• Title, Summary, Keyword: Breed-cross

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Evaluation of Reciprocal Cross Design on Detection and Characterization of Mendelian QTL in $F_2$ Outbred Populations

  • Lee, Yun-Mi;Kim, Eun-Hee;Kim, Jong-Joo
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.11
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    • pp.1625-1630
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    • 2007
  • A simulation study was conducted to evaluate the effect of reciprocal cross on the detection and characterization of Mendelian QTL in $F_2$ QTL swine populations. Data were simulated under two different mating designs. In the one-way cross design, six $F_0$ grand sires of one breed and 30 $F_0$ grand dams of another breed generated 10 $F_1$ offspring per dam. Sixteen $F_1$ sires and 64 $F_1$ dams were randomly chosen to produce a total of 640 $F_2$ offspring. In the reciprocal design, three $F_0$ grand sires of A breed and 15 $F_0$ grand dams of B breed were mated to generate 10 $F_1$ offspring per dam. Eight $F_1$ sires and 32 $F_1$ dams were randomly chosen to produce 10 $F_2$ offspring per $F_1$ dam, for a total of 320 $F_2$ offspring. Another mating set comprised three $F_0$ grand sires of B breed and 15 $F_0$ grand dams of A breed to produce the same number of $F_1$ and $F_2$ offspring. A chromosome of 100 cM was simulated with large, medium or small QTL with fixed, similar, or different allele frequencies in parental breeds. Tests between Mendelian models allowed QTL to be characterized as fixed (LC QTL), or segregating at similar (HS QTL) or different (CB QTL) frequencies in parental breeds. When alternate breed alleles segregated in parental breeds, a greater proportion of QTL were classified as CB QTL and estimates of QTL effects for the CB QTL were more unbiased and precise in the reciprocal cross than in the one-way cross. This result suggests that reciprocal cross design allows better characterization of Mendelian QTL in terms of allele frequencies in parental breeds.

Evaluation of Reciprocal Cross Design on Detection and Characterization of Non-Mendelian QTL in $F_2$ Outbred Populations: I. Parent-of-origin Effect

  • Lee, Yun-Mi;Lee, Ji-Hong;Kim, Jong-Joo
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.12
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    • pp.1805-1811
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    • 2007
  • A simulation study was conducted to evaluate the effect of reciprocal cross on the detection and characterization of parent-of-origin (POE) QTL in $F_2$ QTL populations. Data were simulated under two different mating designs. In the one-way cross design, six $F_0$ grand sires of one breed and 30 $F_0$ grand dams of another breed generated 10 $F_1$ offspring per dam. Sixteen $F_1$ sires and 64 $F_1$ dams were randomly chosen to produce a total of 640 $F_2$ offspring. In the reciprocal design, three $F_0$ grand sires of A breed and 15 $F_0$ grand dams of B breed were mated to generate 10 $F_1$ offspring per dam. Eight $F_1$ sires and 32 $F_1$ dams were randomly chosen to produce 10 $F_2$ offspring per $F_1$ dam, totaling 320 $F_2$ offspring. Another mating set comprised three $F_0$ grand sires of B breed and 15 $F_0$ grand dams of A breed to produce the same number of $F_1$ and $F_2$ offspring. A chromosome of 100 cM was simulated with large, medium or small QTL with fixed or different allele frequencies in parental breeds. A series of tests between Mendelian and POE models were applied to characterize QTL as Mendelian, paternal, maternal or partial expression QTL. The overall detection powers were similar between the two mating designs. However, the proportions of paternally expressed QTL that were declared as paternal QTL type were greater in the reciprocal cross design than in the one-way cross, and vice versa for Mendelian QTL. When QTL alleles were segregating in parental breeds, a significant proportion of Mendelian QTL were spuriously declared POE QTL, suggesting that care must be taken to characterize imprinting QTL in a QTL mapping population with a small number of $F_1$ parents.

Studies on the Utilization of Bivoltine Foundation Cross Males in the Preparation of Cross Breed Eggs of the Silkworm, Bombyx mori L.

  • Rajanna, K.L.;Reddy, G. Vemananda
    • International Journal of Industrial Entomology
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    • v.25 no.2
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    • pp.171-174
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    • 2012
  • In order to study the feasibility of utilizing bivoltine foundation cross (FC2) males of the silkworm as male components with Pure Mysore (PM), six foundation crosses viz,CSR2 x CSR27, CSR27 x CSR2, CSR27 x CSR50, CSR50 x CSR27, CSR2 x CSR50 and CSR50 x CSR2 along with CSR2 pure breed were assessed for performance of parental crop,grainage, rearing and reeling performance. The foundation crosses exhibited better performance than CSR2 as a parental crop and male component which resulted in higher egg recovery. Though there was not much difference between PM crossed with FC2 and CSR2 males pertaining to important bioassay parameters, PM x CSR2 exhibited superiority in reeling traits particularly with reelability and raw silk %. This study reveals that FC2 seed cocoons can be utilized during exigency when there is a dearth for CSR2 seed cocoons but not regularly.

