Genetic Diversity and Population Structure of the Antarctic Toothfish, Dissostichus mawsoni, Using Mitochondrial and Microsatellite DNA Markers

The Antarctic toothfish, Dissostichus mawsoni, serves as a valuable fishery resource around the Antarctic Continent since 1997, managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Although delineating genetic or stock structure of populations is crucial for improving fishery management of this species, its number of genetic populations and genetic diversity levels remain ambiguous. In the present study, we assessed the population genetic and phylogeographic structure of the Antarctic toothfish across 20 geographic localities spanning from Subareas 88 (88.1, 88.2, and 88.3) to Subareas 58 (58.4 and 58.5) by using mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and 16S rRNA (16S) sequences and seven nuclear microsatellite loci. MtDNA revealed a low level of polymorphism (h = 0.571, π = 0.0006) with 40 haplotypes in 392 individuals, connected only by 1–5 mutational steps, which is indicative of shallow evolutionary history. Microsatellites showed a range of allelic richness (AR) from 6.328 (88.3 RB3) to 7.274 (88.3 RB6) within populations. Overall genetic diversity was generally higher in Subareas 58 than in Subareas 88, suggesting that effective population size (NE) is larger in Subareas 58. The results of population analyses using microsatellites suggest that the sampled populations are likely to comprise a well-admixed single gene pool (i.e., one genetic stock), perhaps due to high contemporary gene flow occurring during the prolonged larval phase of this fish. However, given weak, but significant microsatellite differentiation found in six population-pairs, the possibility of existence of multiple genetic populations could not be completely excluded. The mtDNA AMOVA suggests a genetic break between the Subareas 88 and 58 groups (FCT = 0.011, P = 0.004). Moreover, mtDNA genetic distances (FST) between populations were proportionally greater as geographic distances increase. The patterns of isolation by distance (IBD) shown only in mtDNA, but not in microsatellites might suggest that population differentiation or divergence processes underwent faster in mtDNA than microsatellites, due to its NE being only one-quarter of nuclear DNA. Temporal stability in the genetic structure of D. mawsoni is also indicated by the results of no genetic differentiation between juveniles and adults. The findings of this study will help to design effective stock management strategies for this valuable fishery resource. We suggest that a long-term genetic monitoring is needed to understand the population structure and dynamics of toothfish in response to ongoing climate changes.

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Population subdivision in the Antarctic toothfish (Dissostichus mawsoni) revealed by mitochondrial and nuclear single nucleotide polymorphisms (SNPs)

Antarctic Science ◽

10.1017/s0954102008000965 ◽

2008 ◽

Vol 20 (4) ◽

pp. 327-338 ◽

Cited By ~ 16

Author(s):

Kristen L. Kuhn ◽

Patrick M. Gaffney

Keyword(s):

Population Structure ◽

Nuclear Gene ◽

South Shetland Islands ◽

Population Subdivision ◽

Preliminary Evaluation ◽

Antarctic Polar Front ◽

Antarctic Toothfish ◽

Single Nucleotide ◽

Dissostichus Mawsoni ◽

The Antarctic

AbstractThe Antarctic toothfish (Dissostichus mawsoni) exhibits a circumpolar distribution in coastal waters south of the Antarctic Polar Front. For a preliminary evaluation of global population structure in this species, we examined four mitochondrial regions and 13 nuclear gene fragments in samples from four CCAMLR Subareas in the Southern Ocean (Australian Antarctic Territory (Subarea 58.4.2), Ross Dependency (Subareas 88.1 and 88.2) and the South Shetland Islands (Subarea 48.1). Significant genetic differentiation within and among locations was observed for both mitochondrial and nuclear loci. The single nucleotide polymorphism (SNP) markers developed here will be useful for more extensive analyses of population structure in this species.

