Molecular Phylogenetics of Freshwater and Marine Sculpins

Molecular phylogenetics has transformed our understanding of the evolutionary history of sculpins (family Cottidae), a diverse group of benthic fishes inhabiting a wide range of freshwater and marine ecosystems across the Northern Hemisphere. By comparing genetic markers such as mitochondrial DNA sequences and fragments of nuclear ribosomal DNA, researchers have reconstructed phylogenetic trees that clarify species boundaries, reveal instances of cryptic diversity and historical introgression, and resolve taxonomic ambiguities at both deep and shallow levels of divergence. Studies employing complete mitochondrial genomes alongside selected nuclear loci have demonstrated that some genera are polyphyletic, prompting taxonomic realignments. Phylogeographic analyses, informed by DNA barcoding and coalescent methods, have identified glacial refugia, post-glacial colonisation routes and ongoing gene flow among closely related lineages. Molecular clocks calibrated with geological events have offered timelines for diversification, often highlighting rapid radiations linked to climatic oscillations and habitat shifts. The integration of molecular data with morphological and ecological traits has underpinned a more coherent taxonomy that reflects evolutionary relationships and informs conservation strategies. Such approaches cast new light on the global significance of sculpin diversity as bioindicators in freshwater systems, as well as their role in marine food webs and fisheries management, by providing an evolutionary framework for species delimitation and monitoring of population structure.

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Molecular Phylogenetics of Freshwater and Marine Sculpins publication trend

The graph below shows the total number of articles in molecular phylogenetics of freshwater and marine sculpins across all publications each year (not limited to Nature Index journals).

Technical terms

Molecular phylogenetics: A field that uses nucleotide sequence data to reconstruct the evolutionary relationships among organisms.

Mitochondrial genome: The circular DNA contained within mitochondria, often used for inferring maternal lineage and phylogenetic relationships.

Nuclear ribosomal DNA (rDNA): Tandemly repeated gene clusters in the nucleus coding for ribosomal RNAs, used as genetic markers for species delimitation and deep phylogenies.

DNA barcoding: The use of a short standardized genetic marker (often COI or cytochrome b) to identify species and assess biodiversity.

References

1. Genetic Evidence for a Mixed Composition of the Genus Myoxocephalus (Cottoidei: Cottidae) Necessitates Generic Realignment. Genes (2020).
2. A new species of the genus Cottus (Scorpaeniformes, Cottidae) from the Baltic Sea Basin and its phylogenetic placement. European Journal of Taxonomy (2022).
3. The characteristics and phylogenetic relationship of two complete mitochondrial genomes of Cottus pollux (scorpaeniformes: cottidae). Mitochondrial DNA Part B (2024).