A Least Squares Regression Model to Detect Quantitative Trait Loci with Polar Overdominance in a Cross of Outbred Breeds: Simulation

  • Kim, Jong-Joo;Dekkers, Jack C.M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.11
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    • pp.1536-1544
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    • 2013
  • A least squares regression interval mapping model was derived to detect quantitative trait loci (QTL) with a unique mode of genomic imprinting, polar overdominance (POD), under a breed cross design model in outbred mammals. Tests to differentiate POD QTL from Mendelian, paternal or maternal expression QTL were also developed. To evaluate the power of the POD models and to determine the ability to differentiate POD from non-POD QTL, phenotypic data, marker data and a biallelic QTL were simulated on 512 F2 offspring. When tests for Mendelian versus parent-of-origin expression were performed, most POD QTL were classified as partially imprinted QTL. The application of the series of POD tests showed that more than 90% and 80% of medium and small POD QTL were declared as POD type. However, when breed-origin alleles were segregating in the grand parental breeds, the proportion of declared POD QTL decreased, which was more pronounced in a mating design with a small number of parents ($F_0$ and $F_1$). Non-POD QTL, i.e. with Mendelian or parent-of-origin expression (complete imprinting) inheritance, were well classified (>90%) as non-POD QTL, except for QTL with small effects and paternal or maternal expression in the design with a small number of parents, for which spurious POD QTL were declared.

Possibility of breeding super rice cultivars using gene linkage

  • Tran, Dang Xuan;Tran, Dang Khanh;Truong, Thi Tu Anh
    • Proceedings of the Korean Society of Crop Science Conference
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    • pp.27-27
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    • 2017
  • The rapid growth of world population, reduction of cultivated areas for crop production, and detrimental effects of pests, diseases, and climate changes have required to breed new rice cultivars with high yield, accepted quality, but strong resistance to abiotic and biotic stresses. However, traditional breeding needs much time to breed a new cultivar, whereas the successful use of molecular breeding is still questionable. We have developed a novel mutation which allow to cross many rice cultivars together with low segregation, that allow to breed a new cultivar in only several cropping. The mechanism has been unknown, but we suggest that gene linkage may play a crucial role, of which the semi dwarf gene might be the center gene for gene linkage occurrence. The phenomenon of this possible gene linkage is contrary to Mendel rules, but it is promising to breed new rice cultivars, of which, the most elite genes in rice might be able to gather in a targeted rice variety.

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Seroprevalence of specific Brucella infection of cattle in Bangladesh Agricultural University Veterinary Clinics and its surrounding areas

  • Rahman, Md. Siddiqur;Alam, Nur;Rahman, A.K.M. Anisur;Huque, A.K.M. Fazlul;Ahasan, Md. Shamim;Song, Hee-Jong
    • Korean Journal of Veterinary Service
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    • v.32 no.3
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    • pp.219-225
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    • 2009
  • A cross sectional survey was conducted to determine the seroprevalence of brucellosis in cattle in Bangladesh Agricultural University (BAU) Veterinary Clinics, in BAU Dairy Farm and Vabokhali from June 2008 to November 2008. A total of 200 serum samples were collected from BAU Veterinary Clinic, from BAU Dairy Farm and Vabokhali. Among the serum samples 143 sera samples were collected from BAU Veterinary Clinic, 42 serum samples from BAU Dairy Farm and 15 serum samples from Vabokhali. Sera were separated from blood samples and tested with specific Brucella abortus antigen (BAA) test and B. melitensis antigen (BMA) test. The overall seroprevalence of brucellosis in cattle was 5% in BAA and 0.5% in BMA. It was observed that, a significant higher prevalence of B. abortus was found in female than male. An insignificant higher prevalence of brucellosis was found in adult cattle (aged above 5 years), in cross breed cattle, in cattle with grazing, cattle breed by natural breeding, and in pregnant cows. Although insignificant but a higher prevalence of brucellosis was found in aged cattle than young cattle, cross bred cattle, pregnant cattle than non pregnant cattle, cattle with grazing. A higher prevalence of brucellosis was found in female cattle than male.

