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Projeto de investigação
Freshwater Bivalves at the edge: Adaptation genomics under climate-change scenarios
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The crown pearl V2: an improved genome assembly of the European freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758)
Publication . Gomes-dos-Santos, André; Lopes-Lima, Manuel; Machado, André M.; Forest, Thomas; Achaz, Guillaume; Teixeira, Amílcar; Prié, Vincent; Castro, L. Filipe C.; Froufe, Elsa
Contiguous assemblies are fundamental to deciphering the composition of extant genomes. In
molluscs, this is considerably challenging owing to the large size of their genomes, heterozygosity,
and widespread repetitive content. Consequently, long-read sequencing technologies are
fundamental for high contiguity and quality. The first genome assembly of Margaritifera
margaritifera (Linnaeus, 1758) (Mollusca: Bivalvia: Unionida), a culturally relevant, widespread,
and highly threatened species of freshwater mussels, was recently generated. However, the
resulting genome is highly fragmented since the assembly relied on short-read approaches. Here,
an improved reference genome assembly was generated using a combination of PacBio CLR long
reads and Illumina paired-end short reads. This genome assembly is 2.4 Gb long, organized into
1,700 scaffolds with a contig N50 length of 3.4 Mbp. The ab initio gene prediction resulted in
48,314 protein-coding genes. Our new assembly is a substantial improvement and an essential
resource for studying this species’ unique biological and evolutionary features, helping promote
its conservation.
Population-specific phenotypic plasticity of endangered bivalves in response to extreme events
Publication . Gomes-dos-Santos, André; Lopes-Lima, Manuel; Silva, Beatriz; Machado, André M.; Pinto, Rui; Österling, Martin; Wallerius, Magnus Lovén; Urbańska, Maria; Golski, Janusz; Runowski, Sławomir; Kaźmierczak, Sandra; Teixeira, Amilcar; Sousa, Ronaldo; Castro, L. Filipe C.; Castro, Paulo; Carvalho, Francisco; Fonseca, Elza; Froufe, Elsa
Freshwater mussels are among the most endangered animal groups, highly sensitive to climate change due to their strict dependence on freshwater habitats. While freshwater mussels are often considered ecologically strict, their distribution across broad environmental gradients raises the possibility of population-specific adaptations mediated by phenotypic plasticity.
This study investigates whether geographically and climatically distinct populations of two freshwater mussel species (Unio pictorum and Unio delphinus) exhibit different transcriptomic responses to prolonged heat stress and whether these responses reveal signs of local adaptation.
We exposed northern and southern populations of both species to gradually increasing temperatures in controlled laboratory conditions, simulating a prolonged thermal extreme event, and RNA-seq was used to quantify differential gene expression.
Results showed strong differences between northern and southern populations of the two species, both in the magnitude and functional composition of transcriptomic responses. Southern populations exhibited intense expression shifts involving classical stress pathways, heat shock proteins, detoxification (cytochrome P450s), apoptosis, and energy metabolism, while northern populations, particularly U. delphinus, showed a markedly subdued response. Notably, U. pictorum's northern population relied heavily on the cytochrome P450 family even at moderate temperatures, while the southern populations of both species activated broader proteostasis and immune responses at higher stress thresholds.
These findings demonstrate clear population-specific phenotypic plasticity, shaped by environmental conditions rather than phylogenetic proximity. They underscore the need for conservation strategies to move beyond species-level management, embracing intraspecific variation as a buffer against climate impacts. As climate change accelerates, safeguarding the evolutionary potential encoded within populations, not just species, is essential to preserving biodiversity resilience.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso para Financiamento de Projetos de Investigação Científica e Desenvolvimento Tecnológico em Todos os Domínios Científicos - 2020
Número da atribuição
PTDC/CTA-AMB/3065/2020