Biology subjects

Skovrind, M.

Publications and source records attributed to Skovrind, M..

7 recordsLinked to original sources

bioRxiv2026

Habitat discontinuity and fidelity to migratory routes shape narwhal genetic structure and diversity

Rapid Arctic warming is reshaping marine ecosystems and altering the evolutionary trajectories of ice-associated species. Narwhals (Monodon monoceros) are Arctic endemics that are thought to be vulnerable to climate change. We present the first nuclear genomic assessment of narwhals across their distribution to evaluate population structure, demographic history, local adaptation, inbreeding and genetic load. Using genomes from 117 individuals, we identified three populations: Canadian Arctic Archipelago/West Greenland, Northeast Greenland/Svalbard and Southeast Greenland. Demographic reconstructions indicated low effective population size over at least 600,000 years, followed by population growth during the last glacial period. Our results suggest that population structure is maintained by habitat discontinuities and fidelity to migration routes. The latter may promote local adaptation, as genes related to long-term memory were found in regions putatively under selection in Canadian Arctic Archipelago/West Greenland narwhals, which undertake the longest migrations. Genome-wide diversity was uniformly low across populations. Inbreeding levels were inversely related to estimated population sizes. The small and rapidly declining Southeast Greenland population exhibited elevated recent inbreeding. Deleterious mutations were primarily masked in heterozygous genotypes, raising concerns for this population. Together, our results demonstrate that past climate, habitat discontinuities and migration fidelity jointly structure narwhal populations.

evolutionary biology↗

bioRxiv2025

Impact of tusk anomalies on the long-term foraging ecology of narwhals

Male narwhals are unique in having one long, spiralled tusk, while females of the species do not have a tusk. However, a small number of individuals develop tusk anomalies, including two-tusked males or females with a tusk. In this study, we combine genetic sexing and bone collagen stable isotope ({delta}13C and {delta}15N) analysis to evaluate whether these tooth anomalies impact foraging ecology. Our analysis of individuals collected in the waters around Greenland showed no systematic impacts; nine of ten two-tusked male narwhals, and all three one-tusked female narwhals were within the normal range of known isotopic diversity from the sampled geographic regions. Two specimens with other forms of unusual dentition both showed stable isotope values outside the range of narwhals, suggesting their diet was different. Our findings underscore how DNA data retrieved from museum specimens can elucidate biological questions of interest, such as the sex of anomalous individuals. They also show how stable isotope analysis can be used to assign individuals with unknown provenance to their geographic region of origin.

zoology↗

bioRxiv2024

Elucidating the sustainability of 700 years of Inuvialuit beluga whale hunting in the Mackenzie River Delta, Northwest Territories, Canada

Beluga whales play a critical role in the subsistence economies and cultural heritage of Indigenous communities across the Arctic, yet the effects of Indigenous hunting on beluga whales remains unknown. Here, we integrate paleogenomics and stable{delta} 13C and{delta} 15N isotope analysis to investigate 700 years of beluga subsistence hunting in the Mackenzie Delta area of northwestern Canada. Genetic identification of the zooarchaeological remains, which based on radiocarbon dating span three time periods (1290-1440 CE; 1450-1650 CE; 1800-1870 CE), indicate shifts across time in the sex ratio of the harvested belugas. The equal number of females and males harvested in 1450-1650 CE versus more males harvested in the two other time periods may reflect changes in hunting practices or temporal shifts in beluga availability. We find temporal shifts and sex-based differences in {delta}13C of the harvested belugas across time, suggesting historical adaptability in the foraging ecology of the whales. Although we uncovered novel mitochondrial diversity in the Mackenzie Delta belugas, we found no changes in nuclear genomic diversity nor any substructuring across time. Our findings indicate the genomic stability and continuity of the Mackenzie Delta beluga population across the 700 years surveyed, indicating the impact of Inuvialuit subsistence harvests on the genetic diversity of contemporary beluga individuals has been negligible. Significance StatementSince colonizing the Mackenzie Delta in northwestern Canada [~]1200 CE, Inuvialuit have been heavily reliant on belugas for their livelihoods and cultural heritage. However, little is known of the impact of centuries of sustained Inuvialuit subsistence hunting on the beluga population inhabiting the Mackenzie Delta. Using palaeogenomic and stable isotope analysis of zooarchaeological remains, and comparing the findings with contemporary data, we investigate temporal changes in beluga diversity, structuring, and foraging ecology. We show Inuvialuit harvests had a negligible impact on the genetic diversity of contemporary Mackenzie belugas, and highlight the applicability of combining genomic sexing and isotope analysis of zooarchaeological remains for advancing our understanding of past hunting practices and faunal ecologies.

genomics↗

bioRxiv2022

Genomic differentiation among European perch in the western Baltic Sea reflects colonization history and local adaptation

