Simple DNA extraction for museum beetle specimens to unlock genetic data from historical collections

Abstract

Museum beetle specimens are valuable resources for genetic analyses; however, obtaining DNA from aged specimens remains challenging due to degradation, desiccation, and contamination. In this study, we present a simple, low-cost protocol for extracting DNA from museum beetles, optimized using cetyltrimethylammonium bromide (CTAB). This method effectively addresses common issues such as DNA fragmentation and contamination, enabling the recovery of DNA suitable for downstream applications such as PCR and next-generation sequencing. It provides a reproducible, non-destructive approach to extracting genetic material from fragile beetle specimens, thereby facilitating molecular investigations in fields such as taxonomy and conservation biology. The protocol is summarized as follows:•A method for DNA extraction is optimized for museum beetle specimens preserved for over 45 years.•The protocol is non-destructive and compatible with PCR and next-generation sequencing.•Multiple extractions can be pooled to increase yields, particularly when DNA concentrations are low. This method broadens the possibilities for genetic analysis of historical specimens, offering new insights into long-term ecological and evolutionary processes.

Keywords: CTAB method; DNA extraction; DNA extraction and PCR amplification of COI barcode; Museum beetle; Next-generation sequencing; PCR amplification.

Graphical abstract

Fig. 1

Representative images of museum beetle specimens used in this study. Aulacophora foveicollis (Lucas, 1849) (Coleoptera: Chrysomelidae: Galerucinae) is on the left (A). Callosobruchus phaseoli (Gyllenhal, 1833) (Coleoptera: Chrysomelidae: Bruchinae) is on the right (B).

Fig. 2

Procedure for DNA extraction from the museum beetle specimens.

Fig. 3

Agarose gel electrophoresis of the genomic DNA from museum beetle samples. Lanes 2–8 (Top Gel: 3A) and the PCR-amplified COI barcode marker (650 bp) (Bottom gel: 3B) from the respective samples, along with Lane 1: 1 kb DNA ladder (Top gel) and 100 bp DNA ladder (Bottom gel), were marked as M.