Non-destructive DNA extraction in ticks : a method to keep the shape !
Résumé
“My DNA? At the price of my good shape? No way” it is what are thinking all of the ticks when we ask them for more information about their genetic and morphology. Even old specimens from Museum collection (the alcohol-preserved ticks), want to keep their integrity. That is why, to help researchers in their study and to preserve morphology (and mood) of these specimens, non-destructive DNA extraction protocol was applied on Ixodes ricinus (larvae, nymphs and adults -female and male) conserved since 2007 in alcohol 70%. The method can extract on average of 69ng of DNA (in a final volume of 30 µl). 16S fragments were successfully amplified and sequenced for all the stages. Photo shoot under stereomicroscope for all of the stages, reassures ticks and researchers that ticks keep there chitinous exoskeleton intact but clarified. Using the outline-based geometric morphometry approach, the contour of the first coxa of larvae, nymphs and adults, a diagnostic character frequently used to discriminate different species, was investigated. Our result shows that the coxa 1 is not altered by the DNA extraction. The method is fast, cheap. No body shaming for ticks: the non-destructive DNA extraction preserves the ticks and their morphological characteristics for future reference. It is a valuable aid for integrative taxonomy of ticks.