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A new deep-sea fish leech of the bipolar genus Pterobdellina stat. rev. (Hirudinea: Piscicolidae) parasitic on the Antarctic toothfish Dissostichus mawsoni (Perciformes: Nototheniidae)

Marine Biodiversity ◽

10.1007/s12526-020-01140-1 ◽

2021 ◽

Vol 51 (1) ◽

Author(s):

Аndriy Utevsky ◽

Roman Solod ◽

Serge Utevsky

Keyword(s):

Deep Sea ◽

Antarctic Toothfish ◽

Dissostichus Mawsoni ◽

The Antarctic ◽

Sea Fish

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Spatial distribution and population structure of juvenile Antarctic toothfish (Dissostichus mawsoni) in the South Shetland Islands

Polar Biology ◽

10.1007/s00300-019-02602-4 ◽

2019 ◽

Vol 42 (12) ◽

pp. 2237-2247

Author(s):

Mario La Mesa ◽

Emilio Riginella ◽

Christopher D. Jones

Keyword(s):

Population Structure ◽

Spatial Distribution ◽

South Shetland Islands ◽

The South ◽

Antarctic Toothfish ◽

Shetland Islands ◽

Dissostichus Mawsoni

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High genetic diversity but no geographical structure of Aedes albopictus populations in Réunion Island

Parasites & Vectors ◽

10.1186/s13071-019-3840-x ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Anne C. Latreille ◽

Pascal Milesi ◽

Hélène Magalon ◽

Patrick Mavingui ◽

Célestine M. Atyame

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Aedes Albopictus ◽

Genetic Variance ◽

Mosquito Control ◽

Isolation By Distance ◽

Virus Transmission ◽

Reunion Island ◽

High Genetic Diversity ◽

Réunion Island

Abstract Background In recent years, the Asian tiger mosquito Aedes albopictus has emerged as a species of major medical concern following its global expansion and involvement in many arbovirus outbreaks. On Réunion Island, Ae. albopictus was responsible for a large chikungunya outbreak in 2005–2006 and more recently an epidemic of dengue which began at the end of 2017 and is still ongoing at the time of writing. This dengue epidemic has seen a high number of human cases in south and west coastal regions, while few cases have been reported in the north and east of the island. To better understand the role of mosquito populations in such spatial patterns of dengue virus transmission in Réunion Island, we examined the genetic diversity and population structure of Ae. albopictus sampled across the island. Results Between November 2016 and March 2017, a total of 564 mosquitoes were collected from 19 locations in three main climatic regions (West, East and Center) of Réunion Island and were genotyped using 16 microsatellite loci. A high genetic diversity was observed with 2–15 alleles per locus and the average number of alleles per population varying between 4.70–5.90. Almost all FIS values were significantly positive and correlated to individual relatedness within populations using a hierarchical clustering approach based on principal components analyses (HCPC). However, the largest part of genetic variance was among individuals within populations (97%) while only 3% of genetic variance was observed among populations within regions. Therefore, no distinguishable population structure or isolation by distance was evidenced, suggesting high rates of gene flow at the island scale. Conclusions Our results show high genetic diversity but no genetic structure of Ae. albopictus populations in Réunion Island thus reflecting frequent movements of mosquitoes between populations probably due to human activity. These data should help in the understanding of Ae. albopictus vector capacity and the design of effective mosquito control strategies.

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Genetic diversity of the lichen-forming alga, Diplosphaera chodatii, in North America and Europe

The Lichenologist ◽

10.1017/s0024282913000510 ◽

2013 ◽

Vol 45 (6) ◽

pp. 799-813 ◽

Cited By ~ 7

Author(s):

