https://repository.kopri.re.kr/handle/201206/11588 2026-03-30T07:46:40Z https://repository.kopri.re.kr/handle/201206/12970 Title: Whole genome survey and microsatellite motif identification of Artemia franciscana Authors: Jo, Euna; Lee, Seung Jae; Choi, Eunkyung; Kim, Jinmu; Lee, Sung Gu; Lee, Jun Hyuck; Kim, Jeong-Hoon; Park, Hyun Abstract: The genus Artemia (Crustacea: Branchiopoda: Anostraca), known as brine shrimp, is an aquatic invertebrate living mainly in salt lakes. To date, seven species have been assigned to the genus Artemia excluding the parthenogenetic populations called Artemia parthenogenetic a [1]. Artemia species are important in aquaculture industry because their dormant cysts are easily hatched, and the nauplii can be used as a nutrient-rich food for fish [2,3]. In addition, they are also widely used as aquatic model organisms for ecotoxicity tests, along with Daphnia [4?6]. However, despite the significance of Artemia in aquacul ABSTRACT Artemia is an industrially important genus used in aquaculture as a nutritious diet for fish and as an aquatic model organism for toxicity tests. However, despite the significance of Artemia, genomic research remains incomplete and knowledge on its genomic characteristics is insufficient. In particular, Artemia franciscana of North America has been widely used in fisheries of other continents, resulting in invasion of native species. Therefore, studies on population genetics and molecular marker development as well as morphological analyses are required to investigate its population structure and to discriminate closely related species. Here, we used the Illumina Hi-Seq platform to estimate the genomic characteristics of A. franciscana through genome survey sequencing (GSS). Further, simple sequence repeat (SSR) loci were identified for microsatellite marker development. The predicted genome size was ?867 Mb using K-mer (a sequence of k characters in a string) analysis (K = 17), and heterozygosity and duplication rates were 0.655 and 0.809%, respectively. A total of 421467 SSRs were identified from the genome survey assembly, most of which were dinucleotide motifs with a frequency of 77.22%. The present study will be a useful basis in genomic and genetic research for A. franciscana. 2021-03-10T00:00:00Z https://repository.kopri.re.kr/handle/201206/11772 Title: Chromosomal assembly of the Antarctic toothfish (Dissostichus mawsoni) genome using third-generation DNA sequencing and Hi-C technology Authors: Lee, Seung Jae; Kim, Jeong-Hoon; Jo, Euna; Choi, Eunkyung; Kim, Jinmu; Choi, Seok-Gwan; Chung, Sangdeok; Kim, Hyun-Woo; Park, Hyun Abstract: The Antarctic toothfish, Dissostichus mawsoni, belongs to the Nototheniidae family and is distributed in sub-zero temperatures below S60° latitude in the Southern Ocean. Therefore, it is an attractive model species to study the stenothermal cold-adapted character state. In this study, we successfully generated highly contiguous genome sequences of D. mawsoni, which contained 1 062 scaffolds with a N50 length of 36.98 Mb and longest scaffold length of 46.82 Mb. Repetitive elements accounted for 40.87% of the genome. We also inferred 32 914 protein-coding genes using in silico gene prediction and transcriptome sequencing and detected splicing variants using Isoform-Sequencing (Iso-Seq), which will be invaluable resource for further exploration of the adaptation mechanisms of Antarctic toothfish. This new high-quality reference genome of D. mawsoni provides a fundamental resource for a deeper understanding of cold adaptation and conservation of species 2021-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12053 Title: Verification of the Backscattering Strength Based on the Swimming Behavior of Antarctic Krill Authors: Han, Inwoo; Oh, Wooseok; La, Hyoung Sul; Choi, Seok-Gwan; Kang, Sukyung; Yoon, Euna; Lee, Kyounghoon Abstract: This study provides an estimate of the SDWBA-modelled mean target strength for given sets of krill length and swimming orientation. The range of the dB identification window for krill length was between 28 mm and 67 mm and the distribution of swimming orientation N[11.0 degrees, 4.0 degrees] was estimated to be between 0.06-10.97 dB, while the range estimated using N[53.1 degrees, 21.4 degrees], i.e., the distribution of orientation obtained under the brightest illuminance level, was 5.21-9.82 dB. The range of the dB window calculated using N[45.2 degrees, 23.0 degrees], obtained under the second brightest illuminance level, was 3.83-11.76 dB, and the range calculated with N[48.1 degrees, 23.0 degrees], obtained under the third illuminance level, was 3.83-11.76 dB. The range of the dB window calculated by N[45.9 degrees, 23.0 degrees] was 3.41-11.75 dB, and the range of the dB window for krill length ranging from 28 mm to 67 mm was 4.05-11.34 dB. In all the swimming orientations, the smaller the krill size was the lower the averaged target strength value was; likewise, the larger the krill size was the higher the averaged target strength value was. The result indicated that swimming orientation impacted greatly on the range of frequency differences of Antarctic krill. 2020-09-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12059 Title: Data Reconstruction for Remotely Sensed Chlorophyll-a Concentration in the Ross Sea Using Ensemble-Based Machine Learning Authors: Park, Jinku; Kim, Hyun-cheol; Bae, Dukwon; Jo, Young-Heon Abstract: Polar regions are too harsh to be continuously observed using ocean color (OC) sensors because of various limitations due to low solar elevations, ice effects, peculiar phytoplankton photosynthetic parameters, optical complexity of seawater and persistence of clouds and fog. Therefore, the OC data undergo a quality-control process, eventually accompanied by considerable data loss. We attempted to reconstruct these missing values for chlorophyll-a concentration (CHL) data using a machine-learning technique based on multiple datasets (satellite and reanalysis datasets) in the Ross Sea, Antarctica. This technique―based on an ensemble tree called random forest (RF)―was used for the reconstruction. The performance of the RF model was robust, and the reconstructed CHL data were consistent with satellite measurements. The reconstructed CHL data allowed a high intrinsic resolution of OC to be used without specific techniques (e.g., spatial average). Therefore, we believe that it is possible to study multiple characteristics of phytoplankton dynamics more quantitatively, such as bloom initiation/termination timings and peaks, as well as the variability in time scales of phytoplankton growth. In addition, because the reconstructed CHL showed relatively higher accuracy than satellite observations compared with the in situ data, our product may enable more accurate planktonic research 2020-06-01T00:00:00Z