Molecular Techniques for Analysis of Biodiversity by Agarose Gel Electrophoresis

Abstract

Molecular techniques based on DNA analysis have become an indispensable tool for the identification and classification of organisms, addressing the limitations of taxonomy based on morphological characters. There are different methods for the analysis of the variability of DNA which can provide unique genetic signatures capable of distinguishing closely related species, hybrid specimens or even individuals within the same species. Here we describe two methods that allow species identification by agarose gel electrophoresis separation techniques. DNA barcoding is a method of identifying any species based on a short DNA sequence amplified by PCR from a specific region of the genome, as most species have distinct genetic markers, or “barcodes”, that are unique to them. By performing a bioinformatic analysis of the PCR-amplified barcode of an unknown sample against a database of known barcodes, it is possible to identify the species to which the sample belongs. On the other hand, Random Amplified Polymorphic DNA (RAPD) is used to detect genetic variation within a species. It is a PCR-based method that employs short, random primers to amplify DNA fragments from genomic DNA. The amplified fragments are then separated by gel electrophoresis and visualized as a banding pattern on the gel.