Lampreys are the focus of intense research. Together with hagfishes, they form the Cyclostomata, the sister group of jawed vertebrates, and hence they are a key group for disentangling the early evolution of many vertebrate features (Shimel and Donoghue 2012; McCauley et al. 2015). Ecologically, lamprey species show a diverse array of life modes, including parasitic and non-feeding species, and inhabit freshwater and marine habitats or both (i.e. anadromous species; Docker and Potter 2019). One of these anadromous species, the sea lamprey (Petromyzon marinus), took advantage of man-made canals to invade the North American Great Lakes in the early 20th century, decimating many fish populations. Today, the control of these invasive populations is paramount for the survival of the region’s fishing industry (Ferreira-Martins et al. 2021). All these research avenues will benefit from the generation of new genomic data, an invaluable resource in evolutionary and conservation biology.

In this manuscript, Tørresen‬ et al. (2025) present phased, chromosome-level assemblies from two lamprey species: the European river lamprey (Lampetra fluviatilis) and the brook lamprey (Lampetra planeri). These two genome assemblies are of high quality and will undoubtedly become a key resource in lamprey research. In particular, the authors showcase the potential of such genomes from two perspectives. First, comparing their assemblies to the already published genomes from P. marinus and another specimen of L. fluviatilis, they propose that lamprey genomes are highly conserved and display large syntenic blocks shared among species. Second, phylogenetic analyses and the annotation of SNPs suggest that L. fluviatilis and L. planeri should be considered two ecotypes of the same species complex, instead of two separate species. This might not be new for anyone knowledgeable in lamprey biology (Rougemont et al. 2017), but it is surprising given the distinct ecology of the two lampreys: L. fluviatilis is a parasitic, anadromous species, whereas L. planeri is a non-feeding, freshwater species. 

In addition to the biological significance of this manuscript, I would like to acknowledge the robustness of the analytical approaches. These genomes were assembled and annotated following two pipelines recently developed at EBP-Nor, the Norwegian initiative of the Earth BioGenome Project (EBP). These pipelines are designed to be an easy-to-use, end-to-end solution for genomic analyses and are likely to become a standard for the EBP and European Reference Genome Atlas initiatives. There can be no better evidence of their effectiveness than these two phased, chromosome-level, highly complete genome assemblies.

References

Docker MF, Potter IC (2019) Life history evolution in lampreys: Alternative migratory and feeding types. In: Docker M (ed) Lampreys: Biology, Conservation and Control. Fish & Fisheries Series, vol 38. Springer, Dordrecht. https://doi.org/10.1007/978-94-024-1684-8_4

Ferreira-Martins D, Champer J, McCauley DW, Zhang Z, Docker MF (2021) Genetic control of invasive sea lamprey in the Great Lakes. Journal of Great Lakes Research, 47, S764-S775. https://doi.org/10.1016/j.jglr.2021.10.018

McCauley DW, Docker MF, Whyard S, Li W (2015) Lampreys as diverse model organisms in the genomics era. BioScience, 65(11), 1046-1056. https://doi.org/10.1093/biosci/biv139

Rougemont Q, Gagnaire PA, Perrier C, Genthon C, Besnard AL, Launey S, Evanno G (2017) Inferring the demographic history underlying parallel genomic divergence among pairs of parasitic and nonparasitic lamprey ecotypes. Molecular Ecology, 26(1), 142-162. https://doi.org/10.1111/mec.13664

Shimeld SM, Donoghue PC (2012) Evolutionary crossroads in developmental biology: cyclostomes (lamprey and hagfish). Development, 139(12), 2091-2099. https://doi.org/10.1242/dev.074716

Tørresen OK, Garmann-Aarhus B, Hoff SNK, Jentoft S, Svensson M, Schartum E, Tooming-Klunderud A, Skage M, Krabberød‬​ A, ‭Vøllestad‬​ LA, Jakobsen KS (2025) Comparison of whole-genome assemblies of European river lamprey (Lampetra fluviatilis) and brook lamprey (Lampetra planeri). bioRxiv, ver. 5 peer-reviewed and recommended by PCI Genomics https://doi.org/10.1101/2024.12.06.627158​