DNA Fingerprinting for Identification of Plant Species

deoxyribonucleic acid Fingerprinting for Identification of Plant SpeciesABSTRACTConservation of congeal resources prevents the loss of expensive put species in the past centuries. Many species alike that of wild Panax ginseng, Panax quinquefolius , Japonica ar menace and requires restoration. Its unseemly impact on environmental and socioeconomic surveys has triggered the studies on de margeine transformation. It is seen that subdue identification and characterization of determine materials is essential for the preservation of fructify resources and to realise their sustainable use. Molecular tools developed in the past fewer years provide easy, less laborious means for assigning know and un cognise plant taxa. These proficiencys answer umpteen new developmentary and taxonomic questions, which were not previously possible with only phenotypic systems. Various techniques such(prenominal)(prenominal) as desoxyribonucleic acid bar coding, random amplified polymorphic deoxyribonucleic acid (RAPD), microsatellites, amplified segment length polymorphism (AFLP) and single nucleotide polymorphisms (SNP) have recently been utilize for plant variety studies. Sequencing base molecular techniques provide let on closure at intra-genus. Whereas information from markers such as random amplified polymorphic deoxyribonucleic acid (RAPD), amplified fragment length polymorphism (AFLP) and microsatellites provide the means to classify some nonp areil medicine. In addition desoxyribonucleic acid methods atomic itemize 18 reliable approaches towards authentication of Chinese medicinal materials. For future reference, it is necessary to compile library of Chinese medicines which entangle patrimonial cultivation, especially for endangered species and those with in luxuriously spirits market value and or with possible poisonous adulterants which jakes affect quality of medicine.INTRODUCTIONFor the sustainable development and for improvement and maintenance of agricultural and forestry production there is a use for preservation of plant ingredienttic resources. The objective of plant comp unmatchednttic resources conservation is to preserve as broad a sample of the existent patrimonial mixture of target species as is scientifically and economically feasible, including soon recognized divisors, traits and genotypes 1. Genetic renewing finds its immanent resources in wild species for which it is primary(prenominal) to find turn out the amount of transmittable variability by the focussing of morphological, biochemical and molecular markers, besides some vexing physiological turns. portraiture of conversion is based on morphological traits. However, it is seen that morphological variability is denouncely restricted, characters may not be obvious at all stages of the plant development. Identification plays a very important role in diversity studies. Accurate classification of individuals is essential for evalu ation of species diversity. The identification of taxonomic units and endangered species, whose heritable constitution is distinct from their to a greater extent abundant relatives, is important in the development of appropriate conservation strategiesNowadays, a variety of different patrimonial markers has been proposed to assess genetic variability. Molecular tools provide valuable selective information on diversity through their ability to detect variation at the desoxyribonucleic acid levelCONSERVATION OF PLANT GENETIC RESOURCESEffective conservation of plant genetic resources requires a full complementary approach which makes use of both(prenominal) ex situ and in situ conservation methods to maximize the genetic diversity lendable for use.ex situ conservationThe objective of ex situ conservation is to maintain the portals without change in their genetic constitution 1. The methods that be designed argon such that put up of tail be utilize to minimize the possibility o f mutation, random genetic drift, natural selection or contamination. It is seen that storing of seeds at low temperatures and humidities crapper bring long term ex situ conservation. But there be many clonally propagated species, such as banana and potato, fag endnot be conserved in this way, and many species, incidently tropic forest tree species, produce seeds that are recalcitrant and cannot be stored. These species can only be maintained ex situ in field gene lingos as growing sights of plants, or in vitro using tissue culture or cryopreservation 2.In situ conservationIn situ conservation is considered to be the method of choice for conserving forest species and wild crop relatives and there is increasing interest in the use of in situ conservation for crops themselves (on-farm conservation) 3. In situ conservation allows evolution to continue, increases the amount of diversity that can be conserved, and strengthens links amid conservation workers and the communities who have traditionally maintained and used the resources.All genetic resources conservation activities require characterization of the diversity present in both the gene pools and the gene banks. Molecular genetics has an important role to play in many aspects of conservation such as characterizing plant genetic diversity for purposes of improved acquisition, maintenance and use. A number of different techniques are functional for identifying genetic going aways between organisms. The choice of technique for any one particular(prenominal) use will depend upon the material being studied and the personality of the questions being addressed. Protein