• Asian-Australasian Journal of Animal Sciences
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• 제33권12호
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• pp.1912-1921
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• 2020

Objective: This study assessed genomic prediction accuracies based on different selection methods, evaluation procedures, training population (TP) sizes, heritability (h²) levels, marker densities and pedigree error (PE) rates in a simulated Korean beef cattle population. Methods: A simulation was performed using two different selection methods, phenotypic and estimated breeding value (EBV), with an h² of 0.1, 0.3, or 0.5 and marker densities of 10, 50, or 777K. A total of 275 males and 2,475 females were randomly selected from the last generation to simulate ten recent generations. The simulation of the PE dataset was modified using only the EBV method of selection with a marker density of 50K and a heritability of 0.3. The proportions of errors substituted were 10%, 20%, 30%, and 40%, respectively. Genetic evaluations were performed using genomic best linear unbiased prediction (GBLUP) and single-step GBLUP (ssGBLUP) with different weighted values. The accuracies of the predictions were determined. Results: Compared with phenotypic selection, the results revealed that the prediction accuracies obtained using GBLUP and ssGBLUP increased across heritability levels and TP sizes during EBV selection. However, an increase in the marker density did not yield higher accuracy in either method except when the h² was 0.3 under the EBV selection method. Based on EBV selection with a heritability of 0.1 and a marker density of 10K, GBLUP and ssGBLUP_0.95 prediction accuracy was higher than that obtained by phenotypic selection. The prediction accuracies from ssGBLUP_0.95 outperformed those from the GBLUP method across all scenarios. When errors were introduced into the pedigree dataset, the prediction accuracies were only minimally influenced across all scenarios. Conclusion: Our study suggests that the use of ssGBLUP_0.95, EBV selection, and low marker density could help improve genetic gains in beef cattle.

• Journal of Animal Science and Technology
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• 제44권6호
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• pp.669-676
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• 2002

유전표지인자를 이용한 선발(marker assisted selection; MAS)과 전통적인 표현형기록에 근거한 반응의 비교분석을 위하여 고정효과모델(deterministic model)을 이용하여 시뮬레이션을 하였다. 자신의 단일 기록을 이용한 경우와 자신의 기록과 자신의 표지인자 정보를 이용할 경우 유전력이 높을수록 MAS의 효율성이 38%정도 높게 나타났다. 그러나 유전력이 높은 경우(50%) MAS의 효율성은 약 1%정도로서 효율성이 대단히 낮은 것으로 나타났다. 자신의 기록과 부모의 표현형 정보에 표지인자 정보를 추가할 경우 MAS의 효율성은 27% 정도였으며 마찬가지로 유전력이 높은 경우에는 효율성이 0에 가깝게 나타났다. MAS의 효율성은 유전력이 낮을수록 그리고 이용한 표지인자의 유전적 변이가 클수록 효율성이 높아지는 것으로 나타났다.

• Journal of Plant Biotechnology
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• 제3권3호
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• pp.113-121
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• 2001

The use of a marker gene in a transformation process aims to give a selective advantage to the transformed cells, allowing them to grow faster and better, and to kill the non-transformed cells. In general, the selective gene is introduced into plant genome along with the genes of interest. In some cases, the marker gene can be the gene of interest that will confer an agronomic characteristic, such as herbicide resistance. In this review we list and discuss the use of the most common selective marker genes on plant transformation and the effects of their respective selective agents. These genes could be divided in categories according their mode of action: genes that confer resistance to antibiotics and herbicides; and genes for positive selection. The contention of the marker gene flow through chloroplast transformation is further discussed. Moreover, strategies to recover marker-free transgenic plants, involving multi-auto-transformation (MAT), co-transformation, site specific recombination and intragenomic relocation of transgenes through transposable elements, are also reviewed.

