• Parasites, Hosts and Diseases
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• v.59 no.2
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• pp.179-182
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• 2021

Human infection with Taenia asiatica or a hybrid between Taenia saginata and T. asiatica has not been reported in Cambodia. We detected for the first time a hybrid form between T. saginata and T. asiatica in Preah Vihear Province, Cambodia. An adult tapeworm specimen, i.e., 75 cm long strobila without scolex, was expelled from a 27-year-old man after praziquantel medication and purging. It was morphologically indistinguishable between T. saginata and T. asiatica. Several proglottids were molecularly analyzed to confirm the tapeworm species. The mitochondrial gene encoding cytochrome c oxidase subunit 1 (cox1) and nuclear genes encoding elongation factor-1α (ef1) and ezrin-radixin-moesin (ERM)-like protein (elp) were sequenced, and a single-allele analysis was performed to confirm the haploid genotype. The results revealed that our sample showed a discrepancy between the mitochondrial and 2 nuclear genes. It possessed homozygous sequences typical of T. saginata at cox1 and ef1 loci. However, it was heterozygous at the elp locus, with 1 allele in T. asiatica (elpA) and 1 in T. saginata (elpC), which indicates that it is a hybrid between T. saginata and T. asiatica. The present results confirmed the presence of a hybrid between T. saginata and T. asiatica in Cambodia and strongly suggest the existence of also 'pure' T. asiatica in Cambodia.

• Parasites, Hosts and Diseases
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• v.58 no.6
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• pp.635-645
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• 2020

Morphological and molecular characterization of clinostomid metacercariae (CMc) was performed with the specimens collected in fish from Korea and Myanmar. Total 6 batches of clinostomid specimens by the fish species and geographical localities, 5 Korean and 1 Myanmar isolates, were analyzed with morphological (light microscopy and SEM) and molecular methods (the cytochrome c oxidase 1 gene and internal transcribed spacer 1/5.8S rRNA sequence). There were some morphological variations among CMc specimens from Korea. However, some morphometrics, i.e., the size of worm body and each organ, ratio of body length to body width, and morphology of cecal lumens, were considerably different between the specimens from Korea and Myanmar. The surface ultrastructures were somewhat different between the specimens from Korea and Myanmar. The CO1 sequences of 5 Korean specimens ranging 728-736 bp showed 99.6-100% identity with Clinostomum complanatum (GenBank no. KM923964). They also showed 99.9-100% identity with C. complanatum (FJ609420) in the ITS1 sequences ranging 692-698 bp. Meanwhile, the ITS1 sequences of Myanmar specimen showed 99.9% identity with Euclinostomum heterostomum (KY312847). Five sequences from Korean specimens clustered with the C. complanatum genes, but not clustered with Myanmar specimens. Conclusively, it was confirmed that CMc from Korea were morphologically and molecularly identical with C. complanatum and those from Myanmar were E. heterostomum.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.742-750
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• 2022

This study aimed to monitor the distribution of Cobitidae in Korea by the identification of species using genetic analysis. Based on the genetic analysis, Cobitidae species in four of five domestic fish farms consisted of only Chinese muddy loach Misgurnus mizolepis, but muddy loach Misgurnus anguillicaudatus was also present it in one fish farm. In the case of imported Cobitidae species, in addition to Chinese muddy loach and muddy loach, the harmful species Paramisgurnus dabryanus, was also present. Chinese muddy loach accounted for 20%, 67%, and 60% of the S6, S7, and S8 samples, respectively. An analysis of the total length, body length, and weight showed that domestic Chinese muddy loach showed higher values than imported muddy loach, and imported Chinese muddy loach showed similar values to P. dabryanus. There were no significant differences in the country of origin of the three species. Thus, the mitochondrial cytochrome c oxidase subunit I gene sequence was analyzed and compared the verification of species identification. The three species of Cobitidae were genetically divided into three groups and determined to have genetic differences. These results indicate that it is necessary to reduce the heterogeneous mixing rate through discriminating species by genetic analysis.

• Fisheries and Aquatic Sciences
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• v.25 no.12
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• pp.601-618
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• 2022

The genus Semisulcospira is an economically and ecologically valuable freshwater resource. Among the species, Semisulcospira coreana, Semisulcospira forticosta and Semisulcospira tegulata are endemic to the Korean peninsula and Semisulcospira gottschei is widespread in Asia. Therefore, maintenance and conservation of wild populations of these snails are important. We investigated the genetic diversity and population structure of Semisulcospira based on the mitochondrial cytochrome c oxidase subunit I (COI), NADH dehydrogenase subunit 4 (ND4), and combined mitochondrial DNA (COI + ND4) sequences. All four species and various genetic makers showed a high level of haplotype diversity and a low level of nucleotide diversity. In addition, Fu's Fs and Tajima's D neutrality tests were performed to assess the variation in size among populations. Neutrality tests of the four species yielded negative Fu's Fs and Tajima's D values, except for populations with one haplotype. The minimum spanning network indicated a common haplotype for populations of S. coreana, S. tegulata and S. gottschei, whereas S. forticosta had a rare haplotype. Also, genetic differences and gene flows between populations were assessed by analysis of molecular variance and using the pairwise fixation index. Our findings provided insight into the degree of preservation of the species' genetic diversity and could be utilized to enhance the management of endemic species.

• Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.87-99
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• 2024

Global climate change, followed by an increase in anthropogenic activities in aquatic ecosystems, and species invasions, has resulted in a decline in aquatic organism biodiversity. The Batanghari River, Sumatra's longest river, is polluted by mercury-containing illegal gold mining waste (PETI), industrial pollution, and domestic waste. Several studies have provided evidence suggesting a decline in fish biodiversity within the Batanghari River. However, a comprehensive evaluation of the present status of biodiversity in this river is currently lacking. The species under investigation were identified through various molecular-based identification methods, as well as morphological identification, which involved the use of neighbor-joining (NJ) trees. All collected specimens were initially identified using morphological techniques and subsequently confirmed with molecular barcoding analysis. Morphological and DNA barcoding identification categorized all specimens (1,692) into 36 species, 30 genera and 16 families, representing five orders. A total of 36 DNA barcodes were generated from 30 genera using a 650-bp-long fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene. Based on the Kimura two-parameter model (K2P), The minimum and maximum genetic divergences based on K2P distance were 0.003 and 0.331, respectively, and the average genetic divergence within genera, families, and orders was 0.05, 0.12, 0.16 respectively. In addition, the average interspecific distance was approximately 2.17 times higher than the mean intraspecific distance. Our results showed that the COI barcode enabled accurate fish species identification in the Batanghari River. Furthermore, the present work will establish a comprehensive DNA barcode library for freshwater fishes along Batanghari River and be significantly useful in future efforts to monitor, conserve, and manage fisheries in Indonesia.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.199-209
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• 2020

In order to clarify the taxonomic status of the Korean Macroramphosus species, which were previously confused, we investigated morphological and molecular variations of Macroramphosus (18 individuals) from Korea, and Macroramphosus (35 individuals) from Japan and Taiwan, and compared with those of M. scolopax from type locality (Mediterranean Sea). Although the Korean and Japanese specimens of Macroramphosus were clearly divided into two types in the first dorsal spine length (22.8~32.1% in A-type vs. 15.6~21.4% in B-type), distance between the first dorsal fin and second dorsal fin (6.4~9.7% vs. 8.6~13.3%), and body depth (20.0~28.0% vs. 17.3~22.6%), no genetic differences among all individuals of longspine snipefish between them were found at the specific level [d=0.0~3.3% in control region (CR); 0.0~1.3% in cytochrome b (cytb); 0.0~0.5% in cytochrome c oxidase subunit I (COI)]. Whereas, they were well distinguished in genetics (9.9~11.5% in CR; 3.8~4.6% in cytb; 1.2~3.6% in COI) from those of M. scolopax in Mediterranean Sea. It needs the scientific name of the longspine snipefish (M. scolopax) in Korea be changed as M. japonicus (and/or M. sagifue). However, our results could not find evidence of consistency between morphological and mitochondrial DNA variations which suggests that their differentiation event may occur fairly recently. Further studies using more sensitive markers such as microsatellite are needed to clarify the degree of gene flow between the two types.

• Journal of Life Science
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• v.27 no.11
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• pp.1331-1339
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• 2017

DNA barcoding is the identification of a species based on the DNA sequence of a fragment of the cytochrome C oxidase subunit I (COI) gene in the mitochondrial genome. It is widely applied to assist with the sustainable development of fishery-product resources and the protection of fish biodiversity. This study attempted to verify horse-head fish (Branchiostegus japonicus) and fake horse-head fish (Branchiostegus albus) species, which are commonly consumed in Korea. For the validation of the two species, a real-time PCR method was developed based on the species' mitochondrial DNA genome. Inter-species variations in mitochondrial DNA were observed in a bioinformatics analysis of the mitochondrial genomic DNA sequences of the two species. Some highly conserved regions and a few other regions were identified in the mitochondrial COI of the species. In order to test whether variations in the sequences were definitive, primers that targeted the varied regions of COI were designed and applied to amplify the DNA using the real-time PCR system. Threshold-cycle (Ct) range results confirmed that the Ct ranges of the real-time PCR were identical to the expected species of origin. Efficiency, specificity and cross-reactivity assays showed statistically significant differences between the average Ct of B. japonicus DNA ($21.85{\pm}3.599$) and the average Ct of B. albus DNA ($33.49{\pm}1.183$) for confirming B. japonicus. The assays also showed statistically significant differences between the average Ct of B. albus DNA ($22.49{\pm}0.908$) and the average Ct of B. japonicus DNA ($33.93{\pm}0.479$) for confirming B. albus. The methodology was validated by using ten commercial samples. The genomic DNA-based molecular technique that used the real-time PCR was a reliable method for the taxonomic classification of animal tissues.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.650-657
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• 2020

