This project aims to explore the underlying mechanism behind inducible morphological defences in a common freshwater living fish species, namely the crucian carp (Carassius carassius). This species shows an extreme morphological plasticity towards the prevailing risk of predation by e.g. the capacity to induce a deeper body shape when under high risk of predation – a trait that directly reduces the risk of mortality from gape-size limited predator e.g. the norhern pike (Esox lucius). To do this, we conducted a laboratory experiment where crucian carps were reared with or without pike during a total time of six months. In the end of the experimental period, organs (brain, kidney and muscle) were collected and prepared for RNA-seq. The purpose is to compare gene expression between fish dependent on differences in the experimentally induced predation risk. Selected features representing specific biological processes and include genes associated with the stress-axis (HPI-axis), endocrine system regulation, energy metabolism, development/growth regulation and muscular function. In addition, genes associated with olfaction and vision are of interest and expected to be up-regulated in fish that coexisted with pike. Finally, since we have included both males and females at equal proportions in our sampling, we will have a possibility to look for sexual differences in general as well as in the above mentioned situations in particular.
We recently got a lot of RNAseq data, 2.4 B read pairs, i.e. 720 Gbp of data, and this will now be analysed on Uppmax.