polymorphisms were the first markers used for genetic studies. However, the number of polymorphic loci that can be assayed, and the level of polymorphisms observed at the loci are oft low, which greatly limits their application in genetic diversity studies. With the development of new technologies, desoxyribonucleic acid polymorphisms have become the markers of choice for molecularbased surveys of genetic variation. deoxyribonucleic acid markers are useful in both basic (e.g. phylogenetic summary and search for useful genes) and applied research (e.g. marker assisted selection, paternity testing and food traceability). A number of markers are now available to detect polymorphisms in nuclear deoxyribonucleic acid 4. Properties desirable for ideal deoxyribonucleic acid markers acknowledge highly polymorphic nature, co dominant, frequent occurrence in the genome, selective neutral behavior, easy access, easy and fast assay and high reproducibility 5.NEED FOR GENETIC RESOLUIONIt is a duty of Gene bank managers and conservationists c at one timerned with both in situ and ex situ care to conserve as much as possible the extinct genetic diversity of the species with which they work. The authority with which they do this depends to a large extent on the genetic information available on the germplasm with which th ey work. Molecular markers provide genetic information of channel value in key areas of conservation both ex situ and in situ.For ex situ conservation the key issues areAcquisition Data on the diversity of existing collections can be used to plan collection and exchange strategies. In particular, calculations of genetic distances based on molecular data can be used to identify particular divergent subpopulations that mightiness harbour valuable genetic variation that is under-represented in current holdings alimentation Genetic data are essential to identify duplicate accessions in order to ensure best use of available resources. Genetic markers are in any case needed to monitor changes in genetic bodily structure as accessions are generated. Molecular markers provide markers suitable for both of these.Characterization The genetic diversity within collections must be assessed in the context of the join available genetic diversity for each species. Existing passport data documen t the geographic location where each accession was acquired. However, passport records are often missing or incorrect. Molecular markers may extend and complement characterization based on morphological or biochemical descriptions, providing much accurate and detailed information than classical phenotypic data.Distri only whenion to users Users of collections utility from genetic information that allows them to identify valuable traits and types quickly. On a more fundamental level, molecular marker information may lead to the kick upstairs identification of useful genes contained in collections. Molecular data on diversity may provide essential information to develop core collections 6 that accurately represent the entire collection.Molecular markers may therefore be used in quadruplet types of measurements needed for effective ex situ conservation, all of which are useful in resolving the numerous operational, logistical, and biological questions that face gene banks managers 7. These areidentity the intention of whether an accession or individual is catalogued correctly, is honest to type, maintained properly, and whether genetic change or erosion has occurred in an accession or population over timeSimilarity the degree of law of similarity among individuals in an accession or between accessions within a collection. complex body part the partitioning of variation among individuals, accessions, populations, and species. Genetic structure is influenced by in situ demographic factors such as population size, reproductive biology and migration.Detection the comportment of particular allele or nucleotide sequence in a taxon, gene bank accession, in situ population, individual, chromosome or cloned deoxyribonucleic acid segment.Those concerned with in situ conservation need to ensure that appropriate populations are identified and managed in such a way that they survive and continue to evolve. Their responsibilities can includeLocation the identification of populations which should be conserved based on the genetic diversity present as well as on the value of the resource and the threats to it. Crucial to this is knowledge of the extent and distribution of genetic diversity in species populations which should optimally include molecular data.Management the development of management plans to monitor the changes in target populations over time and ensure their proceed survival. The populations maintained in situ constitute part of ecosystems and both intra- and interspecific diversity must be maintained over time at appropriate levels.Accessibility in situ conservation is near usually of interest in forest genetic resources conservation and that of wild crop relatives but it is also of increasing interest for on-farm conservation of traditional cultivars. Genetic resources conserved in this way remain accessible to the communities who depend on them. Managers need to ensure they are also accessible to other users and that sufficien t genetic information is available to assist such users.Within the context of in situ conservation, therefore, identity, similarity, structure and detection are also important and can be usefully investigated using molecular techniquesBASIC GENETIC TOOLSDNA sequencingDNA sequencing is the determination of the precise sequence of