to speciation (Individual genome level, population level and the microbiome level). These insects are all host specific and by studying several species over the same host plants it is possible to test the repeatability of evolution. How species evolve and the influence of these different aspects on speciation has been a central question in evolutionary studies.

What are the key findings or observations of your doctoral research? 

I assembled the genomes of two different willow-galling sawfly species. These two genomes contribute to the growing number of insect genomes and will be used in future studies exploring evolution in insects. I saw that the evolution of species is not repeatable given the same set of host plants, but is rather influenced by many different events. In the microbiome study, I saw a high diversity of bacteria associated with these insects. Based on the potential functions that the bacteria may provide to the insect, it is possible that they contribute to the ecology of these insects.

What are the key research methods and materials used in your doctoral research? 

I used a combination of sequencing technologies to answer these questions. I used high-coverage genome sequencing and Nanopore sequencing to assemble the genomes of two sawfly species. I then used whole genome resequencing to explore different sawfly species and confirm the host specificity of these species. Finally, I used bacteria 16S metabarcoding to understand the bacterial community and how it changes based on host plant and gall type.

The doctoral dissertation of Craig Michell, MSc, entitled Signatures of host-plant associations in the genomes and larval microbiomes of willow-galling sawflies, will be examined at the Faculty of Science and Forestry on the Joensuu Campus, Natura, N100, and online, on 10 December at 2 pm. The opponent will be Professor Craig Primmer, University of Helsinki, and the custos will be Senior Researcher, Jaakko Pohjoismäki, University of Eastern Finland. Language of the public defence is English.

For further information, please contact:

Craig Michell, craig.michell (a) uef.fi

Public examination (to be updated)

Dissertation book online 

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