• 제목/요약/키워드: Genetic Diversity Loss

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최소좁은세상 셀룰러 유전알고리즘 (Smallest-Small-World Cellular Genetic Algorithms)

  • 강태원
    • 한국정보과학회논문지:소프트웨어및응용
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    • 제34권11호
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    • pp.971-983
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    • 2007
  • 셀룰러 유전알고리즘(CGAs)은 모집단이 특정한 위상 구조를 갖는 유전알고리즘의 일종이다. 보통의 경우, CGAs의 모집단 공간은 네트워크 이론 측면에서 상대적으로 긴 평균경로길이와 큰 클러스터링계수를 갖는 정규 격자형 위상 구조이다. 평균경로길이가 길면 멀리 떨어진 개체들 사이의 유전적 상호작용이 느리게 일어난다. 따라서 클러스터링계수를 유지하면서 평균경로길이를 줄인다면 개체의 다양성이 유지되면서도 모집단이 보다 빠르게 수렴할 것이다. 이 논문에서는 최소좁은세상 셀룰러 유전알고리즘(SSWCGAs)을 제안한다. SSWCGAs에서 각 개체는 클러스터링이 잘되었으면서도 노드를 연결하는 평균경로길이가 짧은 모집단에 거주하여, 클러스터링에 의한 세부탐색 능력을 유지하면서도 전역탐색을 잘하게 된다. 네 가지 실변수 함수와 두 가지 GA-hard 문제에 대한 실험을 통하여 SSWCGAs가 SGAs 및 CGAs보다 효과적임을 보였다.

Determination of Genetic Diversity among Korean Hanwoo Cattle Based on Physical Characteristics

  • Choi, T.J.;Lee, S.S.;Yoon, D.H.;Kang, H.S.;Kim, C.D.;Hwang, I.H.;Kim, C.Y.;Jin, X.;Yang, C.G.;Seo, K.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권9호
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    • pp.1205-1215
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    • 2012
  • This study was conducted to establish genetic criteria for phenotypic characteristics of Hanwoo cattle based on allele frequencies and genetic variance analysis using microsatellite markers. Analysis of the genetic diversity among 399 Hanwoo cattle classified according to nose pigmentation and coat color was carried out using 22 microsatellite markers. The results revealed that the INRA035 locus was associated with the highest $F_{is}$ (0.536). Given that the $F_{is}$ value for the Hanwoo INRA035 population ranged from 0.533 (white) to 1.000 (white spotted), this finding was consistent with the loci being fixed in Hanwoo cattle. Expected heterozygosities of the Hanwoo groups classified by coat colors and degree of nose pigmentation ranged from $0.689{\pm}0.023$ (Holstein) to $0.743{\pm}0.021$ (nose pigmentation level of d). Normal Hanwoo and animals with a mixed white coat showed the closest relationship because the lowest $D_A$ value was observed between these groups. However, a pair-wise differentiation test of $F_{st}$ showed no significant difference among the Hanwoo groups classified by coat color and degree of nose pigmentation (p<0.01). Moreover, results of the neighbor-joining tree based on a $D_A$ genetic distance matrix within 399 Hanwoo individuals and principal component analyses confirmed that different groups of cattle with mixed coat color and nose pigmentation formed other specific groups representing Hanwoo genetic and phenotypic characteristics. The results of this study support a relaxation of policies regulating bull selection or animal registration in an effort to minimize financial loss, and could provide basic information that can be used for establishing criteria to classify Hanwoo phenotypes.

