• Journal of Aquaculture
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• v.7 no.4
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• pp.207-223
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• 1994

Induction of triploid cherry salmon, Oncorhynchus ma.sou was performed by the heat shock procedure. The triploids were induced by 15 and 20 min heat shock treatments after 10 min fertilization at $28^{\circ}C$. Incidences of the triploidy were $91.4\%\;and\;89.8\%$, respectively. Nucleus and erythrocyte from the induced triploids larger than those of the diploids in major axis, minor axis, major axis/minor axis, surface area and volume. The chromosome number of diploid was 2n= 66 (17 pairs of metacentrics or submetacentrics, 16 pairs of acrocentrics or telocentrics), and that of triploid was 3n=99. Satellites were observed in the short arm of the largest telocentrics, and these may be useful marker to determine the polyploidization. Diploid have outgrown to triploid, and female have also outgrown to male in the triploid group during the 22 months of observation period after hatching. During the spawning season, 22 to 26 months after hatching, diploid were observed the growth retardation because of their sexual maturation, however the triploid showed continuous growth.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.300-304
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• 2008

Cysteine proteinases play an essential role in plant growth and development but also in senescence and programmed cell death. They participate in both anabolic and catabolic processes. In addition, they are involved in signalling pathways and in the response to biotic and abiotic stresses. A cDNA clone encoding cysteine proteinase (CP) gene, designated PgCysP1, was isolated from Panax ginseng C. A. Meyer. Reverse transcriptase (RT)-PCR results showed that PgCysP1 expressed at different level in P. ginseng hairy root. Different stresses such as biotic as well as abiotic stresses triggered a significant induction of PgCysP1. The positive responses of PgCysP1 to the various stimuli suggested that PgCysP1 may help to protect the plant against reactive environmental stresses.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.40-56
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• 2023

Tree species within the Populus genus grow rapidly and have an excellent capacity to absorb carbon, conferring substantial ability to effective purify the environment. Poplar breeding can be achieved rapidly and efficiently if a genetic linkage map is constructed and quantitative trait loci (QTLs) are identified. Here, a high-density genetic linkage map was constructed for the control pollinated progeny using the genotyping-by-sequencing (GBS) technique, which is a next-generation sequencing method. A search was also performed for the genes associated with quantitative traits located in the genetic linkage map by examining the variables of height and diameter at root collar, and resilience to insect damage. The height and diameter at root collar were measured directly, while the ability to recover from insect damage was scored in a 4-year-old breeding population of aspen hybrids (Odae19 × Bonghyeon4 F1) established in the research forest of Seoul National University. After DNA extraction, paternity was confirmed using five microsatellite markers, and only the individuals for which paternity was confirmed were used for the analysis. The DNA was cut using restriction enzymes and the obtained DNA fragments were prepared using a GBS library and sequenced. The analyzed results were sorted using Populus trichocarpa as a reference genome. Overall, 58,040 aligned single-nucleotide polymorphism (SNP) markers were identified, 17,755 of which were used for mapping genetic linkages. The genetic linkage map was divided into 19 linkage groups, with a total length of 2,129.54 cM. The analysis failed to identify any growth-related QTLs, but a gene assumed to be related to recovery from insect damage was identified on linkage group (chromosome) 4 through genome-wide association study.

• Journal of Life Science
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• v.22 no.3
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• pp.366-372
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• 2012

This study was conducted to estimate the extent of linkage disequilibrium (LD) and effective population size using whole genomic single nucleotide polymorphisms (SNP) genotyped by DNA chip in Hanwoo. Using the blood samples of 35 young bulls born from 2005 to 2008 and their progenies (N=253) in a Hanwoo nucleus population collected from Hanwoo Improvement Center, 51,582 SNPs were genotyped using Bovine SNP50 chips. A total of 40,851 SNPs were used in this study after elimination of SNPs with a missing genotyping rate of over 10 percent and monomorphic SNPs (10,730 SNPs). The total autosomal genome length, measured as the sum of the longest syntenic pairs of SNPs by chromosome, was 2,541.6 Mb (Mega base pairs). The average distances of all adjacent pairs by each BTA ranged from 0.55 to 0.74 cM. Decay of LD showed an exponential trend with physical distance. The means of LD ($r^2$) among syntenic SNP pairs were 0.136 at a range of 0-0.1 Mb in physical distance and 0.06 at a range of 0.1-0.2 Mb. When these results were used for Luo's formula, about 2,000 phenotypic records were found to be required to achieve power > 0.9 to detect 5% QTL in the population of Hanwoo. As a result of estimating effective population size by generation in Hanwoo, the estimated effective population size for the current status was 84 heads and the estimate of effective population size for 50 generations of ancestors was 1,150 heads. The average decreasing rates of effective population size by generation were 9.0% at about five generations and 17.3% at the current generation. The main cause of the rapid decrease in effective population size was considered to be the intensive use of a few prominent sires since the application of artificial insemination technology in Korea. To increase and/or sustain the effective population size, the selection of various proven bulls and mating systems that consider genetic diversity are needed.