Genetic population structure of the pelagic mollusk Limacina helicina in the Kara Sea

Abstract

BackgroundPelagic pteropods Limacina helicina are widespread and can play an important role in the food webs and in biosedimentation in Arctic and Subarctic ecosystems. Previous publications have shown differences in the genetic structure of populations of L. helicina from populations found in the Pacific Ocean and Svalbard area. Currently, there are no data on the genetic structure of L. helicina populations in the seas of the Siberian Arctic. We assessed the genetic structure of L. helicina from the Kara Sea populations and compared them with samples from around Svalbard and the North Pacific.MethodsWe examined genetic differences in L. helicina from three different locations in the Kara Sea via analysis of a fragment of the mitochondrial gene COI. We also compared a subset of samples with L. helicina from previous studies to find connections between populations from the Atlantic and Pacific Oceans.Results65 individual L. helinica from the Kara Sea were sequenced to produce 19 different haplotypes. This is comparable with numbers of haplotypes found in Svalbard and Pacific samples (24 and 25, respectively). Haplotypes from different locations sampled around the Arctic and Subarctic were combined into two different groups: H1 and H2. The H2 includes sequences from the Kara Sea and Svalbard, was present only in the Atlantic sector of the Arctic. The other genetic group, H1, is widespread and found throughout all L. helicina populations. ϕ ST analyses also indicated significant genetic difference between the Atlantic and Pacific regions, but no differences between Svalbard and the Kara Sea.DiscussionThe obtained results support our hypothesis about genetic similarity of L. helicina populations from the Kara Sea and Svalbard: the majority of haplotypes belongs to the haplotype group H2, with the H1 group representing a minority of the haplotypes present. In contrast, in the Canadian Arctic and the Pacific Ocean only haplogroup H1 is found. The negative values of Fu’s Fs indicate directed selection or expansion of the population. The reason for this pattern could be an isolation of the Limacina helicina population during the Pleistocene glaciation and a subsequent rapid expansion of this species after the last glacial maximum.

Pathways of Pelagic Connectivity: Eukrohnia hamata (Chaetognatha) in the Arctic Ocean

“…Questel et al (2016) found no evidence of population structure based on mtCOI for copepod species of Pseudocalanus, and recent studies using mitochondrial and microsatellite makers concluded that Arctic populations of the copepod C. glacialis are panmictic (Weydmann et al, 2016(Weydmann et al, , 2018, but see Nelson et al (2009). Patterns of COI haplotype diversity also supported Pan-Arctic dispersal of the pteropod Limacina helicina, with evidence of population expansion during Pleistocene glaciation (Abyzova et al, 2018).…”

The Small Giant Clam, Tridacna maxima Exhibits Minimal Population Genetic Structure in the Red Sea and Genetic Differentiation From the Gulf of Aden

“…To examine the phylogenetic relationships, haplotype networks were drawn in PopArt 1 using the TCS (Templeton et al, 1992) network approach (95% parsimony connection limit) with the algorithm described by Clement et al (2002) to determine the ancestral haplotype according to the neutral coalescent theory. The haplotypes were grouped into haplogroups based on the number of mutational steps and abundant haplotypes connected to several singletons (see Abyzova et al, 2018) as well as the Bayesian inference of phylogeny. The frequencies of each haplogroup were calculated for each sample site and transformed into pie charts on the map (see Figure 2).…”

Integrated Assessment of Ocean Acidification Risks to Pteropods in the Northern High Latitudes: Regional Comparison of Exposure, Sensitivity and Adaptive Capacity

“…Global haplotype divergence was small, with most haplotypes differing from each other by a few mutations (Supplementary Figure 3). However, two previously described haplogroups (Abyzova et al, 2018;Shimizu et al, 2018) described the data, with evidence of a unique haplogroup limited to Svalbard and the Kara Sea, and dominance of the second haplogroup in the Bering Sea, Amundsen Gulf and North Pacific Seas. While the haplogroups differ by only a few mutations, these data suggests separate colonization and divergence events and broad-scale population structure.…”