DNA barcoding is the process of using a short sequence of an organisms genome to identify it is a specific species. DNA barcoding was first introduced in 2003 by a Canadian scientist, Paul Herbert. A researcher at the University of Guelph in Ontario, he presented the idea as a way to identify and distinguish species. Using pre exisiting classifications scientists can use DNA barcoding to distinguish an unknown specimen. Just by looking at an organism with a naked eye you are unable to precisely tell what it is. If you had two organisms which look extremely similar you would be unable to tell them apart. DNA barcoding enables you to accurately distinguish the two. This scientific endeavour links to the SHE topic of DNA and proteins as it uses the DNA of an organism to create for it a DNA barcode sequence which they can store to be used to identify and analyse other specimens.
DNA, deoxyribonucleic acid, is a self replicating material found in all living organisms which carries genetic information. It is a our hereditary material made up of a unique genetic code which determines our characteristics and qualities. This unique code is what made us different from everyone else, giving us different eye colours and hair colours. DNA can also make us more susceptible to diseases and hereditary illnesses. DNA is found in practically every cell in an organisms body and it gives our body the instructions it needs for our bodies to function. DNA is structured by two strands which have the appearance of being twisted, made up by sugar and phosphate groups. The bases of the strands are connected to form a ladder-like shape where A sticks to T, and G sticks to C to create the strands that connect the two strands. This shape is called a double helix. Each of these two strands contain nucleotides, a compound which is the structural unit, the building block of DNA. The strands also contain individual units made of a phosphate molecule, a nitrogen region and deoxyribose. It contains four bases: adenine, cytosine, guanine and thymine which are all nitrogen containing regions. These four bases form the genetic code.
The process of DNA barcoding is carried out in a laboratory by technicians. They extract a small piece of tissue from the specimen which they can extract the DNA from. They then amplify the following parts; RBCL which contains Rubidium chloride, an alkali metal halide which can be used for many things including biology and chemistry, the COI gene which is a protein in humans and ITS gene which is DNA which sits between ribosomal RNA and rRNA genes in the chromosome, using a process called PCR. PCR or Polymearase chain reaction is a process in molecular biology which amplifies DNA and creates copies of it. PCR comes from three stages; Denaturing in which the DNA sample is heated to separate it into two seperate strands, Annealing in which it is then cooled down to enable the DNA primers to attach to the template DNA and extending in which the temperature is raised again the the new strand of DNA is made by the Taq plymerase enzyme. This process if then repeated as many as 40 times.
An example of a time DNA barcoding was successful is in the roasted barely tea industry. This health food product was highly respected and very popular in eastern countries, especially Korea, China and Japan. It is commonly known as being a pure substance which is 100% barely powder. Controversy and disputes where arisen when the trade was claimed to have been contaminated or even subsidised by other plant components. But since the substance is such a fine powder there was no possible way to identify whether or not it had been modified and whether it was pure or not. By using DNA barcoding they are able to identify the powders plant components to determine whether it is purely barely without relying on morphology, the biological study of the physical form and specific structural features of an organism. Because of DNA barcoding they where able to detect different plant components in a batch being exported to China. After testing 13 batches of the barley tea 10 where contaminated with different plant components.
Even with a success like this DNA barcoding can still have disadvantageous and detrimental effects. One lacking subject is the inability to test a clear hypothesis and in the way they are generated and tested. Since they require different methodological approaches it has left to the inappropriate use of commonly used analytical methodological approaches. For example neighbour-joining trees, the method of re-constructing phylogenetic trees and measuring the length of the branches, establishing relationships between sequences according to a phentic criteria. These misidentifications can have serious effects on people who are using the barcodes and on scientific endeavours in the future. Another disadvantage is human error. If different labs are working on the same barcode they could end up give different taxonomic names to the same species. For DNA barcoding to be successful maintenance of records is fundamental to keep record of different species so as not to misidentify any specimens.
But even with these limitations there are many benefits to DNA barcoding that could be an essential help to science. One reason is consumer protection. DNA barcoding provides reliable identifications of different species and improved assessments of stocks which is ensuring that products are pure and truthful. It is also able to identify hazards, help with investigations into food brought illnesses and also will protect against fraud. Barcoding is also a vital help towards species at risk of extinction. By identifying these species they are able to create a reference library which they are then able to us to identify the species. This reference library with assist in identifying unknowns and proves as a beneficial tool for law enforcement, helping them to find illegal species. DNA barcoding is an incredibly beneficial practice which can help in the growth of a new species of science.
Although there is a controversial aspect to DNA barcoding. Before DNA barcoding the only way to identify species was through taxonomy. Taxonomy is the practice of classification of organisms. With now the new technology enabling DNA barcoding their is an idea that DNA barcoding will completely replace taxonomy in the studying of relationships and the naming of new species. People are arguing that DNA barcoding is only a tool that can only be used to identify DNA diversity between species and cannot replace taxonomy which classifies and provides knowledge of organism. However DNA barcoding is much cheaper and faster then taxonomy and is much easier to master and find jobs in. Others believe that instead of being separated and feuding they should work together and that they could provide benefits towards one another and will not compromise each other.
DNA barcoding is an amazing new science that enables us to precisely tell the difference between different organisms in ways we never have before. From DNA they are able to extract small pieces of tissue and find the differences in the genetic code that you can use to tell them apart. DNA barcoding is very useful for consumerism and the protection of species. Although it has the chance of inaccuracies it still has many benefits.