• The Korean Journal of Zoology
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• v.32 no.2
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• pp.75-83
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• 1989

Surveys of electrophoretic variation in isozymes and general proteins encoded by 26 loci were conducted to assess species recognition and to estimate the degree of genic variation and species divergence for seven species of the genus Moroco inhabiting in Korea and Japan. Estimates of the average calculated heterozygosity per species of M semotilus, M sp., M percnurus, M lagowskii, M oxycephalus, M steindachneri and M jouyf are low: 0.021, 0.019, 0.051, 0.031, 0.023, 0.046, and 0.007, respectively, and observed heterozygosities are 0.038, 0.022, 0.060, 0.027, 0.025, 0.042, and 0.002, respectively. Allozyme analyses show these species to be distinct genetically with the lafter four species being more closely related one another than any one of them is to the rest of the species. However, these four species (M. lagowskii, M. oxycephalus, M. steindachneri and M jouyi), had unique genetic markers in each species to be recognized as valid species. These results contrast to the previous report of Chung et of. (1986) mainly due to their error in analyzing the isozyme pallems, particularly in MDH and PGI analyses. The genetic distances among M semotilus, M sp., and M percnurus are near the high end of the scale of such estimate for freshwater fish congeners. Based on estimated divergent time of these species of the genus Moroco (5 to 0.6 million years) it is assumed that they are speciated during late Pliocene to middle Pleistocene epoch prior to migration to Korean and Japanese waters through Paleo Amur River system.

• Animal Systematics, Evolution and Diversity
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• v.2 no.1
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• pp.63-78
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• 1986

Two species of Moroco oxycephalus and M. lagowskii were studied to examine patterns of genic variation and morphological difference within and between populations of two species, and to clarify their taxonomic status and geographic distribution. The number of scales above lateral line(SAL) was the key character to classify these species. On the average, M.lagowskii had 22 or more SAL whereas M.oxycephalus had 20 or less. Previously known character of the position of dorsal fin was found to be not appropriate to distinguish them. Five loci, Gp, st-1, Est-2, Est-3 and Got-1 , showed fixed difference electrophoretically between two species and these could be used as genetic markers to identify them. The degree of genic variation of M. oxycephalus was four fold higher(H=0.032) than that of M. lagowskii(H=0.008) but both species were far less than the average genic variation of freshwater fish in general. Rogers' genetic similarity coefficients between two species were S=0.692 and their presumed divergent time was estimated to be sbout 1.8million years ageo. Detailed survey of the geographic distribution of thses revealed that M.lagowskii was distributed in northeastern part of South Korea(Ganseong , Gangreung, Wangsan, and Oggye) and M. oxycephalus was occupied rest of the peninsula. The distrance between Oggye, the southern limit of M. lagowskii distribution , and Samwha (near Samcheog), the northern limit of M.oxycephalus, was aobut 15 Km apart and no symparty was found in between.

• The Korean Journal of Zoology
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• v.16 no.2
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• pp.97-108
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• 1973

Karyological characteristics and relative DNA values were investigated in four species of the family Cyprinidae of Korean fresh-water. The results obtained were as follows; 1) The two Hemibarus species, H. longirostris and H. labeo, had the aiploid chromosome number of 50. The compliment of former consisted of 7 metacentric, 14 submets- and subtelocentric and 4 telo- or acrocentric pairs, whereas latter had 9, 11 and 5 pairs respectively, Total arm numbers (AN) were 92 and 90. 2) In the case of two species of genus Moroce, M. oxycephalus and M. lagowskii, their diploid number and karyotype showed in identical pattern for each other (2n=50); 6 pairs of metacentrics, 14 pairs of submeta- and subtelocentrics and 5 pairs of telo- or acrocentrics. The AN of both species were 90. 3) Relative DNA values of all species were measured as about 60% that of gold fish. From the above observation, the cytogenetical character was discussed with special concern to the phylogenetic significance.

• Journal of fish pathology
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• v.33 no.2
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• pp.111-118
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• 2020

The genus Edwardsiella belonging to the family Enterobacteriaceae is a member of Gram-negative rod-shaped bacteria that cause disease in diverse aquatic organisms such as fish, amphibians and reptiles as well as avians and mammals including human throughout the world. This genus had been composed of three species, E. hoshinae, E. ictaluri and E. tarda, but recent researches erected two novel species, E. anguillarum and E. piscicida that were conventionally identified as E. tarda. In this study, we isolated seven strains belonging to the genus Edwardsiella from freshwater fishes that had been reared at inland fish farms in South Korea and investigated their biochemical characteristics and molecular phylogenetic relationships. The seven strains showed typical characteristics of four Edwardsiella species, E. anguillarum, E. ictaluri, E. piscicida and E. tarda, by biochemical analyses of Gram staining, indole and hydrogen sulfide (H2S) production, and API (Analytic Profile Index) 20E test. Molecular phylogenetic analyses inferred from DNA sequence data of both 16S ribosomal RNA (rRNA) and DNA gyrase subunit B (gyrB) genes were congruent with the biochemical characteristics. As a result, both biochemical and molecular phylogenetic analyses identified four strains isolated from three Anguilla species as E. anguillarum, E. piscicida and E. tarda, two strains from Pelteobagrus fulvidraco and Silurus asotus as E. ictaluri, and one strain from Moroco oxycephalus as E. piscicida. In this study, we isolated and successfully identified recently newly erected species, E. anguillarum and E. piscicida in addition to historically notorious pathogenic species, E. ictaluri and E. tarda. In the future study, systematic and comprehensive monitoring of the four Edwardsiella species are required for studying differences in pathogenicity among freshwater fishes.