• Title/Summary/Keyword: genetic characterization

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The genetic structure of taro: a comparison of RAPD and isozyme markers

  • Sharma, Kamal;Mishra, Ajay Kumar;Misra, Raj Shekhar
    • Plant Biotechnology Reports
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    • v.2 no.3
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    • pp.191-198
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    • 2008
  • Germplasm characterization and evolutionary process in viable populations are important links between the conservation and utilization of plant genetic resources. Here, an investigation is made, based on molecular and biochemical techniques for assessing and exploiting the genetic variability in germplasm characterization of taro, which would be useful in plant breeding and ex situ conservation of taro plant genetic resources. Geographical differentiation and phylogenetic relationships of Indian taro, Colocasia esculenta (L.) Schott, were analyzed by random amplified polymorphic DNA (RAPD) and isozyme of seven enzyme systems with specific reference to the Muktakeshi accession, which has been to be proved resistant to taro leaf blight caused by P. colocasiae. The significant differentiations in Indian taro cultivars were clearly demonstrated by RAPD and isozyme analysis. RAPD markers showed higher values for genetic differentiation among taro cultivars and lower coefficient of variation than those obtained from isozymes. Genetic differentiation was evident in the taro accessions collected from different regions of India. It appears that when taro cultivation was introduced to a new area, only a small fraction of genetic variability in heterogeneous taro populations was transferred, possibly causing random differentiation among locally adapted taro populations. The selected primers will be useful for future genetic analysis and provide taro breeders with a genetic basis for selection of parents for crop improvement. Polymorphic markers identified in the DNA fingerprinting study will be useful for screening a segregating population, which is being generated in our laboratory aimed at developing a taro genetic linkage map.

Biodiversity and Conservation of Indian Sheep Genetic Resources - An Overview -

  • Bhatia, S.;Arora, R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.10
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    • pp.1387-1402
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    • 2005
  • Indian subcontinent is a rich source of diverse ovine germplasm, and only very few countries have such a large number of breeds with wide genetic diversity. This vast ovine biodiversity in India is being eroded rapidly and more than 50% of sheep breeds are currently under threat. It is noteworthy that the characterization of Indian sheep breeds was last done in the first half of the century since then no recent estimates are available and surveys in majority of the regions/breeds are far from complete. Starting in 1985 National Bureau of Animal Genetic Resources (NBAGR), Karnal, India, therefore, initiated activities aimed at determining the status and compiling information on indigenous farm animals including sheep. This report represents attempts made to date on the basis of field/literature surveys and additional activities on molecular characterization to ascertain their status including distribution, population changes, breed diversities and risk status. The need, mode and mechanisms of conservation are also described. Involvement of several agencies for evaluation, improvement, conservation programmes and recommendations made for effective characterization and conservation of sheep biodiversity are highlighted. This publication would promote action particularly at national level to improve the information base on domestic Indian breeds of sheep and provide input into national domestic sheep diversity conservation policy decisions.

Analysis of Microsatellite DNA Polymorphisms in Five China Native Cattle Breeds and Application to Population Genetics Studies

  • Jin, Hai-Guo;Zhao, Yu-Min;Zhou, Guo-li
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.12
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    • pp.1696-1700
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    • 2005
  • Five China native cattle breeds have been characterized by using 10 microsatellite DNA markers. The studied populations can be divided into five groups: Luxi cattle, Nanyang cattle, Jinnan cattle, Qinchuan cattle and Yanbian cattle. Allele frequencies were calculated and used for the characterization of the breeds and the study of their genetic relationships. Heterozygosity, polymorphism information content, the effective number of alleles was calculated. Nei' standard genetic distance (1978) was calculated and used for a neighbor-joining tree construction. NJ tree showed that Luxi cattle, Nanyang cattle, Jinnan cattle and Qinchuan cattle are closely related, whereas Yanbian cattle are clearly distinct from other four populations. The genetic relationship of five breeds corresponds to their history and geographic origins. This work analyzes the recent origin of these populations and contributes to the knowledge and genetic characterization of China native breeds.

Phylogenetic Relationships and Characterization of Korean Native Silkworm Strains Based on RAPDs and Isozyme Analysis, Bombyx mori (동위효소 및 RAPD분석에 의한 한국재래종 누에계통의 계통학적 특성)

  • 이재만;노시갑
    • Journal of Sericultural and Entomological Science
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    • v.43 no.2
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    • pp.59-66
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    • 2001
  • This study was conducted to elucidate phylogenetic relationships and genetic characterization of silkworms that might be recognized as the Korean native strains. Genetic characterization in isozymes and the proteins of larval hemolymph of 17 silkworms were observed by acrylamide gel eletrophoresis, on 12 genes; Bph, Bes, les, Amy-hc, Ict-A, -B, -D,-E,-H, Pfl, Pst, Lp. Gene frequencies in each locus were compared other geographic strains. Korean native strains were remarkably different from others considered as the genetic characterization of Korean native strains. Phylogenetic relationships in Korean native strains were analysed using RAPD-PCR markers. A total of 40 primers were used and 346 bands of amplified DNA were generated from geographic strains. Genetic similarity based on the RAPD bands was used to construct phylogenetic dendrogram based on analysis of bard sharing data of amplified markers. Genetic similarity ranged from 0.595 to 0.860. In the genetic relationship based on dendrogram, they were classified into Bombyx mori group (including 16 domesticated silkworm strains) and B. mandarina group. The Bombyx mori group was separated into three sub-groups at the genetic similarity of 0.6930, including Korean, Japanese and Chinese groups. According to this result, the Korean native variety can be considered as a clearly different variety from other geographic strains. It may be concluded that the Korean native strains are also one of original geographic variety such as Japanese, Chinese, etc.

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Conservation of Multivoltine Silkworm (Bombyx mori L.) Germplasm in India - An Overview

  • Kumaresan, P.;Sinha, R.K.;Mohan, B.;Thangavelu, K.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.9 no.1
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    • pp.1-13
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    • 2004
  • Indian multivoltine mulberry silkworm (Bombyx mori L.) strains are poor in silk productivity and fibre quality. However, they are commercially exploited for the past five decades either in the form of pure breeds or cross breeds because of their adaptability to adverse climatic condition and acclimatization to specific regions and seasons. In the present paper conservation strategies of multivoltine silkworm genetic resources are dealt along with detailed information on accessibility of genetic resources, method of genetic resources conservation, characterization of genetic resources for morphological and productivity traits of economic importance. Selection of best ten accessions based on various economic parameters including yarn quality and their scope for future utilization are discussed.