• Journal of Life Science
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• v.16 no.2 s.75
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• pp.213-218
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• 2006

The study of genetic diversity and population structure was carried out in the Codium fragile using allozyme analysis. Although this species has been regarded as a ecologically and economically important source, there is no report on population structure in Korea. Starch gel electrophoresis was used to investigate the allozyme variation and genetic structure of four Korean populations of this species. Of the 15 genetic loci surveyed, nine (60.0%) was polymorphic in at least one population. Genetic diversity was high at the species level ($H_{ES}$=0.144), and, that of the population level was relatively low ($H_{EP}$=0.128). Nearly 87% of the total genetic diversity in C. fragile was apportioned within populations. The predominant asexual reproduction, population fragmentation, low fecundity, geographic isolation and colonization process are proposed as possible factors contributing to low genetic diversity in this species. The indirect estimated of gene flow based on $G_{ST}$ was 1.69. The moderate level of gene flow in C. fragile populations is mainly caused by thallus developed from isolated utricles dispersal via sea current.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.246-254
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• 1991

Genetic structure of a Pinus densiflora population consisting of two subpopulations on the north-and south-facing slopes of a mountain was studied by allozyme analysis. Allozyme variants in aspartate aminotransferase(AAT), glutmate dehydrogenase(GDH) and leucine aminopeptidase(LAP) systems are encoded, at least, by eight loci ; five for AAT, one for GDH and two for LAP. Average number of alleles examined over six loci was 3.33. Average heterozygosity and genetic diversity computed over six loci were, respectively, 0.19 and 2.76 for parental population, 0.17 and 2.22 for progeny population. Differences in allelic frequencies between maternal sources at many of the investigated loci were found and between subpopulations on the north- and south-facing slopes. Allele frequencies of maternal origin at some of the loci were significantly different from each other between the two subpopulations. Thus it appears that the matings within and between subpopulations were not random and the mountain ridge that divides the north-and south-facing slopes isolate the two suhpopulations reproductively to a great extent. Some of the genotypes both in parental and progeny(embryo) groups deviate significantly from the Hardy-Weinberg equilibrium state. It appears from the result that the pine population is originated from a few limited ancestral trees and thus consanguineous matings are prevalent in this pine population.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.242-247
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• 1989

This study was conducted to estimate the inheritance of allozyme variants in IDH, ME and PGI, using megagametophyte tissue of seeds of Pinus densiflora and Pinus thunbergii in Kyungpook province. Two alleles at a single locus were detected for MH in Pinus densiflora, but Pinus thunbergii showed no varition, showing only one band. Four alleles at one locus were determined for ME in Pinus densiflora and Pinus thunbergii. Two loci were found for PGI and no variation seemed to occurred in A-locus as the presence of one single band. Five alleles were presented in B-locus in Pinus densiflora, but two alleles $B_1$ and $B_2$ in Pinus thunbergii. In PGI, an allozyme composed of multiple bands is observed from haploid megagamtophyte tissues. The isozyme variants of IDH, ME and PGI were appeared to segregate into 1 : 1 ratio for all zones.

• Korean Journal of Plant Taxonomy
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• v.49 no.2
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• pp.118-126
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• 2019

The taxonomic rank of the tiny-leaved terrestrial orchid Cephalanthera subaphylla Miyabe & $Kud{\hat{o}}$ has been somewhat controversial, as it has been treated as a species or as an infraspecific taxon, under C. erecta (Thunb.) Blume [C. erecta var. subaphylla (Miyabe & $Kud{\hat{o}}$) Ohwi and C. erecta f. subaphylla (Miyabe & $Kud{\hat{o}}$) M. Hiro]. Allozyme markers, traditionally employed for delimiting species boundaries, are used here to gain information for determining the taxonomic status of C. subaphylla. To do this, we sampled three populations of five taxa (a total of 15 populations) of Cephalanthera native to the Korean Peninsula [C. erecta, C. falcata (Thunb.) Blume, C. longibracteata Blume, C. longifolia (L.) Fritsch, and C. subaphylla]. Among 20 putative loci resolved, three were monomorphic (Dia-2, Pgi-1, and Tpi-1) across the five species. Apart from C. longibracteata, there was no allozyme variation within the remaining four species. Of the 51 alleles harbored by these 17 polymorphic loci, each of the 27 alleles at 14 loci was unique to a single species. Accordingly, we found low average values of Nei's genetic identities (I) between ten species pairs (from I = 0.250 for C. erecta versus C. longifolia to I = 0.603 for C. falcata vs. C. longibracteata), with C. subaphylla being genetically clearly differentiated from the other species (from I = 0.349 for C. subaphylla vs. C. longifolia to 0.400 for C. subaphylla vs. C. falcata). These results clearly indicate that C. subaphylla is not genetically related to any of the other taxa of Cephalanthera that are native to the Korean Peninsula, including C. erecta. In a principal coordinate analysis (PCoA), C. subaphylla was positioned distant not only from C. falcata, C. longibracteata, and C. longifolia, but also from C. erecta. Finally, K = 5 was the best clustering scheme using a Bayesian approach, with five clusters precisely corresponding to the five taxa. Thus, our allozyme results strongly suggest that C. subaphylla merits the rank of species.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1188-1191
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• 2004