The Causes of Deforestation and Loss of Genetic Resources in Bangladesh

  • Islam, Mohammad Saiful;Islam, Mohammad Jahidul;Ahmed, Sheikh Ali;Chun, Su-Kyoung;Chong, Song-Ho;Kim, Jong-In
    • 한국가구학회지
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    • 제18권4호
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    • pp.317-323
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    • 2007
  • Almost all the people, particularly the rural people are directly dependent on the continued productivity of natural resources, like water, soils, forests and fisheries. But the overuse by the extremely high population pressures has degraded the natural resources into severe widespread deforestation. The degradation of natural resources, particularly the plant resources has been a great concern for socio-economic and sustainable development of the country. The Forests in Bangladesh have been depleted and degraded in volume, area, and quantity, thus requiring urgent forest protection by identifying the causes of forest loss. There are so many causes of deforestation and loss of genetic resources such as; the timber industry, which, legal or not, are cutting too many trees; indigenous forest dwellers, having their own types of problems; migrants, who, because of problems in their places of origin, have decided to move to the forests and the government through its Forest Department which is not able or willing to implement suitable policies to regulate the cutting trees and to prevent illegal cutting. Because it is a time consuming task to mitigate the first and second sets of factors, we recommend involving forest dwellers in forestry practices as much as possible and taking necessary steps to alleviate the third and fourth sets and thereby reduce the rate of forest depletion. Accordingly, a number of strategies that should be adopted to halt the loss of remaining forest cover are discussed.

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한국의 산양(우제목, 소과)의 미토콘드리아 Cytochrome b 염기서열 다양성 (Sequence Diversity of Mitochondrial Cytochrome b Gene in Grey Goral Naemorhedus caudatus(Artiodactyla, Bovidae) from Korea)

  • Koh, Hung-Sun;Yang, Byong-Guk;Lee, Bae-Kun;Lee, Jong-Hyong
    • Animal Systematics, Evolution and Diversity
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    • 제18권1호
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    • pp.13-21
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    • 2002
  • 한국의 산양 (Naemorhedus caudatus)의 유전정보를 종보전에 활용하기 위하여, 한국의 2개 장소에서 채집한 6마리의 미토콘드리아 cytochrome b 유전자 염기서열(606 bp)의 양상을 조사하였다 상응하는 중국의 산양의 염기서열은 GenBank에서 얻어서 이용하였다. 한국의 산양의 4개 haplotype의 각각과 중국의 산양의 한 haplotype간의 nucleotide Tamura-Nei 거리는 0.0650부터 0.0803 가지의 변이를 보였으며, 산양은 소과 내에서 높은 수준의 염기서열 다양성을 나타냈다 한국의 산양에서, 양구표본의 3개 haplotype간의 거리는 0.0151부터 0.0185로, 양구집단의 유전자 다양성이 낮은 수준으로 감소되었음을 보여준다. 또한 양구의 3개 haplotype의 각각과 삼척의 한 haplotype간의 거리는 0.0343에서 0.0479였다. 지리적 거리의 멀어짐에 따르는 유전자 거리의 증가가 서식처 단절에 의해 야기되었다고 판단됨으로, 한국의 산양의 유전자 다양성의 감소를 막기 위한 여러 가지 보전 대책이 즉각적으로 수행되어야 할 것이다 산양의 분류학적 검토를 위하여 GenBank에 있는 히말라야산양 (N. goral)의 염기서열 (276 bp)도 이용하였으며, 산양은 히말라야산양과 뚜렷한 차이가 없었다. 산양과 히말라야 산양은 동종으로 판단할 수가 있지만, 두 종의 보다 많은 표본을 이용한 후속 연구가 필요하다

An Analysis of Genetic Variation and Divergence on Silk Fibre Characteristics of Multivoltine Silkworm (Bombyx mori L.) Genotypes

