Biology subjects

Kvarnemo, C.

Publications and source records attributed to Kvarnemo, C..

2 recordsLinked to original sources

bioRxiv2026

Convergent molecular changes in populations of two pipefish species in the Baltic Sea

While studies of molecular convergence typically focus on species that independently evolved similar phenotypes, similar questions can be asked among populations of different species adapting to the same environment. Here, we study the Baltic Sea environmental gradient and two co-distributed, ecologically similar, but distantly related pipefish species, the broadnosed pipefish (Syngnathus typhle) and the straightnose pipefish (Nerophis ophidion), to test whether independent colonization of the Baltic Sea led to similar population structure and caused convergence at different genomic levels. Using a new diploid genome for S. typhle and whole-genome resequencing data (N=99 for S. typhle; N=81 for N. ophidion) across seven locations from France to Finland, we identified stronger population structure in S. typhle than in N. ophidion, while both species showed differentiation between North Atlantic, Danish Straits, and Baltic Sea populations. Genetic diversity was lower in Baltic populations, particularly in S. typhle. Cross-species comparisons of Baltic populations revealed contrasting chromosome-level patterns of genomic differentiation, with differentiation spread across the genome in S. typhle but concentrated in specific chromosomal regions in N. ophidion. Nonetheless, we identified multiple orthologous genes and SNPs showing convergent differentiation in the Baltic populations of both species, including genes related to metabolism, immunity, and regulatory functions. Overall, we identified molecular convergence at the gene and nucleotide level between Baltic populations of distantly related pipefish species, while convergence was limited at broader genomic scales. These findings suggest that similar environmental pressures can repeatedly target specific genetic elements even when genomic backgrounds and population structures differ.

evolutionary biology↗

bioRxiv2024

Sexual display behavior follows consistent sex-specific reaction norms across latitude in response to operational sex-ratio.

Predicting the strength and direction of sexual selection is a challenging task for evolutionary theory, as the effects of ecological factors, social environment, and behavioural plasticity, all need to be taken into account. The Operational Sex Ratio (OSR) is a key variable, which has been shown to (i) affect the strength and direction of mating competition, as a social environment cue, and (ii) be affected itself by ecological conditions through sex-specific environmental effects. Yet, gaining a global view of (i) and (ii) in wild populations represents an arduous but necessary step to further our understanding of sexual selection dynamics in the wild. Here, we address this challenge by using reaction norms. We conducted an extensive field study on the two-spotted goby Pomatoschistus flavescens, monitoring six populations along a latitudinal gradient during an entire breeding season. Doing so, we compared across populations the temporal trajectories in social environment and sexual displays, which is unprecedented. We develop a reaction norm framework based on OSR theory to analyse the data. We show that what appears to be tremendous variation in sexual displays across populations and sampling times, follows consistent rules: sexual display behaviour follows behavioural reaction norms in response to the social environment that are consistent across populations, but social environment fluctuations are specific to each population. Recording behaviour not only over time, but also along a latitudinal gradient where ecological conditions change and in turn affect OSR, was necessary to gain insight into the relationship between social environment and sexual displays, which in turn contributes to sexual selection dynamics.

evolutionary biology↗