Development of tools to rapidly identify cryptic species and characterize their genetic diversity in different European kelp species

Abstract

Marine ecosystems formed by kelp forests are severely threatened by global change and local coastline disturbances in many regions. In order to take appropriate conservation, mitigation and restoration actions, it is crucial to identify the most diverse populations which could serve as a "reservoir" of genetic diversity. This requires the development of specific tools, such as microsatellite markers to investigate the level and spatial distribution of genetic diversity. Here, we tested new polymorphic microsatellite loci from the genome of the kelp, Laminaria digitata, and tested them for cross-amplification and polymorphism in four closely related congeneric species (Laminaria hyperborea, Laminaria ochroleuca, Laminaria rodriguezii and Laminaria pallida). Adding these 20 new microsatellite loci to the ten L. digitata loci previously developed by Billot et al. (1998) and Brenan et al. (2014) and to the ten L. ochroleuca loci previously developed by Coelho et al. (2014), we retained a total of 30 polymorphic loci for L. digitata, 21 for L. hyperborea, 16 for L ochroleuca, 18 for L. rodriguezii and 12 for L.pallida. These markers have been tested for the first time in the last two species. As predicted, the proportion of markers that cross-amplified between species decreased with increasing genetic distance. In addition, as problems of species identification were reported in this family, mainly between L. digitata and Hedophyllum nigripes, but also between L. digitata, L. hyperborea and L. ochroleuca in areas where their range distributions overlap, we report a rapid PCR identification method based on species-specific COI mitochondrial primers that allows these four species of kelp to be rapidly distinguished.

Influence of oceanography and geographic distance on genetic structure: how varying the sampled domain influences conclusions inLaminaria digitata

“…Prior analyses The PCA run on the whole dataset allowed to identify 12 L. hyperborea individuals (Figure S1, Table S1), a sister species to L. digitata with an overlapping range distribution (Robuchon et al 2014). Their identities were additionally confirmed based on allelic size at markers Ld148, Ld158, Ld704, Lo4-24 and Lo454-23 following Mauger et al (2021). These individuals were sampled in populations S6 (2 ind.…”