Today, bar codes by Bernard Silver, a design student at Drexel Institute of Technology in Philadelphia, PA, and his friend Norman Woodland and Jordin Johanson in 1948 for universal use. They play a crucial role for the identification, monitoring, and relational data. They are particularly useful because scanning is relatively inexpensive, highly accurate and highly efficient to obtain and transmit information from bar codes and theirDatabase.
Barcode natural (a little short of deoxyribonucleic acid (DNA) (the unique genetic code for all living organisms and some viruses), which is between 300-800 base pairs (bp) - adenine (A)-thymidine (T ) and cytosine (C), guanine (G)), which are represented by different colors) are available and are well established in the animal kingdom. With the sequencing of the cytochrome oxidase 1 (CO1) gene (inspired by the biologist Paul Hebert efforts in vainto determine the years 1970 2000 species of moths in Papua New Guinea (because of their taxonomic and morphological similarities), and his "withdrawal of water fleas" (of which there are only 200 species) and the subsequent 2003 paper in which he described "the variety life is hard as a burden" for biologists "and suggested that" all species on Earth ... a single DNA barcode is assigned, it would be easy to distinguish, "as written in the scanning of life (National Geographic, May 2010)), which in itselfmitochondrial DNA of every multicellular organism, scientists can easily determine phylogeny (identification) at the molecular level and stored in a database for easy retrieval. In PM Hollingsworth, DNA barcoding plants in biodiversity hot spots: progress and outstanding issues (inheritance, April 9, 2008), "barcode DNA is now routinely used for identification of the organism" in animals and has contributed to the discovery of new species. "
But Mark W. Chase,Nicolas Salamin, Mike Wilkinson, James M. Dunwell, Kesanakurthi Prasad Rao, Nadia Haidar, and Vincent Savolainen, terrestrial plants and DNA barcodes: short-and long-term goals (Philosophical Transactions of the Royal Society, 2005), this is not the first in crops with a maximum of recently, since their CO1 gene has the ability, genes serve as a bar code and it works for the variability in DNA barcoding "of the cause of" low "had a reputation for being difficult andThe lack of variation "plastid phylogenetic markers. This view prevailed until 2008, when a team led by Dr. Vincent Savolainen, Imperial College London's Department of Life Sciences and the Royal Botanic Gardens, Kew protein studied the functionality of megakaryocyte associated tyrosine kinase (matK) gene is located in the chloroplast trnK intron of genes found in the leaves of plants. Their research found that the matK gene (which contained "significant species-level geneticVariability and divergence of conservation of sites to accompany the development of PCR (polymerase chain reaction, a process that scientists, millions of copies of a particular DNA sequence in approximately two hours to produce, bypassing the need for bacteria allows you to amplify DNA) primer widely used for taxonomic, [and] short length of sequence ... to facilitate the ... The DNA extraction and amplification), as reported by John W. Kress and David L. Erickson DNA barcodes: the genes, genomics and bioinformatics(PNAS. Vol 105, No. 8 February 26, 2008) and the Polymerase Chain Reaction (PCR) (Gene Almanac. Dolan DNA Learning Center and Cold Spring Harbor Laboratory, Inc., 2009) was able to distinguish between at least 90 years % all plants, including those that look identical to the human eye, known as cryptic species because of their identical appearance and genetic differences.
