Experimental Validation of Transposable Element Insertions Using the Polymerase Chain Reaction (PCR).

Transposable elements (TEs), also known as transposons, are repetitive DNA sequences, present in virtually all organisms, that can move from one genomic position to another. TEs can be a source of mutations with important consequences for organisms. Despite their interest, its repetitive nature has made their study very challenging. However, the emergence of new sequencing technologies that allow obtaining long-read sequences, has improved the in silico de novo detection and annotation of TEs. The de novo annotation of TEs has already been performed in several organisms including the fruit fly Drosophila melanogaster. Yet, experimental validation can be used to confirm the presence of TEs in specific D. melanogaster natural populations. Here, we present a step-by-step protocol to experimentally validate by polymerase chain reaction (PCR) the presence and/or absence of TEs in natural populations of D. melanogaster. This detailed protocol has been implemented in the participant high schools of the Citizen Fly Lab activity that is part of the international citizen science project Melanogaster: Catch the Fly! ( https://melanogaster.eu ). Specifically, the students collaborate with the scientists of the European Drosophila Population Genomics Consortium (DrosEU) in the experimental validation of new genetic variants, previously identified using bioinformatic techniques.