Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023

The stickleback of Lake Mývatn: detecting microevolutionary change over time using an integrative approach.

Höfundar / Authors: Kasha Strickland (1), Zophonías O. Jónsson (2), Blake Matthews (3), Bjarni K Kristjánsson (4), Joseph Phillips (5), Árni Einarsson (6), Katja Räsänen (7)

Starfsvettvangur / Affiliations: 1. Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK; 2. Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland; 3. Department of Fish Ecology and Evolution, Swiss Federal Institute of Aquatic Science and Technology, EAWAG, Kastanienbaum, Switzerland; 4. Department of Aquaculture and Fish Biology, Hólar University, Iceland; 5. Department of Biology, Creighton University, Omaha, Nebraska, USA; 6. Mývatn Research Station (RAMÝ), Skútustaðir, Iceland; 7. Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland

Kynnir / Presenter: Zophonías Oddur Jónsson

The core aim of evolutionary biology is understanding real-time evolution in wild, often spatially diverse populations. Studying spatio-temporal selection dynamics in real-time is challenging and traditionally research has focused on either spatial differences or change over time. Threespine stickleback (Gasterosteus aculeatus) from lake Mývatn, Iceland, offer a unique system for integrated studies of the dynamics of natural selection. The lakes ecosystem is well characterized, spatially heterogeneous and extremely dynamic, with the stickleback population experiencing variation in selective pressures across both space and time. To explore microevolutionary responses, we measured multiple phenotypic traits for >1000 individuals across 10 sites over a 10 year period (2010 – 2020). We sequenced genomes of 555 fish, to identify regions under selection, comparing allele frequency fluctuations to expectations from genetic drift. By integrating quantitative genetic and genomic tools, we tested to what extent observed trait changes reflect different modes of selection (directional, balancing, and episodic) acting simultaneously on different aspects of the phenotype. Specifically, whilst trophic traits were under directional selection across the 10 year period, swimming related traits were under episodic selection, likely reflecting an extreme population crash. Our study provides a unique empirical demonstration of microevolutionary processes in a wild population.