Kyle M. FONTAINE ◽

Elfie STOCKER-WÖRGÖTTER ◽

Tom BOOTH ◽

Michele D. PIERCEY-NORMORE

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Gene Flow ◽

North America ◽

Isolation By Distance ◽

Water Level Fluctuations ◽

Free Living ◽

Climatic Zones ◽

Algal Symbiont ◽

Low Levels

AbstractDermatocarpon luridum is a subaquatic lichen which is distributed within temperate climatic zones around the world. It colonizes rock substrata along the shoreline of lakes and rivers of watersheds that regularly experience water level fluctuations. The mycobiont produces perithecia with small, simple spores that are thought to be wind dispersed. The photobiont, Diplosphaera chodatii, occurs both free-living and lichenized but little is known about its distribution and dispersal. The goal of this study was to compare the population structure of the photobiont from lakes and rivers in central North America with those of Europe. Specimens were collected in Manitoba, Canada and Austria. Population structure of the algal symbiont was assessed using the internal transcribed spacer (ITS) of ribosomal DNA (rDNA) and actin gene sequences. Results showed that genetic diversity and gene flow was high within local populations, but gene flow was low between continental populations. Low levels of gene flow between the most distant populations support the isolation-by-distance theory. The photobiont on both continents is also reported to be the photobiont for other lichen species contributing to photobiont availability for D. luridum.

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Assembly of the antifreeze glycoprotein/trypsinogen-like protease genomic locus in the Antarctic toothfish Dissostichus mawsoni (Norman)

Genomics ◽

10.1016/j.ygeno.2011.06.002 ◽

2011 ◽

Vol 98 (3) ◽

pp. 194-201 ◽

Cited By ~ 14

Author(s):

Jessie Nicodemus-Johnson ◽

Stephen Silic ◽

Laura Ghigliotti ◽

Eva Pisano ◽

C.-H. Christina Cheng

Keyword(s):

Antarctic Toothfish ◽

Genomic Locus ◽

Antifreeze Glycoprotein ◽

Dissostichus Mawsoni ◽

The Antarctic

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Population structure of Friesea grisea (Collembola, Neanuridae) in the Antarctic Peninsula and Victoria Land: evidence for local genetic differentiation of pre-Pleistocene origin

Antarctic Science ◽

10.1017/s0954102010000775 ◽

2010 ◽

Vol 22 (6) ◽

pp. 757-765 ◽

Cited By ~ 18

Author(s):

Giulia Torricelli ◽

Francesco Frati ◽

Peter Convey ◽

Marco Telford ◽

Antonio Carapelli

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Genetic Structure ◽

Antarctic Peninsula ◽

West Antarctica ◽

Genetic Structure Of Populations ◽

Victoria Land ◽

Springtail Species ◽

Ancestral Haplotypes ◽

The Antarctic

AbstractFriesea grisea is the only springtail species currently described from both East (Victoria Land) and West Antarctica (Antarctic Peninsula), although levels of genetic divergence between the two regions suggest the possibility of cryptic species. Determining the genetic structure of populations in the two regions is necessary in order to compare the effects of the different environmental conditions in the two regions, the different evolutionary histories of their inhabitants, and for assessing any influence of latitude in each region on genetic diversity. We analysed sequences of the mitochondrial COX1 and ATP6 genes from a total of 111 individuals for 17 sites (nine on the Antarctic Peninsula and eight in Victoria Land), to assess levels of genetic diversity. Both regions have their own unique sets of haplotypes, differing by about 20% of their nucleotide sequences. A similar number of haplotypes was found in the two regions, and within each we found two groups of populations sharing no haplotypes. In the Antarctic Peninsula, two, presumably ancestral, haplotypes are dominant in frequency. In Victoria Land, the Cape Hallett population showed a distinct set of haplotypes, genetically different from the southernmost populations, suggesting differentiation on pre-Pleistocene timescales.

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Metabarcoding analysis of the stomach contents of the Antarctic Toothfish (Dissostichus mawsoni) collected in the Antarctic Ocean

PeerJ ◽

10.7717/peerj.3977 ◽

2017 ◽

Vol 5 ◽

pp. e3977 ◽

Cited By ~ 6

Author(s):

Tae-Ho Yoon ◽

Hye-Eun Kang ◽

Soo Rin Lee ◽

Jae-Bong Lee ◽

Gun Wook Baeck ◽

...