• 생명과학회지
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• 제30권3호
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• pp.239-249
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• 2020

감 꽃은 과실을 맺는 암꽃과 꽃가루를 내는 수꽃, 암술과 수술을 모두 가진 양성화가 있다. 관행 교배육종법으로 부본용 수꽃 신품종을 육성한다면 최종 선발까지 15년 정도의 장기간과 넓은 시험포장이 요구된다. 유묘기에 수꽃 착생 개체를 조기에 선발하여 육종효율을 증진하고자 꽃의 성표현을 알고 있는 주요 품종 88개체를 대상으로 Akagi 등(2014)이 보고한 수꽃 선발 마커들의 적용 효과를 검증하였다. OGI locus marker와 DISx-AF4S marker 적용 결과 각각 83품종, 72품종에서 꽃의 성표현과 분석 결과가 일치하였다. 육성품종인 '미감조생'을 모본으로 한 교배조합 등으로부터 나온 실생 2,509개체에 OGI locus marker 수꽃 선발 마커를 적용하여 890개체를 선발하였고, 분석 완료한 교배실생 중 아직 착과가 되지 않았거나 고사한 개체를 제외한 1,186개체를 대상으로 꽃의 성표현과 마커 분석 결과를 비교하였을 때 401개체가 불일치한 것을 확인하였다(33.8%). 다양한 교배조합으로부터 나온 실생 889개체에 DISx-AF4S marker를 적용하여 분석한 결과 636개체를 선발하였다. 분석 완료한 교배실생 중 아직 착과가 되지 않았거나 고사한 개체를 제외한 379개체를 대상으로 꽃의 성 표현과 마커 분석 결과를 비교하였고 247개체가 불일치한 것을 확인하였다(65.2%). 이상의 결과들을 종합하여 볼 때, 검토한 DISx-AF4S, OGI locus marker는 육종현장에서 활용하기에 유용하지 않을 것으로 판단된다.

• 한국양식학회지
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• 제18권2호
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• pp.130-132
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• 2005

Genomics research has two ultimate applied goals: to Isolate and clone genes of economic importance for bio-technology and gene-assisted selection (GAS), and to locate and use markers for marker-assisted selection (MAS) in selective breeding programs. To this end, we have identified linked markers for feed conversion efficiency growth rate, and disease resistance to enteric septicemia of catfish (ESC). Three microsatellite markers Ip266, Ip384, and Ip607 were identified to be linked to feed conversion efficiency. Similarly one marker each was identified to be linked to growth rate (Ip607) and disease resistance to ESC (Ip477). Ip607 marker linked to both growth rate and feed conversion efficiency, indicating that the QTL for both growth rate and feed conversion efficiency may either be the same or located in the same chromosomal region in the catfish genome. On phenotypic evaluation, certain traits such as growth rate can be accurately evaluated by body weight evaluation while other traits such as disease resistance can be quite complex. The linked DNA markers will be highly useful for MAS programs and for directing further efforts of genomic mapping for important quantitative traits.

• Molecules and Cells
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• 제20권1호
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• pp.30-34
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• 2005

This study was carried out to identify a high-resolution marker for a gene conferring resistance to brown planthopper (BPH) biotype 1, using japonica type resistant lines. Bulked segregant analyses were conducted using 520 RAPD primers to identify RAPD fragments linked to the BPH resistance gene. Eleven RAPDs were shown to be polymorphic amplicons between resistant and susceptible progeny. One of these primers, OPE 18, which amplified a 923 bp band tightly linked to resistance, was converted into a sequence-tagged-site (STS) marker. The STS marker, BpE18-3, was easily detectable as a dominant band with tight linkage (3.9cM) to Bph1. It promises to be useful as a marker for assisted selection of resistant progeny in backcross breeding programs to introgress the resistance gene into elite japonica cultivars.

• 한국수산과학회지
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• 제40권3호
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• pp.128-132
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• 2007

We identified a microsatellite marker, Poli121TUF, which appears to be significantly linked (P<0.001) with a lymphocystis disease virus (LCDV)-resistance gene in the olive flounder, Paralichthys olivaceus. The olive flounder is an economically important food fish, that is widely cultured in Korea, Japan, and China. Lymphocystis disease has spread in these countries and has seriously reduced the economic value of the fish. LCDV causes lymphocystis cells (LC) to form on the body surface, fins, gills, mouth, and intestine. Fish with LC lose commercial value due to their deformed appearance. The identified micro satellite marker can be used as a candidate locus for marker-assisted selection (MAS) in order to enhance the efficiency of selection for LCDV resistance in the olive flounder.

