Comparison of whole-genome assemblies of European river lamprey ( Lampetra fluviatilis ) and brook lamprey ( Lampetra planeri )

We present haplotype-resolved whole-genome assemblies from one individual European river lamprey ( Lampetra fluviatilis ) and one individual brook lamprey ( Lampetra planeri ), usually regarded as sister species. The genome assembly of L. fluviatilis consists of pseudo-haplotype one, spanning 1073 Mb and pseudo-haplotype two, spanning 963 Mb. Likewise for the L. planeri specimen, the genome assembly spans 1049 Mb and 960 Mb for pseudo-haplotypes one and two, respectively. Both the L. fluviatilis pseudo-haplotypes have been scaffolded into 82 pseudo-chromosomes, with the same number for the L. planeri pseudo-haplotypes. All four pseudo-haplotype assemblies were annotated, identifying 21,479 and 16,973 genes in pseudo-haplotypes one and two for L. fluviatilis , and 24,961 and 21,668 genes in pseudo-haplotypes one and two for L. planeri . A comparison of the genomes of L. fluviatilis and L. planeri , alongside a separate chromosome level assembly of L. fluviatilis from the UK, indicates that they form a species complex, potentially representing distinct ecotypes. This is further supported by phylogenetic analyses of the three reference Lampetra genomes in addition to sea lamprey ( Petromyzon marinus ).