Keyword(s):

Fish Species ◽

Dna Barcode ◽

Stomach Contents ◽

Antarctic Ocean ◽

Antarctic Toothfish ◽

Dissostichus Mawsoni ◽

Morphological Studies ◽

The Antarctic ◽

Prey Items

Stomach contents of the Antarctic toothfish, Dissostichus mawsoni, collected from subareas 58.4 and 88.3, were analyzed using next generation sequencing (NGS) technology. After processing the raw reads generated by the MiSeq platform, a total of 131,233 contigs (130 operational taxonomic units [OTUs]) were obtained from 163 individuals in subarea 58.4, and 75,961 contigs (105 OTUs) from 164 fish in subarea 88.3. At 98% sequence identity, species names were assigned to most OTUs in this study, indicating the quality of the DNA barcode database for the Antarctic Ocean was sufficient for molecular analysis, especially for fish species. A total of 19 species was identified from the stomach of D. mawsoni in this study, which included 14 fish species and five mollusks. More than 90% of contigs belonged to fish species, supporting the postulate that the major prey of D. mawsoni are fish. Two fish species, Macrourus whitsoni and Chionobathyscus dewitti, were the most important prey items (a finding similar to that of previous studies). We also obtained genotypes of prey items by NGS analysis, identifying an additional 17 representative haplotypes in this study. Comparison with three previous morphological studies and the NGS-based molecular identification in this study extended our knowledge regarding the prey of D. mawsoni, which previously was not possible. These results suggested that NGS-based diet studies are possible, if several current technical limitations, including the quality of the barcode database or the development of precise molecular quantification techniques to link them with morphological values, are overcome. To achieve this, additional studies should be conducted on various marine organisms.

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Population connectivity and larval dispersal of the exploited mangrove crab Ucides cordatus along the Brazilian coast

PeerJ ◽

10.7717/peerj.4702 ◽

2018 ◽

Vol 6 ◽

pp. e4702 ◽

Cited By ~ 4

Author(s):

Fábio B. Britto ◽

Anders J. Schmidt ◽

Adriana M.F. Carvalho ◽

Carolina C.M.P. Vasconcelos ◽

Antonia M. Farias ◽

...

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Gene Flow ◽

Population Connectivity ◽

Brazilian Coast ◽

Fishery Resource ◽

Ucides Cordatus ◽

Migration Rates ◽

Mangrove Crab ◽

Key Species

Background The mangrove crab Ucides cordatus is considered a key species for the ecological balance of mangrove forests and a major source of employment and income for traditional crab collectors in Brazil. Several studies evidenced weak genetic variation among populations due to an efficient larval transport. However, gene flow patterns of the species is poorly understood, with no information about migration rates. The influence of the two main Brazilian currents in larval dispersion is also not clear. In order to provide baseline information for conservation, planning and management of this important fishery resource, the present study aimed to estimate and evaluate spatial distribution of genetic diversity, migration rates and gene flow directivity among populations of U. cordatus in Brazil. Methods Nine microsatellites were used to resolve population structure of 319 crabs collected from six sites located along the Brazilian coast. The degree of geographical differentiation included estimates of genetic diversity, population structure and gene flow models, with spatial analysis of shared alleles (SAShA), isolation by distance tests, AMOVA, discriminant analysis of principal components (DAPC) and Bayesian clustering. We estimated the amount of ongoing gene flow between clusters using the coalescent-based method implemented in Migrate-N. Results Loci were highly polymorphic (average of 12.4 alleles per locus) evidencing high genetic variability. There was significant differentiation among localities, despite of the low value of FST (= 0.019; P < 0.001). FST and Jost’s D indexes were also estimated in pairwise comparisons and showed significant differences between most of the surveyed site pairs (P < 0.05). Structure evidenced a single genetic group among samples, however SAShA pointed to a non-panmictic condition (P = 0.011). AMOVA detected four statistical significant clusters with low level of differentiation (FCT = 0.037; P = 0.023). The gene flow model that best described the population connectivity was the island model, with ∼24 crabs being exchanged among localities per generation. Discussion The high migration rates found among localities seem to be the main force acting to sustain the distribution of the genetic diversity of U. cordatus. Despite the high gene flow and the weak population structure among samples, the significant genetic differences found suggest that gene flow alone does not bypass the effects of genetic drift, natural selection and/or human exploitation. These findings are vital for the establishment of a database to be used in the development of conservation programs.

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