The lack of genetic variation underlying thermal transcriptomic plasticity suggests limited adaptability of the Northern shrimp, Pandalus borealis

Abstract

IntroductionGenetic variation underlies the populations’ potential to adapt to and persist in a changing environment, while phenotypic plasticity can play a key role in buffering the negative impacts of such change at the individual level.MethodsWe investigated the role of genetic variation in the thermal response of the northern shrimp Pandalus borealis, an ectotherm species distributed in the Arctic and North Atlantic Oceans. More specifically, we estimated the proportion transcriptomic responses explained by genetic variance of female shrimp from three origins after 30 days of exposure to three temperature treatments.ResultsWe characterized the P. borealis transcriptome (170,377 transcripts, of which 27.48% were functionally annotated) and then detected a total of 1,607 and 907 differentially expressed transcripts between temperatures and origins, respectively. Shrimp from different origins displayed high but similar level of transcriptomic plasticity in response to elevated temperatures. Differences in transcript expression among origins were not correlated to population genetic differentiation or diversity but to environmental conditions at origin during sampling.DiscussionThe lack of genetic variation explaining thermal plasticity suggests limited adaptability in this species’ response to future environmental changes. These results together with higher mortality observed at the highest temperature indicate that the thermal niche of P. borealis will likely be restricted to higher latitudes in the future. This prediction concurs with current decreases in abundance observed at the southern edge of this species geographical distribution, as it is for other cold-adapted crustaceans.

Spatiotemporal variability in diet composition of Greenland halibut (Reinhardtius hippoglossoides) from the eastern Canadian Arctic

“…In the northwest Atlantic, these changes were seen in the community structure by the mid‐late 2000s, as fish functional groups began to show increases in biomass and crustaceans started to decline (DFO, 2014). Recently, Leung et al (2023) found that P. borealis lacked genetic variation, explaining thermal plasticity. Their results suggest a limited potential of this species for evolutionary thermal plasticity, increasing its vulnerability to future global changes.…”

Diving into broad-scale and high-resolution population genomics to decipher drivers of structure and climatic vulnerability in a marine invertebrate

“…1) experimentally exposed to three temperatures (2, 6, 10°C). Differentially expressed transcripts (DETs) were identified for temperature or regional effects (Leung et al 2023). SNPs associated with transcripts were then identified by mapping the reference transcriptome to the reference genome using Hisat2 (v2.2.1, Kim et al 2015).…”

“…Transcriptomics. The transcriptomic data were originally presented in Leung et al (2023). Briefly, the dataset consists in RNA sequencing data, or transcript counts, from the muscle of 54 adult females from three regions (SS, GSL, NFL; Fig.…”

“…The GOM population is severely depleted (ASMFC 2021), and recent abundance indices in the SS and GSL regions indicate important declines in biomass over the last decade (DFO 2023a(DFO , 2023b. Increased temperature was identified as an important factor affecting the survival of pelagic larval stages and adults of P. borealis in common garden experiments (Ouellet et al 2017;Leung et al 2023;Guscelli et al 2023). It is important to note that genomic offset analyses do not explicitly account for demographic processes such as gene flow and assume an equilibrium in allele-environmental frequencies (Waldvogel et al 2020;Rellstab et al 2021), which may limit their ability to accurately reflect genomic variation in vulnerability to climate change.…”

“…1) was stable over the same period (DFO 2021). Ongoing climate change is expected to further reduce the southern distribution of northern shrimp through significant alterations in habitat, connectivity, and fitness (Le Corre et al 2021; Leung et al 2023). Yet, the impact of genomic and adaptive variation across this range, coupled with changing environmental conditions, on this commercially important species remains unclear.…”