nucleotides in a sample of DNA. The nucleotides bases are A (adenine), G (guanine), C (cytosine) and T (thymine)The conventional and next times sequencing techniques are thus been explained in detail.Conventional Sequencing Technique-Now days it is seen that dye-terminator sequencing technique is the exemplar method in automated sequencing analysis 8. And for majority of sequencing the dye-terminator sequencing method, along with automated high-throughput DNA sequence analyzers, is used.Dye-terminator sequencingutilizes labelling of the filament terminator dents, which permits sequencing in a single reaction, rather than four reactions as in the labelle d-primer method. In dye-terminator sequencing, each of the four di de-oxynucleotide chain terminators is labelled with fluorescent dyes, each of which emit light at different wavelengths. Owing to its greater expediency and speed, dye-terminator sequencing is now the mainstay in automated sequencing. The main advantages of this technique are its robustness, automation and high the true Its limitations include dye effects due to differences in the incorporation of the dye-labelled chain terminators into the DNA fragment, resulting in unequal peak heights and shapes in the electronic DNA sequence tracechromatogramaftercapillary electrophoresis. This puzzle has been addressed with the use of modified DNA polymerase enzyme systems and dyes that minimize incorporation variability, as well as methods for eliminating dye blobs.DNA barcoding of plants has now gained the interest of scientists with the set out to identify an unknown plant in terms of a known classification. DNA barcoding is a technique for characterizing species of organisms using a concise DNA sequence from a standard. DNA barcode sequences are thus shorter than the entire genome and can be obtained quickly 9. staple fibre Local Alignment Search animal (BLAST) was used for species-level assignment of plants and individual barcodes were obtained with matK (99%), followed by trnH-psbA(95%) and then rbcL (75%) 10. Recently, a collection of plant DNA barcode researchers proposed two chlorop dwell genes, rbcL and matK, taken together, as appropriate for bar-coding of plants 11.Chloroplast DNA (cpDNA) is the basis of Molecular phylogenies in plants but the problems due to gene lean of cpDNA among closely related taxa, as well as the lack of phylogenetic outcome, triggered the development of new approaches based on nuclear DNA 13. The most common alternative corresponds to the sequencing of the ITS (internal transcribed spacer) of 18S-25S nuclear ribosomal DNA 14, 15. The failure of both cpDNA and I TS techniques to sequence, the amplified fragment length polymorphism (AFLP) approach has the potential to solve such difficulties, particularly among closely related species, or at the intra-specific level 16-18. Therefore, integration of recently developed bar-coding with the following techniques such as RAPD, AFLP, microsatellite and SNP seems to provide better resolution.Next Generation Sequencing TechniquesNext generation platforms do not bank on Sanger chemistry 19 as did the first generation machines used for the last 30 years. The first of this kind of 2nd generation of sequencing technique appeared in 2005 that was based on pyrosequencing 20, 21 Commercial 2nd generation sequencing methods can be distinguished by the role of PCR in library preparation. There are four main platforms all being working out-based (i) Roche 454 GS FLX, (ii) Illumina Genome Analyzer IIx, (iii) ABI SOLiD 3 Plus System and (iv) Polonator G.007 22 The single- element sequencing method (also known as 3rd generation or next-next generation) is independent of PCR 25,30. This mode of sequencing protocol was recently developed by Helicos Genetic Analysis System using the technology developed by Braslavsky et al. 23. Other 3rd generation sequencing systems are being developed by Life Technologies and Pacific Biosciences SMRT technology and may appear within one to two years.Random Amplified Polymorphic DNA (RAPD)The invention of PCR (polymerase chain reaction) is a milestone in the development of molecular techniques. PCR results in the selective enlargement of a chosen region of a DNA molecule. Random amplification of DNA with short primer by PCR is a useful technique in phylogenetics. The important point is the wading pattern seen, when the products of PCR with random primers are electrophoresed in a reflection of the overall structure of the DNA molecule used as the template. If the starting material is total cell DNA then the banding pattern represents the organization of th e cells genome. Differences between the genomes of two organisms can be measured with RAPD. Two closely related organisms would be expect to yield more similar banding patterns than two organisms that are far-flung in evolutionary terms 24. Moreover, this technique requires only small piece of animal tissue or blood, as the extracted DNA can be amplified million times using PCR.Basic protocolEXTRACTION OF super PURE DNAADDITION OF SINGLE ARBITARY PRIMERPOLYMERASE CHAIN answer (PCR)SEPARATION OF FRAGMENTS BY GEL ELECTROPHORESISVISUALIZATION OF RAPD-PCR FRAGMENTS AFTER EtBr detection UNDER UVDETERMINATION OF FRAGMENT SIZEThis technique has in the first place gained attraction as there is no requirement for DNA probes or sequence information for primer designing. There are also no blotting or hybridizing steps. This technique only requires the purchase of a thermo cycle machine and agarose gel apparatus and relevant chemicals, which are available as commercial kits and also it