This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Ammazzalorso AD, Zolnik CP, Daniels TJ, Kolokotronis S.2015. To beat or not to beat a tick: Comparison of DNA extraction methods from ticks (Ixodes scapularis)PeerJ PrePrints3:e842v1https://doi.org/10.7287/peerj.preprints.842v1
Background. Blacklegged ticks (Ixodes scapularis) are important disease vectors in the United States, known to transmit a variety of pathogens to humans, including bacteria, protozoa, and viruses. Their importance as a disease vector necessitates reliable and comparable methods for extracting microbial DNA from ticks. Furthermore, to explore the population genetics or genomics of this tick, appropriate DNA extraction techniques are needed for both the vector and its microbes. Although a few studies have investigated different methods of DNA isolation from ticks, they are limited in the number and types of DNA extraction and lack species-specific quantification of DNA yield. Methods. Here we determined the most efficient and consistent method of DNA extraction from two different developmental stages of I. scapularis – nymph and adult - that are the most important for disease transmission. We used various methods of physical disruption of the hard, chitinous exoskeleton, as well as commercial and non-commercial DNA isolation kits. To gauge the effectiveness of these methods we quantified the DNA yield and confirmed the DNA quality via PCR of both tick and microbial genetic material. Results. DNA extraction using the Thermo GeneJET Genomic DNA Purification kit resulted in the highest DNA yields and the strongest, most consistent PCR amplification. We also found that physical disruption of the tick exoskeleton was most effective using cross-sectional cutting compared to any type of bead-beating matrices used. Storing ticks at -80°C resulted in considerably higher DNA yields than those from ticks stored in ethanol. Discussion. We contrasted a variety of readily available methods of DNA extraction from single individual blacklegged ticks and presented the results through a quantitative and qualitative assessment.