Biology subjects

Kinnby, A.

Publications and source records attributed to Kinnby, A..

3 recordsLinked to original sources

bioRxiv2022

Adaptive, maladaptive, neutral, or absent plasticity: Hidden caveats of reaction norms

Adaptive phenotypic plasticity may improve the response of individuals when faced with new environmental conditions. Typically, empirical evidence for plasticity is based on phenotypic reaction norms obtained in reciprocal transplant experiments. In such experiments, individuals from their native environment are transplanted into a different environment, and a number of trait values, potentially implicated in individuals response to the new environment, are measured. However, the interpretations of reaction norms may differ depending on the nature of the assessed traits, which may not be known beforehand. For example, for traits that contribute to local adaptation, adaptive plasticity implies non-zero slopes of reaction norms. By contrast, for traits that are correlated to fitness, high tolerance to different environments (possibly due to adaptive plasticity in traits that contribute to adaptation) may, instead, result in flat reaction norms. Here we investigate reaction norms for adaptive versus fitness-correlated traits, and how they may affect the conclusions regarding the contribution of plasticity. To this end, we first simulate range expansion along an environmental gradient where plasticity evolves to different values locally and then perform reciprocal transplant experiments in silico. We show that reaction norms alone cannot inform us whether the assessed trait exhibits locally adaptive, maladaptive, neutral or no plasticity, without any additional knowledge of the traits assessed and species biology. We use the insights from the model to analyse and interpret empirical data from reciprocal transplant experiments involving the marine isopod Idotea balthica sampled from two geographical locations with different salinities, concluding that the low-salinity population likely has reduced adaptive plasticity relative to the high-salinity population. Overall, we conclude that, when interpreting results from reciprocal transplant experiments, it is necessary to consider whether traits assessed are locally adaptive with respect to the environmental variable accounted for in the experiments, or correlated to fitness.

evolutionary biology↗

bioRxiv2022

Clones on the run - the genomics of a recently expanded facultative asexual species

Why, in facultative asexual species, marginal populations are often richer in clones than are core populations, remains unclear. Cloning freezes genotypes but hampers recombination and local adaptation. During expansion, clones are favoured over non-selfing sexuals by uniparental reproduction. To better understand the dynamics of clones and sexual lineage, we used genome-wide sequencing to analyse a recently expanded seaweed. We found large clones and sexual populations mixed close to range margins. Clones had evolved repeatedly from sexual populations but were unexpectedly low in genetic variation. Modelling suggested clones form from sexual populations after repeated bottlenecks at the expansion front. A clonal wave of depauperate genotypes thereafter spread ahead of the sexual population. As we observed, these early formed clones may survive side-by-side sexual individuals, which suggests they lost their sexual capacity. Our study illustrates how range expansion can result in complex and dynamic patterns of genetic variation in facultative asexual species. TeaserWe use genome data and modelling to find out why large clones are only found at range margins in a recently expanded seaweed

evolutionary biology↗

bioRxiv2021

A metagenomic analysis of the wrackbed microbiome indicates a phylogeographic break along the North Sea - Baltic Sea transition zone

Sandy beaches are biogeochemical hotspots that bridge marine and terrestrial ecosystems via the transfer of marine organic matter, such as seaweed (termed wrack). A keystone of this unique ecosystem is the microbial community, which helps to degrade wrack and re-mineralize nutrients. However, little is known about the wrackbed microbiome, its composition, trophic ecology, or how it varies over time and space. Here we characterize the wrackbed microbiome as well as the microbiome of a primary consumer, the seaweed fly Coelopa frigida, and examine how they change along one of the most studied ecological gradients in the world, the transition from the marine North Sea to the brackish Baltic Sea. We found that polysaccharide degraders dominated both the wrackbed and seaweed fly microbiomes but there were still consistent differences between wrackbed and fly samples. Furthermore, we observed a shift in both microbial communities and functionality between the North and Baltic Sea. These shifts were mostly due to changes in the frequency of different groups of known polysaccharide degraders (Proteobacteria and Bacteroidota). We hypothesize that microbes were selected for their abilities to degrade different polysaccharides corresponding to a shift in polysaccharide content in the seaweed communities of the North vs. Baltic Sea. Our results reveal the complexities of both the wracked microbial community, with different groups specialized to different roles, and the cascading trophic consequences of shifts in the near shore algal community.

genomics↗