is a quick and simple technique. It is important to look that RAPD technique requires maintaining strictly consistent reaction conditions in order to hand reproducible profiles 25.The RAPD markers have been used for detecting genomic variations within and between varieties of sweet-flavored potato. A total of 160 primers were tested and eight showed consistent amplified band patterns among the plants with variations within and between varieties 26 of sweet potato.Restriction fragment length polymorphismAll organisms are genotypically different because they have had numerous differences in their genomic DNA. This difference results in a restriction fragment length polymorphism. Here the chromosomal DNA is first cleaved by restriction enzymes creating fragments and then these fragments are stranded by agarose gel electrophoresis. After it southern hybridization analysis is carried out using probe that spans the region of interest. The probe hybridizes to the relevant region, lighting up the appropriate restriction fragments on the resulting autoradiograph. If an RFLP is present then it will be clearly visible on the autoradiograph. Thus RFLP is used as a major tool to identify the genetic diversity within and between species 27.Basic ProtocolCHROMOSOMAL DNACleave with Restriction enzymesDNA FRAGMENTSSEPARATE FRAGMENTS BY AGAROSE GEL ELECTROPHORESISDENATURE DNA AND enrapture TO NITROCELLULOSERadiolabelled DNAprobeINCUBATE WITH PROBEEXPOSE X-RAY FILM TO radicalAmplified fragment length polymorphismAFLP analysis is able to detect high levels of polymorphism and has high repeatability and speed of analysis. AFLP technique as being based on the detection of restriction fragments by PCR amplification and argued that the reliability of the RFLP technique is combined with the power of the PCR technique. Firstly extraction of highly purified DNA then restriction endonuclease digestion of DNA followed by ligation of adapters. After this amplification of these fragments is make by two primers, and then gel electrophoresis and analysis of fragments by automated sequencing machines.The advantage of this technique is that it is applicable to all species and unlike RAPD this technique is highly reproducible as it combines restriction digestion and PCR. However, AFLP requires more DNA (300-1000 ng per reaction) and is more technically demanding than RAPD 4.AFLP markers in surveys of plant diversity are discussed in a review published by Mba and Tohme 28. Recently, Jatropha curcas 29 and Rhodiola rosea 30 have been characterized by AFLP in germplasm collection. The wild populations of Agave angustifolia in the desert was studied by Teyer et al. 31 using AFLP to measure the genetic variability within and between natural populations. AFLP markers have been extensively used for phylogenetic analysis and determining the genetic diversity for conservation of endangered plant species 32-36. isolation OF GENOMIC DNABasic protocolDIGESTION WITH ONE OR MORE pa rapet ENZYMESLIGATION OF RESTRICTION HALF-SITE limited ADAPTORS TO ALL RESTRICTION FRAGMENTSAMPLIFICATION OF THESE FRAGMENTS WITH TWO PCR PRIMERS THAT HAVE CORRESPONDING ADAPTORS AND RESTRICTION SPECIFIC SEQUENCESELECTROPHORETIC SEPARATION OF AMPLICONS ON A GEL hyaloplasmMICROSATELLITESMicrosatellites, are alternatively known as simple sequence repeats (SSRs), short tandem bicycle repeats (STRs) or simple sequence length polymorphisms (SSLPs). These are tandem repeats of sequence units generally less than 5 bp in length 37.One common example of a microsatellite is a (CA)n repeat, where n is variable between alleles. These markers often present high levels of inter and intraspecific polymorphism, particularly when tandem repeats number ten or greater. CA nucleotide repeats are very frequent in human and other genomes, and present every few constant of gravitation base pairs. InterSSRs are a variant of the RAPD technique, although the higher temper temperatures probably mean that they are more rigorous than RAPDs.The microsatellite protocol is simple, once primers for SSRs have been designed. The first stage is a PCR, depending upon the method of detection one of the primers is fluorescently or radioactively labeled. The PCR products are separated on high resolution polyacrylamide gels, and the products detected with a fluorescence detector (e.g. automated sequencer) or an X irradiate film. The investigator can determine the size of the PCR product and thus how many times the short nucleotide was repeated for each allele.Microsatellites developed for particular species can often be applied to closely related species, but the percentage of loci that successfully amplify may decrease with increasing genetic distance 38. Microsatellite technique has recently been used to establish conservation outline of endangered plants like Calystegia soldanella 39, Tricyrtis ishiiana 40 and Galium catalinense subspecies acrispum 41.ISOLATION OF GENOMIC DNABasic protocolSEQ UENCINGDESIGNING OF PRIMERS FOR REGIONS FLANKING MICROSATELLITESELECTROPHORETIC SEPRATION OF AMPLICONS ONA GEL MATRIXISOLATION OF GENOMIC DNAConclusionMolecular characterization can play a role in uncovering the history, and estimating the diversity, distinctiveness and population structure. Awareness of the level of genetic diversity and the proper management of genetic resources are important issues in modern scenario. New markers deriving from DNA technologies are valuable tools to study genetic variability for conservation purposes. In the near future, the advent of genomics will give an impressive tool for genetic resources evaluation.