Lab meeting Nov 25th: Two talks!

Posted by Anna Nordén and Anais Rivas Torres

Next lab meeting Anais and I will give one talk each. Anais will present some of her results from her MSc thesis and I will show some preliminary results and how that is connected to my PhD project. I am going to give the talk at a worm meeting later next week. We would be happy to get any comments on results and tips on how to improve the presentation! Below are two short abstracts summarizing what we will talk about.

Time and place as usual (Tuesday 10:30 in Argumentet, Ecology Building 2^nd floor).

Looking forward to see many of you there!

Anais: Neutrality or coexistence through negative frequency dependence?

Through my research I want to investigate why two related species (Calopteryx splendens and Calopteryx virgo) could coexist, although they have similar niches.

Nowadays, one cannot a priori assume that each and every species found together in a local community need to coexist in the long run. Instead, local community composition might follow a neutral community dynamics. However, ecologically equivalent species cannot coexist infinitely, so there needs to exist some coexistence mechanism(-s) if two or more species are going to continue to coexist locally. The aim of my Master thesis will be to experimentally investigate and search for potential co-existence mechanisms between two ecologically similar damselfly species within the same genus(C. virgo and C. splendens). In particular, I will investigate the possibility of co- existence through negative frequency dependence mechanisms, i.e. that a species does better when it is rare than when it is common.

 Anna: Experimental evolution in Macrostomum lignano

Photo by Micha Eichmann, Schärer Group

Sexual antagonism occurs when the same allele for a gene has opposite fitness effects for females and males. Although generally studied in sexual organisms, sexual antagonism may occur in hermaphrodites and may be one means by which genetic variation is maintained. To investigate this, we measure the response to sex-limited evolution in populations of the flatworm Macrostomum lignano to determine if a hermaphrodite can evolve sex-differentiated chromosomes. A GFP (green fluorescent protein) locus incorporated into the worm’s DNA is used as a dominant sex-determining gene by letting it pass through either eggs (‘female’ treatment) or sperm (‘male’ treatment) in each generation. After many generations, this creates an accumulation of standing genetic variation of sex-specific fitness genes linked to the GFP locus. Additionally, we use quantitative genetics to measure sexually antagonistic genetic variation for fitness in M. lignano. This allows us to look at the heritability of fitness via male and female sex roles, and the amount of genetic diversity that results from our sex-limited evolution experiment. Here, we present preliminary data on the heritability of the GFP marker through male and female sex roles.