We conducted a phylogeographic analysis of Korean endemic Zacco koreanus populations inhabiting the East-flowing river (Gangneung Yeongokcheon; GY, Yangyang Namdaecheon; YN), the Han River (Seomgang; SG, Soksacheon; SS), and the Nakdong River(Gilancheon; GA) using the mitochondrial DNA cytochrome oxidase I (COI) gene (619 bp). Population genetic analysis was further performed to assess the population connectivity for the GY river where there is a large number of human-made artificial weirs with several fishways. The phylogeographic analysis revealed that while the populations of the East-flowing river and those of the Han River formed a monophyletic lineage, the Nakdong River individuals represented a distinct lineage with 3.7-4.2% (mean=4.0%) genetic distance from the other lineages. The population genetic analysis of the GY showed that a mid-stream population harbored relatively higher mitochondrial diversity relative to up- and down-stream populations, and there was no genetic differentiation between these three populations. The latter findings might suggest high genetic connectivity between the populations via genetic flow along the fishways. However, an analysis using faster-evolving genetic markers, such as microsatellites, is needed to confirm the findings of high population connectivity. Our study suggests the possibility of the presence of cryptic species in Z. koreanus in the Nakdong River basin. However, further study with more individual samples as well as additional markers or even more advanced genomic tools is required to test our hypothesis. Ecological or phenotypic analyses should be conducted to test whether the observed Nakdong River lineage represents a different or cryptic species, or simply hidden, but excessive, intraspecific diversity.

• The Korean Journal of Malacology
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• v.32 no.1
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• pp.55-62
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• 2016

In this study, an attempt has been made to analyze the morphology of Cephalopods distributed in Korea and collected samples from South-East Asian countries including Thailand, Indonesia, Vietnam, and China. A phylogenetic analysis was performed using the mitochondrial gene, Cytochrome c oxidase subunit I (COI) to understand the genetic divergences of the species and validate their origins. For achieving the objectives, samples were collected directly from Thailand Hat Yai, Songkhla, Indonesia Medan, Vietnam Ho Chi Minh, and Vung Tau in August 2015 and from China in September 2015. A total of 23 species of Cephalopods were identified falling under three orders, four familyies and nine genus. The species were distributed under Order: Octopoda (1 family, 3 genus, and 9 species), Order: Sepiolioda (1 family, 2 genus, and 8 species), and Order Teuthoidea (2 family, 4 genus, and 6 species). 23 species which is 1 family 3 genus 9 species in Octopoda, 1 family 2 genus 8 species in Sepiolioda, 2 family 4 genus 6 species in Teuthoidea. Phylogenetic analysis using COI gene was conducted for 18 species. For the remaining 5 species sequencing results showed severe variation and hence were not considered further. The COI phylogenetic analysis for the 18 species of Cephalopods were found consistent with the morphological identification. The excluded species will be subjected for a further detailed analysis.

• Genes and Genomics
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• v.40 no.11
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• pp.1213-1223
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• 2018

Pelagic larval dispersal habits influence the population genetic structure of marine mollusk organisms via gene flow. The genetic information of the clam Gomphina aequilatera (short larval stage, 10 days) which is ecologically and economically important in the China coast is unknown. To determine the influence of planktonic larval duration on the genetic structure of G. aequilatera. Mitochondrial markers, cytochrome oxidase subunit i (COI) and 12S ribosomal RNA (12S rRNA), were used to investigate the population structure of wild G. aequilatera specimens from four China Sea coastal locations (Zhoushan, Nanji Island, Zhangpu and Beihai). Partial COI (685 bp) and 12S rRNA (350 bp) sequences were determined. High level and significant $F_{ST}$ values were obtained among the different localities, based on either COI ($F_{ST}=0.100-0.444$, P<0.05) or 12S rRNA ($F_{ST}=0.193-0.742$, P<0.05), indicating a high degree of genetic differentiation among the populations. The pairwise $N_m$ between Beihai and Zhoushan for COI was 0.626 and the other four pairwise $N_m$ values were >1, indicating extensive gene flow among them. The 12S rRNA showed the same pattern. AMOVA test results for COI and 12S rRNA indicated major genetic variation within the populations: 77.96% within and 22.04% among the populations for COI, 55.73% within and 44.27% among the populations for 12S rRNA. A median-joining network suggested obvious genetic differentiation between the Zhoushan and Beihai populations. This study revealed the extant population genetic structure of G. aequilatera and showed a strong population structure in a species with a short planktonic larval stage.