• Title, Summary, Keyword: genetic

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Genetic Gain and Diversity in a Clonal Seed Orchard of Pinus Koraiensis Under Various Thinning Intensities (잣나무 클론 채종원에서 간벌 강도에 따른 개량효과와 유전다양성)

  • Oh, C.Y.;Han, S.U.;Kim, C.S.;Kang, K.S.;Lee, B.S.
    • Korean Journal of Breeding Science
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    • v.40 no.3
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    • pp.263-268
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    • 2008
  • Estimates of genetic gain (in volume growth) and diversity (expressed as status number, $N_s$) were determined in a clonal seed orchard of Pinus koraiensis. The genetic thinning was based on clonal breeding values (represented by general combining ability) obtained from progeny tests, clonal fertility estimated by strobilus production, and clonal size variation determined by the ramet numbers per clone. Parental GCA values for volume growth were calculated, based on height and diameter at breast height measured from field trials. Clonal fertility was estimated from the assessments of strobilus production over twelve years from 1991 to 2003, and used for the calculation of status number. There are 179 clones and 5,268 ramets in 12ha area of P. koraiensis clonal seed orchard. Genetic gain and diversity estimates were determined under assumptions of 30% pollen contamination and inferior genetic value of contaminating pollen. Genetic gain increased as thinning rates were set from 10% to 60%. However, for the higher thinning intensities, the increase of genetic gain was not remarkable. Genetic thinning by means of truncation selection resulted in a greater genetic gain but a large decrease in status number. Status number was represented around 40 clones for 10% through 60% thinning intensities, but for the higher thinning intensities, it was a bit fluctuated. Based on the present results, it could be concluded that thinning rate should not be stronger than 60% to optimize genetic gain while conserving genetic diversity. Consequently 50% or 60% thinning rate might be appropriate for genetic thinning in the clonal seed orchard of P. koraiensis. The effect of pollen contamination on the genetic gain and the consequence of genetic thinning for seed production in the clonal seed orchard, and seed orchard management scheme were also discussed.

A study on historico-genetic principle of teaching and learning in mathematics (역사발생적 수학 학습-지도 원리에 관한 연구)

  • 우정호;민세영
    • Journal of Educational Research in Mathematics
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    • v.12 no.3
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    • pp.409-424
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    • 2002
  • The historico-genetic principle has been advocated continuously, as an alternative one to the traditional deductive method of teaching and learning mathematics, by Clairaut, Cajori, Smith, Klein, Poincar$\'{e}$, La Cour, Branford, Toeplitz, etc. since 18C. And recently we could find various studies in relation to the historico-genetic principle. Lakatos', Freudenthal's, and Brousseau's are representative in them. But they are different from the previous historico- genetic principle in many aspects. In this study, the previous historico- genetic principle is called as classical historico- genetic principle and the other one as modern historico-genetic principle. This study shows that the differences between them arise from the historical views of mathematics and the development of the theories of mathematics education. Dewey thinks that education is a constant reconstruction of experience. This study shows the historico-genetic principle could us embody the Dewey's psycological method. Bruner's discipline-centered curriculum based on Piaget's genetic epistemology insists on teaching mathematics in the reverse order of historical genesis. This study shows the real understaning the structure of knowledge could not neglect the connection with histogenesis of them. This study shows the historico-genetic principle could help us realize Bruner's point of view on the teaching of the structure of mathematical knowledge. In this study, on the basis of the examination of the development of the historico-genetic principle, we try to stipulate the principle more clearly, and we also try to present teaching unit for the logarithm according to the historico- genetic principle.

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Prenatal Genetic Test (산전 유전자 검사)

  • Han, You-Jung;Ryu, Hyun-Mee
    • Journal of Genetic Medicine
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    • v.8 no.2
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    • pp.100-104
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    • 2011
  • Genetic testing has been generalized for the diagnosis of diseases and is an important method of research with advances in the life sciences. In particular, we should give better attention to the genetic test for a fetus. Because the fetus has no autonomy, ethical and social issues can arise. Therefore, appropriate genetic counseling is needed for parents to be informed with the characteristics, natural progress, and possible treatment of a genetic disease, prior to the prenatal genetic test. Physicians should also inform parents how a particular genetic risk factor relates with the likelihood of a disease, in order to assist the parents in making the best decision. Furthermore, the current law for prenatal genetic testing should be approached rationally.

Alteration of Genetic Make-up in Karnal Bunt Pathogen (Tilletia indica) of Wheat in Presence of Host Determinants

  • Gupta, Atul K.;Seneviratne, J.M.;Bala, Ritu;Jaiswal, J.P.;Kumar, Anil
    • The Plant Pathology Journal
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    • v.31 no.2
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    • pp.97-107
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    • 2015
  • Alteration of genetic make-up of the isolates and mono-sporidial strains of Tilletia indica causing Karnal bunt (KB) disease in wheat was analyzed using DNA markers and SDS-PAGE. The generation of new variation with different growth characteristics is not a generalized feature and is not only dependant on the original genetic make up of the base isolate/monosporidial strains but also on interaction with host. Host determinant(s) plays a significant role in the generation of variability and the effect is much pronounced in monosporidial strains with narrow genetic base as compared to broad genetic base. The most plausible explanation of genetic variation in presence of host determinant(s) are the recombination of genetic material from two different mycelial/sporidia through sexual mating as well as through parasexual means. The morphological and development dependent variability further suggests that the variation in T. indica strains predominantly derived through the genetic rearrangements.

Estimates of Genetic Parameters and Genetic Trends for Production Traits of Inner Mongolian White Cashmere Goat

  • Bai, Junyan;Zhang, Qin;Li, Jinquan;Dao, Er-Ji;Jia, Xiaoping
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.1
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    • pp.13-18
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    • 2006
  • Two different animal models, which differ in whether or not taking maternal genetic effect into account, for estimating genetic parameters of cashmere weight, live body weight, cashmere thickness, staple length, fiber diameter, and fiber length in Inner Mongolia White Cashmere Goat were compared via likelihood ratio test. The results indicate that maternal genetic effect has significant influence on live body weight and cashmere thickness, but no significant influence on the other traits. Using models suitable for each trait, both genetic parameters and trends were analyzed with the MTDFREML program. Heritability estimates from single trait models for cashmere weight, live body weight, cashmere thickness, staple length, fiber diameter and fiber length were found to be 0.30, 0.07, 0.21, 0.29, 0.28 and 0.21, respectively. Genetic correlation estimates from two-trait models between live body weight and all other traits (-0.06~0.07) was negligible, as were those between fiber diameter and all other traits (-0.01~0.03) except cashmere thickness (0.19). Cashmere weight and staple length had moderate to low genetic correlations with other traits (-0.24~0.39 and -0.24~0.34, respectively) except for live body weight and fiber diameter. Cashmere thickness had a strong genetic correlation with fiber length (0.81), and low genetic correlation with other traits (0.19~0.34) except live body weight. Genetic trend analysis suggests that selection for cashmere weight was very effective, which has led to the slow genetic progress of cashmere thickness and fiber length due to their genetic correlations with cashmere weight. The selection for live body weight was not effective, which was consistent with its low inheritability.