• 한국육종학회지
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• 제40권1호
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• pp.48-53
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• 2008

본 연구에서는 벼멸구 저항성 개통 육성과정 중에 수행한 PS와 MAS system간의 선발 효율을 정확성, 소요시간, 소요비용 등의 요인으로 비교 분석함으로써 MAS system의 선발 효율을 제시하고, 이를 이용하여 효과적인 MAS system을 구축하고 실용화하기 위한 방안을 제시하였다. DNA marker를 이용하여 벼멸구 저항성 개체를 선발하고 MAS 체제를 확립하기 위하여 '삼강/낙동' 조합의 $F_2$집단, RIL($F_6$), DH집단, 여교잡집단($BC_6F_5$)을 대상으로 PS와 marker 검정을 병행하여 두 검정 방법 간에 각 잡종집단 및 세대별 저항성과 감수성 계통(개체)의 비율을 비교한 바 95%이상 일치하였다. MAS 체제와 PS간의 선발효율을 비교한 바 MAS는 PS에 비해 약 32%의 비용이 절감되었고, 검정에 소요되는 기간도 기존의 PS에서는 30일인데 비해 MAS에서는 7일로 크게 단축되었다. 이 결과를 바탕으로 MAS에 의한 벼멸구 저항성 계통 선발 체계를 확립 할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.453-460
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• 2007

An overview of developments important in the future of animal breeding is discussed. Examples from the application of quantitative genetic principles to selection in chickens and mice are given. Lessons to be learned from these species are that selection for production traits in livestock must also consider selection for reproduction and other fitness-related traits and inbreeding should be minimized. Short-term selection benefits of best linear unbiased predictor methodology must be weighed against long-term risks of increased rate of inbreeding. Different options have been developed to minimize inbreeding rates while maximizing selection response. Development of molecular genetic methods to search for quantitative trait loci provides the opportunity for incorporating marker-assisted selection and introgression as new tools for increasing efficiency of genetic improvement. Theoretical and computer simulation studies indicate that these methods hold great promise once genotyping costs are reduced to make the technology economically feasible. Cloning and transgenesis are not likely to contribute significantly to genetic improvement of livestock production in the near future.

• 한국육종학회지
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• 제43권5호
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• pp.360-367
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• 2011

Beta-carotene producing transformants were produced in the background of 'Nagdongbyeo', a Japonica rice cultivar. Introgression of the carotenoid locus in the transformant, PAC4-2 into the elite cultivar 'Ilpumbyeo' was started. To initiate a backcrossing program, we surveyed 220 SSR markers and found that 38% of them were polymorphic between 'Ilpumbyeo' as a recurrent parent and the PAC4-2 as a recipient parent. The selection strategy comprising foreground and background selection was employed. First, foreground selection was practiced in $BC_1$, $BC_2$, and $BC_3$ generations using the transgene specific PCR-based marker in addition to visual scoring of the seed color. Marker-based background selection combined with phenotypic selection was employed from $BC_3F_2$ to $BC_3F_4$ generations. Blast search indicated that the transgene PAC4-2 was located between SSR markers, RM6 and RM482. 240 $BC_3F_3$ and 63 $BC_3F_4$ lines were evaluated for four agronomic traits including days to heading. Most of the lines were similar to Ilpumbyeo in agronomic traits evaluated. The percentage of PAC4-2 genome ranged from 4% to 21% with a mean of 12.5%, which was higher than the expected for an unselected $BC_3$ backcross population. This could be explained by the fact that two genes for beta-carotene and the stripe virus resistance were targeted in this study. We selected 10 representative $BC_3F_5$ lines from 63 $BC_3F_4$ lines based on agronomic traits and carotenoids content. The selection strategy would be appropriate for the introgression of beta-carotene gene in a breeding program.