DNA Barcoding

Introduction

DNA barcoding is a method of identifying species that uses short DNA from one or more specific genes. The premise of DNA barcodes is that by comparing such a range of DNA (also called a “sequence”) with a reference library, a well-known black man uses Strip in a supermarket using one sequence. Like a scanner, you can clearly assign an organism to a species. Use of UPC barcodes to identify items in inventory using a reference database.  These “barcodes” are used to identify parts of unknown species or organisms, simply catalog as many taxa as possible, or demarcate species in comparison to traditional classification methods. May be used. Barcodes identify different groups of organisms using different genetic regions. The most commonly used barcode region in animals and some protists is part of the cytochrome c oxidase I gene (COI or COX1) found in mitochondrial DNA. Other genes suitable for DNA barcoding are the internal transcription spacer (ITS) rRNA commonly used in fungi and Rubisco used in plants. Microorganisms are detected using various genetic regions. For example, the 16S rRNA gene is commonly used to identify prokaryotes, while the 18S rRNA gene is primarily used to detect eukaryotes of microorganisms. These gene regions are selected because they have fewer intraspecific (intraspecific) mutations than interspecific (interspecies) mutations known as “barcode gaps.” Some applications of DNA barcoding include: Identify plant leaves even when flowers and fruits are not available. Identification of pollen collected in the body of pollinating animals; identification of insect larvae that may have less diagnostic function than adults. Alternatively, examine the animal’s diet based on stomach contents, saliva, or feces. When barcodes are used to identify organisms from samples containing DNA from multiple organisms, the term DNA meta-barcode is used. DNA metabarcoding of diatom communities in rivers and streams used to assess water quality.

DNA Fingerprinting

DNA fingerprinting (also called DNA profiling) is the process of characterizing a person’s DNA. DNA analysis designed to identify a species rather than an individual is called a DNA barcode.  DNA profiling is a forensic technique in criminal investigations that compares the profile of a criminal suspect with DNA evidence to assess their likelihood of being involved in a crime. It is also used in paternity testing, immigration status, genealogy, and medical research. DNA profiling has also been used to study animal and plant populations in  zoology, botany, and agriculture.

To create a DNA barcode database, the following steps are essential: 

1. DNA barcode projects obtain samples from a variety of sources, such as amateur taxonomists’ private collections and museum collections (e.g. natural history museums, zoos, botanical gardens, and seed banks). Museum specimens are carefully screened for DNA quality to ensure reliable DNA barcodes. Fresh ingredients collected from the ground by citizen scientists. Professional GBOL taxonomists rely on the enthusiasm and active support of qualified citizen scientists. They make a significant contribution to the collection, proper preservation and identification of organisms for DNA barcodes.
2. Taxonomic identification and collection data are recorded for each sample (i.e. sampling location and date, geographic coordinates, collection method, collector name, etc.).
3. Organisms will be photographed in their natural habitat and in the laboratory.
4. Vouchers are stored in the collections of their respective GBOL institutions.
5. In the lab, a technician separates a small piece of tissue from each sample and extracts the DNA.
6. DNA barcode regions are separated and replicated using a process called PCR (polymerase chain reaction) amplification.
7. A DNA barcode is generated and consists of a sequence of four different characters with a length of hundreds of base pairs (e.g. CAATCGGTAA…). These letters represent the four nucleic acids that make up DNA: adenine, guanine, thymine, and cytosine.
8. Sample sequences and metadata (collection data, classifications, photographs) are checked for integrity and quality by professional GBOL scientists.
9. GBOL data is uploaded to the Barcode of Life Data Systems (BOLD) database, an international reference library for DNA barcodes. BOLD is an online workbench that facilitates the collection, management, analysis, and use of DNA barcodes.

Applications

Uses of DNA barcodes include identification of new species, food safety assessment, identification and evaluation of mysterious species, detection of alien species, identification of endangered and endangered species, stage of eggs and larvae. This includes associating adult species and securing intellectual property rights for biological resources. Develop a global management plan for conservation strategies and elucidate food niches. DNA barcode markers can be applied to answer basic questions in taxonomy, ecology, evolutionary biology, and conservation. This includes community assembly, species interaction networks, taxonomic discoveries, and assessment of conservation priorities.

• Detection of invasive species: Alien species can be detected using barcodes. Barcodes may be suitable, for example, for species detection in border control. Here, rapid and accurate morphological identification is often not possible due to similarities between different species, lack of sufficient diagnostic characteristics and/or lack of taxonomic expertise. Barcoding and metabarcoding can also be used to screen for ecosystems of invasive species and to distinguish morphologically similar native species from invasive species. 

• Identification of species: Short DNA sequences or markers from a specific section of the genome can be used to create a DNA barcode for species identification. When traditional approaches are ineffective, molecular methods come in handy. DNA barcoding is useful for identifying larvae for which few diagnostic features are available, as well as for identifying different life phases (e.g., larval and adult) in many animals.  In order to monitor unlawful trade, barcoding techniques are employed to identify species listed in the Convention on International Trade in Endangered Species (CITES) appendices
• Barcoding for food safety: DNA barcoding is a critical method for assessing the quality of food products. The goal is to ensure food traceability, reduce food piracy, and assess local and traditional agro-food production. Another goal is to protect public health; for example, metabarcoding can be used to distinguish deadly mushrooms from edible ones, or to identify groupers that cause Ciguatera fish poisoning from meal remains (Ref)
• Biomonitoring and ecological assessment: The presence of endangered species for conservation efforts (Ref) or indicator species indicative of specific ecological circumstances (Ref), such as excess nutrients or low oxygen levels, can be assessed using DNA barcoding
• Delimiting cryptic species: DNA barcoding allows enigmatic species to be identified and recognised. The outcomes of DNA barcoding tests are, however, dependent on the analytical methods used, therefore employing DNA barcodes to delimit cryptic species can be as subjective as any other kind of taxonomy

Conclusion 

DNA barcoding is a rapid and accurate species identification system. It creates a more accessible ecological system using a short DNA sequence instead of the entire genome and is used for eukaryotes and prokaryotes. Short DNA sequences are generated from a standard region of the genome called a marker. This marker is different for different species such as CO1 cytochrome c oxidase 1 for animals, matK and rbcL for plants, and the (ITS) internal transcriptional buffer for fungi. It has many uses in various fields such as agriculture, conservation of natural resources, protection of endangered species, water quality, conservation of natural resources, identification of medicinal and aromatic plants.