DNA Barcoding Process and Applications
18.3 هزار بار بازدید -
3 سال پیش
-
DNA barcoding is a method
DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that, by comparison with a reference library of such DNA sections (also called "sequences"), an individual sequence can be used to uniquely identify an organism to species.
1. Sampling and preservation
Barcoding can be done from tissue from a target specimen, from a mixture of organisms (bulk sample), or from DNA present in environmental samples (e.g. water or soil). The methods for sampling, preservation or analysis differ between those different types of sample.
2. DNA extraction, amplification and sequencing
DNA barcoding requires that DNA in the sample is extracted. Several different DNA extraction methods exist, and factors like cost, time, sample type and yield affect the selection of the optimal method.
When DNA from organismal DNA samples is amplified using polymerase chain reaction (PCR), the reaction can be affected negatively by inhibitor molecules contained in the sample. Removal of these inhibitors is crucial to ensure that high quality DNA is available for subsequent analyzing.
Amplification of the extracted DNA is a required step in DNA barcoding. Typically, only a small fragment of the total DNA material is sequenced (typically 400–800 base pairs) to obtain the DNA barcode. Amplification of DNA material is usually focused on smaller fragment sizes approx 200 base pairs), as DNA is more likely to be fragmented than DNA material from other sources. However, some studies argue that there is no relationship between amplicon size and detection rate of DNA.
3. Markers selection
Markers used for DNA barcoding are called barcodes. In order to successfully characterize species based on DNA barcodes, selection of informative DNA regions is crucial. A good DNA barcode should have low intra-specific and high inter-specific variability and possess conserved flanking sites for developing universal PCR primers for wide taxonomic application. The goal is to design primers that will detect and distinguish most or all the species in the studied group of organisms (high taxonomic resolution). The length of the barcode sequence should be short enough to be used with current sampling source, DNA extraction, amplification and sequencing methods.
Ideally, one gene sequence would be used for all taxonomic groups, from viruses to plants and animals. However, no such gene region has been found yet, so different barcodes are used for different groups of organisms, or depending on the study question.
Some of the tools are:
a. Spider
b. Bronx
c. ecoPrimers
d. CAOS Software
e. Taxl
Advantage Of DNA barcoding
• Protection of Endangered Species Conservation
• Tracking adulterations
• Identifying Agricultural pest
• Water quality testing
• Identification of all life stages, eggs, larvae, nymphs, pupa, adults
• Identification of fragments or products of organisms
• Identification of stomach contents, trace ecological food-chains
• Food control
• Customs control
• Invasive species control
• Disease vector control
• Police
• Agriculture
• Forestry
• Education
Thank you for watching
If you like the video please press like button, share, comment, and subscribe the channel.
3 سال پیش
در تاریخ 1400/02/16 منتشر شده
است.
18,362
بـار بازدید شده