The matK gene has been found, however, ineffective in distinguishing between up to 10% of the plantSpecies from two main factors:
1. As a variation of "bursts of rapid speciation" was small, and
2. Based on an article by Anna-Marie Lever, the 'barcode' revealed in plants DNA (BBC News, 6 February 2008) when the plants were growing hybrids, whose genome has been re-by natural and artificial cross confuse [d] matK gene information "
While noting that the matK gene can serve as natural plant barcode has been done, it was his positioncomparable to that of animals - (mitochondria used as a "little bundles of energy in animal cells, whereas the chloroplasts are involved in photosynthesis in plants), the genes of the bar code on both sites of cellular energy outside the nucleus, as Anna-Marie Lever, showed the DNA 'barcode' are in plants, nuclear genes usually develop rapidly between [the bodies] of the same type of distinction. " However, in accordance with mitochronidrial genes in animals, genes of chloroplasts [in plants] for a furtherslower, so that [distinguishment between the same species, and] to occur fast enough for differences in the DNA code between species. "
The only exception among the plants and animals is the area of effectiveness for each gene barcode. The CO1 gene can be used effectively to determine and record phylogeny in almost 100% of the species, while types matK gene ineffective for 10% of the plant. The main reason for the range with 90%As for the matK gene animals as the natural result of crossing plants that are significantly more often. For this reason, the general information should be supplemented by other data gene matK. Although studies with trnH-psbA genes with characteristics similar to matK showed promise (in the sequencing of matK and trnH-psbA was used with plants of the nutmeg family (Myristicaceae), the actual extent of the law The identification has risen to around 95%), a panel of 52 eminent scientists Barcoding has decided to use ribulose bisphosphate carboxylase (rbcL) gene (also chloroplasts is attached) science in a 2009 paper published in Proceedings of National Academy, as reported by Daniel Cressey, barcode DNA to the plant one step closer (Nature, July 27, 2009), to effectively integrate the barcode for the group of 10%.
While the discovery of phylogenetic utility of matK> Gene is relatively new, studies show the usefulness of phylogenetic gene rbcL date as far back as 1986, when Jane Aldrich, Barry Cherney, Ellis Merlin, and Jeff Palmer reported in Nucleic Acids Research, showed that the sequencing of genes of petunia rbcL and tobacco and alfalfa and peas are 97.3% and 94.1% genetically identical when comparing their bps.
Further studies, to name two, added a further demonstration of the phylogenetic utility of gene rbcL.A, sequences reported by Mitsuyasu Hasebe, Tomokyuki Omori, Miyuki Nakazawa, Toshio Sano, Masahiro Kato and Kunio Iwatsuki rbcL genes provide evidence leptosporangiate lineages of ferns (Proceedings of National Academy of Sciences, June 1994) used PCR-amplified fragments rbcL leptosporangiate in 58 species of ferns, the (reproduction produce vascular plants, the spores instead of flowers and seeds) for the class of Pteridophytes, arelongest history of all terrestrial vascular plants (hence the largest permanent loss of user data plylogentically) capture their evolutionary links. Other reports reported by Hiroaki Setoguchi, Takeshi Asakawa Osawa, Jean-Christophe Pintaudi, Jaffré Tanguy and Jean-Marie Veillon in phylogenetic within Araucariaceae on sequences of rbcL genes (American Journal of Botany, 1998) based on rbcL gene sequencing success to determine thepylogenetic relationship between 29 species of Araucariaceae (a sample of almost all existing species of ancient family of conifers, the maximum diversification of the Jurassic (about 199.6 ± 0.6 to 145.5 ± 4 million years (MA) and Cretaceous (c. 4 and reached 145.5 ± 65.5 ± 0.3 mA)).
Although the study shows that the gene has led to the discovery that the matK gene tree might be a bar code as a primary, Dr Savolainen team of eight potentialThe candidate genes and analyzed more than 1,600 DNA samples from the plant from the tropical forests of Costa Rica and the temperate region of the Kruger National Park, South Africa, two of the world's leading biodiversity hotspots obtained.
With the sequencing of the matK gene (for a different code for different plant species and an almost identical code to the plants of the same species) were able to distinguish between a thousand ways they Orchids - plants known for theirDifficulties because of their appearance almost identical differ, particularly when sterile. As a result, the plant identified by DNA "barcodes" (Medical News Today, February 6, 2008), "... what was regarded as a species of orchids [find] two different species living on different tracks of different [with]-shaped flowers adapted for different pollinating insects.
Scientific analysis, in which gene matK areas divided into five yearsstated that the area 3 (known as 3 ') region is the range most effective in phylogenetic information. When broken down further by 306 of the 140 bp 3 'region were phylogenetically informative.
