To understand how sex differences evolve, my project analysed a number of complementary gene expression datasets. These datasets were chosen to encompass different aspects of my overarching aim to understand how sex differences evolve from a shared genome. Datasets included (i) six different bird species that varied in their mating system, (ii) a species of fish where males come in three forms which have different mating tactics, and finally two different fruit fly datasets, (iii) one involving inbred lines and (iv) the other involving chromosome substitutions and genetic crosses. I performed a range of analyses and measured how genetically correlated males and females are in the expression of different types of genes, expression levels of different types of genes, rates of evolution in gene expression and the relationship between gene expression and male behaviour.
Overall, I found that males and females regulate gene expression differently and this largely overcomes the constraint imposed by sharing the same genome. Furthermore, sex chromosomes accentuate sex differences by controlling expression of genes across the whole genome. I also found that high quality in males was controlled by the expression of many genes with small effect, rather than a few key genes with large effect. Together, this research helps to explain how profound differences between males and females can evolve and further adds to our understanding of how males and females can achieve different evolutionary optima.
The datasets produced during this fellowship are publicly available, providing exploitation by future researchers. They include (i) and RNA-seq dataset of ocellated wrasse gonadal gene expression (www.ncbi.nlm.nih.gov/sra) BioProject ID PRJNA344726 (ii) male reproductive phenotypes of a selection of lines from the Drosophila Genetic Reference Panel (
https://doi.org/10.5061/dryad.s3mr73b(odnośnik otworzy się w nowym oknie)) and (iii) the code for transcriptome assembly and data visualisation are available on github (
https://github.com/beckydean(odnośnik otworzy się w nowym oknie)).
This project has resulted in publications in Nature Communications, Molecular Ecology, American Naturalist and Evolution, which have been well cited to date with >100 citations. I have presented at international conferences, including being an invited speaker at a specialist conference organised by the Centre for Ecology and Evolution in London called “War and Peace - the dynamics of evolutionary conflict”. My research has been more widely disseminated through an exhibition at the Grant Museum in London called “Natural Creativity: Sex and Trickery” which I co-organised along with the artist, Clara Lacy. This exhibition highlighted examples of reproductive tactics and deceit in the natural world. The Grant Museum receives over 4000 visitors per month and by showcasing my research on the ocellated wrasse through art, we potentially reached around 8000 members of the public with this outreach activity.