Two species of marine catfish, Arius maculatus and Osteogeneiosus militaris, belonging to family Ariidae were analysed electrophoretically for genetic variation in 6 enzymes, alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), lactate dehydrogenase (LDH), glucose dehydrogenase (GDH), malic enzyme (ME) and superoxide dismutase (SOD). Eighteen individuals of each species were studied. Two loci MDH and ADH were polymorphic in both. Average heterozygosity in A. maculatus was 1.46, while it was 2.5 in O. militaris. The allele frequencies were used to estimate Nei's genetic distance (D). The D value was calculated to be 0.6879. Two isozyme loci, ME and SOD, were found to be the most reliable species specific markers. No tissue specific loci were observed for the enzymes studied, the bands being identical in each case. The genetic distance observed between O. militaris and A. maculatus in this study suggests that they would be more appropriately classified as species of the same genus rather than being assigned separate genera.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1266-1275
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• 2010

Isozyme and protein electrophoresis data from mycelial extracts of 27 isolates of Trichoderma harzianum, 10 isolates of T. aureoviride, and 10 isolates of T. longibrachiatum from Southern Peninsular Malaysia were investigated. The eight enzyme and a single protein pattern systems were analyzed. Three isozyme and total protein patterns were shown to be useful for the detection of three Trichoderma species. The isozyme and protein data were analyzed using the Nei and Li Dice similarity coefficient for pairwise comparison between individual isolates, species isolate group, and for generating a distance matrix. The UPGMA cluster analysis showed a higher degree of relationship between T. harzianum and T. aureoviride than to T. longibrachiatum. These results suggested that the T. harzianum isolates had high levels of genetic variation compared with the other isolates of Trichoderma species.

• Animal cells and systems
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• v.1 no.4
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• pp.535-538
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• 1997

Allozyme variation of seven enzyme systems was analyzed from 202 individuals from four Korean populations of Atractomorpha lata. These populations exhibit higher levels of values of in most other insects with a mean 64% of polymorphic loci and a mean 0.384 of expected heterozygosity within populations. Fixation indices indicated considerable substructuring within populations sampled (mean $F_{is}=0.403)$, indicating probable inbreeding or assortative mating coupled with restricted migration between subpopulations. This was supported by the field observation that the species exists as small, discrete colonies in meadow habitats and females carry males. In addition, significant differences in allere frequencies between males and females at polymorphic loci examined (70%, 16 of 23 cases) could account for the observed heterozygote deficiencies.

• Journal of Environmental Science International
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• v.7 no.3
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• pp.243-250
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• 1998

We examined the genetic variation within the species, the patterns of genetic diversty between populations, thermostability variations of enzymes and temperature tolerances of Corbicula japonica from the two main rivers In Korea. Starch gel electrophoresis was used to examine the genetic variation of 22 locl. Henting experiments of electrophoresis under the condition of 40$\pm$5$^{\circ}$ for 15$\pm$5 min disclose thermostabllity differences, called heat-sensitive and heat-resistant types, within each 디ectrophoretic allozyme. Genetic diversity at the natural species level was high (77.3%), whereas the extent of heat-treat groups was relatively low (52.6%). The genetic diversity trends to decrease from the source of two main siderable high genetic diversity compared with a mean value of C. japonica species, It is recommended that several populations of the species in Korea should be preserved.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.247-252
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• 2006

For the spring ephemeral and myrmecochorous perennia, Corydalis filistipes Nakai (Fumariaceae), rare and narrow endemic to Ullung Island in Korea, genetic diversity and structure of 4 subpopulations of the species were investigated with allozyme markers. Levels of genetic diversity (A=1.73, $P_{95%}$=61..2%, Ho=0.201, He=0.167) were relatively lower than those of other endemic species with widespread distribution range, but considerably higher than other endemic species with similar life history traits isolated in island. The moderate level of genetic diversity within subpopulations in C. filistipes is characteristic of the species with predominantly outcrossing, myrmecochorous seed dispersal by dual function of the elaisome and mode of sexual and asexual reproduction by the cleistogamy. The analysis of fixation indices showed an overall excess of heterozygotes (mean $F_{IS}=-0.1889,\;F_{IT}=-0.1226$) relative to H-W expectations. About 5.6% of the total genetic variation was found among subpopulations ($F_{ST}$=0.0557). The strategies of reasonable conservation and management, and the maintenance mechanism of genetic diversity of Corydalis filistipes Nakai, endemic plant species in Korea were discussed.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.235-243
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• 2001

Genetic variation of the beet armyworm, Spodoptera exigua (Hubner), was analyzed by polymorphic allozymes. Field populations were subdivided by different hosts, geographical locations, and seasons. Estimated average heterozygosity ($0.443\pm$0.013) indicated high genetic variation in all field populations of S. exigua. There were significant inbreeding effects deviated from Hardy-Weinberg equilibrium in each of subpopulations. These significant nonrandom matings were caused by within-subpopulations probably due to sampling errors, but not by mating isolation among subpopulations. Wrights ($F_{ST}$ ) and Neis (D) genetic distances indicated little genetic differentiation among subpopulations, though some southern local subpopulations (Haenam and Sachon) were relatively different of northern subpopulations (Andong and Kunwi). Estimated number of migrants per generation was 5.9 among host subpopulations, 10.6 among geographical subpopulations, and 31.8 among seasonal subpopulations. These genetic analyses suggest that Korean S. exigua subpopulations have little genetic differentiation mostly due to their significant migratory capacity.