  • Kumaresan P.;Koundinya P. R.;Hiremath S. A.;Sinha R. K.
    • International Journal of Industrial Entomology and Biomaterials
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    • 제14권1호
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    • pp.23-32
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    • 2007
  • The nature of genetic variation and diversity among the 65 multivoltine silkworm genotypes was evaluated for 16 post cocoon characters. The components of genetic variation revealed higher PCV (60.487%) and GCV (44.56%) for evenness (variation 1) followed by cohesion (PCV=55.38%, GCV=40.36%) and non-broken filament length (PCV=32.05%, GCV=31.28%). The higher heritability ($h^2$ in broad sense) was observed for boil-off loss (95.6%) followed by non-broken filament length (95.22%). The both genotypic and phenotypic correlation indicated significant positive correlation of filament length with non-broken filament length, silk recovery, raw silk, neatness, and low neatness; and negative correlation with denier, renditta and silk waste. The principal component analysis (PCA) revealed 75.381 % of total variance from the five principal components extracted. On the basis of Mahalonobis' $D^2$ values (Ward's minimum variance), the sixty-five multivoltine silkworm genotypes were classified in to 9 clusters with substantial inter and intra cluster distances. Number of genotypes included in different clusters varied from 3 to 17. The results indicated that the optimum distance obtained in cluster VII (15.059) along with higher cluster mean values especially for filament length, non broken filament length, renditta, silk recovery, silk waste, and raw silk emphasized the utilization of these genotypes in the conventional silkworm breeding programme for improvement of multivoltine silk fibre quality. The possibility of exploiting genetic variation in post cocoon traits for efficient breeding programme is discussed.

Evolutionary Analyses of SSII-1 Gene Provides Insight into Its Domestication Signatures in Collected Rice Accessions

  • Thant Zin Maung;Yong-Jin Park
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2022년도 추계학술대회
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    • pp.215-215
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    • 2022
  • Starch synthase proteins (SSI, SSII and SSIII) in rice are mainly involved in amylopectin synthesis mediating its chain elongation, and the functional loss of SSII can increase amylose accumulation through decreasing of amylopectin chain proportions. For purposes of identifying functional haplotypes and evolutionary analyses of this gene, SSII-1, we investigated 374 rice accessions belonging to different subgroups of origins. We subsequently performed bioinformatic analyses on their variations through haplotyping, resequencing and structuring based on different classified populations. Haplotyping of cultivated rice accessions using genetic variations within SSII-1 genomic region of chromosome 10 revealed a total of 8 haplotypes, representing 6 functional haplotypes by 4 non-synonymous SNPs of three different exons (1, 4 and 10), which effect on protein structure. Higher nucleotide diversity value was found in wild group (0.0055) compared to any of cultivated subpopulations, of which aus showed the most reduction of diversity value (0.0003). Tajima's D analysis exhibits the most Tajima's D value only in admixture group (0.3600) which appears to be the cause of a sudden population contraction by rare alleles scarcity. A clear separation of some wild accessions from the admixed cultivated subpopulations was observed in PCA and phylogenetic analysis. Similar admixed pattern of population structure was estimated with an increased K values of 2 to 8 where genetic components of almost all cultivated subpopulations were shared with the wild which can also be subsequently estimated by very low FST-values by -0.011 (wild-aromatic) and -0.003 (wild-admixture).

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Phylogeography and Population Genetic Structure of Amur Grayling Thymallus grubii in the Amur Basin

  • Ma, Bo;Lui, Tingting;Zhang, Ying;Chen, Jinping
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권7호
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    • pp.935-944
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    • 2012
  • Amur grayling, Thymallus grubii, is an important economic cold freshwater fish originally found in the Amur basin. Currently, suffering from loss of habitat and shrinking population size, T. grubii is restricted to the mountain river branches of the Amur basin. In order to assess the genetic diversity, population genetic structure and infer the evolutionary history within the species, we analysised the whole mitochondrial DNA control region (CR) of 95 individuals from 10 rivers in China, as well as 12 individuals from Ingoda/Onon and Bureya River throughout its distribution area. A total of 64 variable sites were observed and 45 haplotypes were identified excluding sites with gaps/missing data. Phylogenetic analysis was able to confidently predict two subclade topologies well supported by maximum-parsimony and Bayesian methods. However, basal branching patterns cannot be unambiguously estimated. Haplotypes from the mitochondrial clades displayed local homogeneity, implying a strong population structure within T. grubii. Analysis of molecular variance detected significant differences among the different geographical rivers, suggesting that T. grubii in each river should be managed and conserved separately.