Establishing the gene matK barcode function using the rbcL gene complements, marks an important breakthrough in plant research because it offers a wide range of applications, scientists and plant can be used by thisTaxonomy / taxonomy and the ability to bridge the gap, close to the time between plant and animal barcodes.
These potential applications include, but are not limited to:
1. Precise identification of plant species, particularly the cryptic species are difficult to distinguish, possibly leading to the discovery of new species. Currently, as Anna-Marie Lever, said DNA "barcode" has plants only "some experts [can] identify exactlythe composition of the hot spots of plant biodiversity. "
2. Precise identification of the botanical components in foods and medicines.
3. Detection of unwanted plant material in processed foods by inspectors from the health authorities.
4. Monitoring of plant species (eg immigration).
5. Finding endangered species for the conservation of habitat.
6. Detection of illegal transportation / trading of endangered species to protect them from potential harm.
7. The confirmation or identification of plants and insectsAssociations.
8. Facilitate expansion and botanical medical research.
But before this can be achieved, the following steps:
1. Creation of a genetic database in a handheld scanner, so that data can be uploaded to be available on the basis of a simple leaf / tissue sample. To improve the identification of species and accelerate the discovery of new species, has a huge database and are available online.
2. Establishment of aSearch method or algorithm for searching and access to DNA barcode information from a database online.
3. Define a set of standard reference samples of DNA using existing plant of the botanical gardens, herbaria, museums and other repositories of DNA content (bar codes only extractions bp matK and rbcL genes contains based). For example, the Consortium for the Barcode of Life Smithsonian Institution's National Museum of Natural History in Washington DCidentified more than two million of the estimated ten million species of plants, animals and fungi (many as yet unnamed) and the Royal Botanic Gardens, Kew now has more than 23,000 DNA samples of the plants. This is particularly important as cool collection efforts designed to preserve the DNA of each plant species, are not practical because it would require much time and effort.
4. collection efforts in accordance with international law (eg Convention on Biological Diversity) has madeprotect habitats and ensure the integrity of the sample. By W. John Kress and David L. Erickson DNA barcodes: the genes, genomics and bioinformatics, as the collection efforts are needed because current models are limited in quantity and may be composed of degraded DNA. Currently, the collection efforts are carried out in temperate (Iceland Plummer, MD and New York City, and others) and tropical (Forest Dynamics Plot, Panama, etc.) areas.
With a seal of approval by the UNdeclared 2010 the International Year of Biodiversity, "strong global effort to barcode 500,000 of 1.7 million named species of plants, animals and fungi targeted by 2015, which by international groups of researchers and groups / projects as pursued as the Consortium for the Barcode of Life, and soon, the International Barcode of Life (Ibol), a project that is scheduled to launch in July 2010. In addition, Paul Hebert, the biologist, the movement of the bar code and an inspiredIbol instrumental to the project, to scan Life (National Geographic, May 2010) said: "The approach is scalable to meet the world [so that by 2025 all] human species are frequent with barcode [were]."
In relation to plants, such as technology improves to use the matK gene rbcL genetic code and by creating a common database, the production of low-cost hand-held scanner suitable for analysis of leaf samples and matched tissue barcode DNAwith database information, the field of botanical research and phylogeny will benefit greatly especially for the identification and classification system will be available for more than a few experts. In addition, the identification and classification to be more precise than sole reliance on visual inspection of the morphology and physics (especially in terms of cryptic species) that, while endangered species can be easily traced and protect better, and peoplehave greater certainty about the food, the consumption of beverages and / or medicine it.
Other references:
José A. Jurado-Rivera, P. Vogler Alfried, Chris AM Reid, Eduard Petitpierre, and Jesús Gómez-Zurita. DNA barcoding insect host plants. The Royal Society. 17. October 2008.
Khidir W. Hilu and Liang Hongping. The matK gene: sequence variation and application for the classification of plants. American Journal of Botany 84 (6). 1997th
Steve Newmaster,Aron Fazekas, Royce Steeves and John Janovec. Army tests barcoding regions of South America, wild nutmeg trees. Botany 2008th
ไม่มีความคิดเห็น:
แสดงความคิดเห็น