Evolutionary Quantitative Genetics Workshop

2025 Workshop	SCHEDULE	RESOURCES	PREVIOUS YEARS

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Exercise 2-2: Estimating G-matrices in Drosophila CHCs

Instructor: Jacqueline Sztepanacz

In this activity, we will be analysing data from an experiment in Drosophila serrata conducted by Jacqueline. She set up a paternal half-sibling breeding design to estimate genetic variance in male cuticular hydrocarbon (CHC) pheromone profile, and conducted a binomal fitness assay using these same individuals to get a measure of their mating success. D. serrata has 8 well-studied CHCs that are known to be a target of sexual selection via female choice, and to have an important ecological role in preventing desiccation. We have measured these traits of interest in all offspring from the breeding design, and we also assayed the mating success of these individuals. Our goal is to better understand the genetic basis of these traits and whether they are under selection. In this activity we will analyse a subset of 4 CHC traits in order to estimate the genetic variance and covariance between them (ie. the G matrix), and to estimate direction and non-linear selection acting on these traits.

Script:

• Activity-Code.Rmd
• html output

Data:

• Data.csv
• fullped.csv
• model.Rdata
• model_null.Rdata

Background readings:

• Sztepanacz & Rundle, 2012. Reduced genetic variance among high fitness individuals: Inferring stabilizing selection on male sexual displays in Drosophila serrata