Effect of Antibiotic (Norfloxacin) Administration on Commercial Characters of New Bivoltine and Cross Breed Hybrid Silkworm (Bombyx mori L)

  • Rahmathulla, V.K.;Nayak, Padmanav;Vindya, G.S.;Himantharaj, M.T.;Rajan, R.K.
    • International Journal of Industrial Entomology
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    • v.7 no.2
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    • pp.191-195
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    • 2003
  • The impact of antibiotic (Norfloxacin) administration ,at different concentration (50 ppm and 100 ppm) on commercial characters of bivoltine $({CSR_2}{\times}{CR_4})$ and the cross breed race $({BL_67}{\times}{CSR_101})$ was studied. The result indicated that antibiotic administration with different concentrations significantly improved the rearing and cocoon parameters like larval duration, larval weight, growth index, single cocoon weight, single shell weight and shell ratio. The post cocoon parameters like average filament length, non-breakable filament length, raw silk percentage, raw silk recovery percentage, denier, reelability and neatness were recorded significantly higher in antibiotic treated batches. The better performances of these parameters were recorded with the increase of antibiotic concentration.

Development of Resistance to Bombyx mori Densonucleosis Virus into a Susceptible Silkworm Breed

  • Singh, G.P.;Xu, Mengkui;Chen, Yuyin;Datta, R.K.
    • International Journal of Industrial Entomology
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    • v.6 no.2
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    • pp.145-149
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    • 2003
  • Seeing inadequate disinfection and unhygenic condition in rearing area, use of disease resistant silkworm variety is the best option. In order to this, an attempt has been made to develop the resistance to Bombyx mori densonucleosis virus (BmDNV-2) into a susceptible silkworm breed Zhenon1 by cross breeding with a resistant silkworm breed SU12 and exposing the subsequent generations to BmDNV-2 followed by the selection of individuals from the surviving batches. After seven generation the evolved DNV-2 resistant strain showed the significantly higher resistance to BmDNV-2 than control Zhenon1. The economic characters of both of the breeds were almost on par.

Analysis of Environmental Effect on Reproductive Trait(Litter Size at Birth and Weaning Rate) in Swine (국내 돼지의 번식 형질(산자수 및 이유율)에 대한 환경효과 분석)

  • Choi, Tae-Jeong;Kwak, Chun-Uk;Song, Kyu-Bong;Na, Jong-Sam;Choe, Ho-Sung
    • Reproductive and Developmental Biology
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    • v.34 no.1
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    • pp.27-32
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    • 2010
  • This study was conducted to estimate the effect of the breed, sire-breeds, farrowing year, farrowing season and parity on number of born alive (NBA), number of weaning (NW) and survival rates of weaning (SRW) in swine. The data were obtained from 46,704 litters of the Landrace, Yorkshire, Duroc and Cross breed farrowed from 1996 to 2005 at 142 GP are registered in Korean Animal Improvement Association (KAIA). There was highly significant effect of breed, sire breed, farrowing year, farrowing season and parity on NBA, NW, SRW (p<0.01). The result of this study could be available to genetic improvement of reproductive traits as a basic reference in Korean pig industry. To achieve the more effective improvement of reproductive traits, additional research such as genetic parameter evaluation should be performed.

Mapping of Quantitative Trait Loci Affecting Growth Traits in a Japanese Native Chicken Cross

  • Rikimaru, K.;Sasaki, O.;Koizumi, N.;Komatsu, M.;Suzuki, K.;Takahashi, Hideaki
    • Asian-Australasian Journal of Animal Sciences
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    • v.24 no.10
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    • pp.1329-1334
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    • 2011
  • The Hinai-dori is a breed of chicken native to Akita Prefecture, Japan. An $F_2$ resource population produced by crossing low- and high-growth lines of the Hinai-dori breed was analyzed to detect quantitative trait loci (QTL) for growth traits. Highly significant QTLs for body weight at 10 and 14 weeks of age and average daily gain between 4 and 10 weeks and between 10 and 14 weeks of age were accordingly mapped in a common region between ADL0198 and ABR0287 on chromosome 1 and between MCW0240 and ABR0622 on chromosome 4, respectively. A significant QTL for body weight at 4 weeks of age and a significant QTL for average daily gain between 0 and 4 weeks of age were mapped for the first time to the same region flanking ABR0204 and ABR0284 on chromosome 1. These QTLs are good candidates for application in the development of marker-assisted selection strategies for increasing growth efficiencies in the Hinai-dori breed and native breeds of chickens in Asia.