Intergenerics Nuclear Transfer Technology for Conservation of Endangered Species

  • Lee, B.C.;S.K. Kang;J.K. Cho;B. Bavister;W.S. Hwang
    • 한국수정란이식학회:학술대회논문집
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    • 한국수정란이식학회 2002년도 국제심포지엄
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    • pp.56-62
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    • 2002
  • The International Union for Conservation of Nature and Natural Resources (IUCN) considers the western/lowland bongo Tragelaphus eurycerus eurycerus to be a threatened species, and the eastern/mountain bongo Tragelaphus eurycerus isaaci an endangered species[1]. Although extinction is considered by many biologists to be a natural process during evolution, the exponential growth of the human population has drastically and prematurely reduced the numbers and genetic diversity of many species[2]. Species have evolved to adapt to a specific habitat or environment that meet their survival needs. Alteration or destruction of their habitat results in a species becoming incapable of adapting and hence becoming threatened with extinction. A widespread scientific and public consensus has emerged suggesting that governments should assign high priority to the maintenance of biological diversity via habitat preservation and management far species conservation[3]. Unfortunately, the loss of biological diversity far surpasses the available conservation resources and species are lost forever on a daily basis[4]. Notwithstanding the focus on habitat preservation and wildlife management, conservation biologists have also become increasingly interested in using the technologies of reproductive and developmental biology to help manage or rescue endangered species[5].

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분자마커를 활용한 옥수수 육종 (Genetic Improvement of Maize by Marker-Assisted Breeding)

  • 김재윤;문준철;백성범;권영업;송기태;이병무
    • 한국작물학회지
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    • 제59권2호
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    • pp.109-127
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    • 2014
  • Maize is one of the most important food and feed crops in the world including Southeast Asia. In spite of numberous efforts with conventional breeding, the maize productions remain low and the loss of yields by drought and downy mildew are still severe in Asia. Genetic improvement of maize has been performed with molecular marker and genetic engineering. Because maize is one of the most widely studied crop for its own genome and has tremendous diversity and variant, maize is considered as a forefront crop in development and estimation of molecular markers for agricultural useful trait in genetics and breeding. Using QTL (Quantitative Trait Loci) and MAS (Marker Assisted Breeding), molecular breeders are able to accelerate the development of drought tolerance or downy mildew resistance maize genotype. The present paper overviews QTL/MAS approaches towards improvement of maize production against drought and downy mildew. We also discuss here the trends and importance of molecular marker and mapping population in maize breeding.

식물 RNA 바이러스의 진화와 병저항성 극복 기작 (Evolution of Plant RNA Viruses and Mechanisms in Overcoming Plant Resistance)

  • 김명휘;권선정;서장균
    • 식물병연구
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    • 제27권4호
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    • pp.137-148
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    • 2021
  • 식물 RNA 바이러스는 전세계적으로 작물 생산량에 큰 손실을 일으키는 주요 병원체 중 하나로, RNA 바이러스가 갖는 특징인 짧은 복제 주기, 게놈 복제 중의 높은 변이 발생률 등으로 인해 높은 유전적 다양성과 적응성을 가지며 진화해 왔다. 식물 RNA 바이러스는 유전적 다양성을 갖는 유사종 군집으로 존재하며, 환경 변화에 따른 선택압으로 새로운 적합성을 갖는 군집으로의 변천이 빠르게 일어날 수 있다. 식물의 저항성은 일종의 선택압으로 작용하여 바이러스의 적합성에 영향을 미치며, 이는 기주의 저항성을 극복하는 변이 바이러스의 출현으로 이어질 수 있다. 본 논문에서는 식물 RNA 바이러스에 대한 진화적 관점 및 진화의 원동력을 소개하고, 이를 바탕으로 식물 저항성을 극복하는 변이 바이러스의 출현 기작을 다루고자 한다. 또한 바이러스병에 대한 저항성 전개 및 내구성 향상을 위한 전략에 대해 논하였다.