Environmental variation across the distribution of wild species can lead to local adaptations. The Baltic Sea was formed when the Fenno-Scandian ice sheet retreated around 12 thousand years ago, creating a new brackish water habitat colonised by both marine and freshwater fish species. The European perch (Perca fluviatilis) is a predatory freshwater fish with a large geographical distribution across Eurasia, where it inhabits a wide range of environmental niches. In the Baltic Sea region it has even developed a specialised brackish water phenotype that can tolerate environmental salinity levels, which are lethal to the ancestral freshwater phenotype. However, very little is known about the colonisation history and underlying genomic mechanisms facilitating the colonisation and adaptation of perch to the Baltic Sea. Here, we use Genotyping-By-Sequencing data from six freshwater and six brackish water localities to disclose the evolutionary relationship between the freshwater and brackish water phenotype. Our results show that the brackish water perch phenotype occurs in multiple distinct genetic clusters. We find that gene flow between brackish water phenotypes with full access to the sea likely led to lower levels of differentiation and higher diversity than in freshwater phenotypes. Selection analyses suggest that genomic adaptation played a role in the colonisation of the Baltic Sea and that the top three regions under selection harbour salinity tolerance genes. We also find a link between the historic salinity of the Baltic Sea and the demographic history of the brackish water phenotypes and go on to discuss the implications of our findings for management of brackish water perch in the western Baltic sea. HighlightsO_LIGBS data from 12 perch populations, six with brackish and six with freshwater origin C_LIO_LIColonisation history and differentiated gene flow shaped the current population structure C_LIO_LIThe brackish water ecotype was found in all three major genetic clades C_LIO_LITop three regions under selection harboured salinity tolerance genes C_LIO_LISalinity influenced Ne during the formation of the Baltic Sea C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/516742v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@29e5dforg.highwire.dtl.DTLVardef@b2b35borg.highwire.dtl.DTLVardef@1d3457org.highwire.dtl.DTLVardef@1574e46_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2021

Combining δ13C and δ15N from bone and dentine in marine mammal palaeoecological research: insights from toothed whales

Stable carbon ({delta}13C) and nitrogen ({delta}15N) isotope compositions of bone and dentine collagen extracted from museum specimens have been widely used to study the paleoecology of past populations. Due to possible systematic differences in stable isotope values between bone and dentine, dentine values need to be transformed into bone-collagen equivalent using a correction factor to allow comparisons between the two collagen sources. Here, we provide correction factors to transform dentine{delta} 13C and{delta} 15N values into bone-collagen equivalent for two toothed whales: narwhal and beluga. We sampled bone and tooth dentine from the skulls of 11 narwhals and 26 belugas. In narwhals, dentine was sampled from tusk and embedded tooth; in beluga, dentine was sampled from tooth.{delta} 13C and{delta} 15N were measured and intraindividual bone and dentine isotopic compositions were used to calculate correction factors for each species. We detected differences in{delta} 13C and{delta} 15N. In narwhals, we found (i) lower average{delta} 13C and{delta} 15N in bone compared with dentine; (ii) no difference in dentine{delta} 13C between tusk and embedded tooth. For belugas, we also detected lower{delta} 13C and{delta} 15N in bone compared with tooth dentine. The correction factors provided by the study enable the combined analysis of stable isotope data from bone and dentine in these species.

ecology↗

bioRxiv2021

How low can you go: sex identification from sequencing data of species lacking assembled sex chromosomes

Accurate sex identification is crucial for elucidating the biology of a species. In the absence of directly observable sexual characteristics, sex identification of wild fauna can be challenging, if not impossible. Molecular sexing offers a powerful alternative to morphological sexing approaches. Here, we present SeXY, a novel sex-identification pipeline, for very low-coverage shotgun sequencing data from a single individual. SeXY was designed to utilise low-effort screening data for sex identification and does not require a conspecific sex-chromosome assembly as reference. We assess the accuracy of our pipeline to data quantity by downsampling sequencing data from 100,000 to 1,000 mapped reads, and to reference genome selection by mapping to a variety of reference genomes of various qualities and phylogenetic distance. We show that our method is 100% accurate when mapping to a high-quality (highly contiguous N50 > 30 Mb) conspecific genome, even down to 1,000 mapped reads. For lower-quality reference assemblies (N50 < 30 Mb), our method is 100% accurate with 50,000 mapped reads, regardless of reference assembly quality or phylogenetic distance. The SeXY pipeline provides several advantages over previously implemented methods; SeXY (i) requires sequencing data from only a single individual, (ii) does not require assembled conspecific sex-chromosomes, or even a conspecific reference assembly, (iii) takes into account variation in coverage across the genome, and (iv) is accurate with only 1,000 mapped reads in many cases.

genomics↗

bioRxiv2020

Population genomics of the emerging forest pathogen Neonectria neomacrospora

The fungal pathogen Neonectria neomacrospora is of increasing concern in Europe where, within the last decade, it has caused substantial damage to forest stands and ornamental trees of the genus Abies (Mill.). Using whole-genome sequencing of a comprehensive collection of isolates, we show the extent of three major clades within N. neomacrospora, which most likely diverged around the end of the last Ice Age. We find it likely that the current European epidemic of N. neomacrospora was founded from a population belonging to the east North American clade. All European isolates (1957-2019) had a common evolutionary history, but substantial and asymmetrical gene flow from the larger American source population could be detected. The European population shows multiple signs of having gone through a bottleneck and subsequent population expansion.

genomics↗