Holmquist, A. J. | Search bioRxiv

bioRxiv2024

Towards large-scale museomics projects: a cost-effective and high-throughput extraction method for obtaining historical DNA from museum insect specimens

Natural history collections serve as invaluable repositories of biodiversity data. Large-scale genomic analysis would greatly expand the utility and accessibility of museum collections but the high cost and time-intensive nature of genomic methods limit such projects, particularly for invertebrate specimens. This paper presents an innovative, cost-effective and high-throughput approach to extracting genomic DNA from diverse insect specimens using single-phase reverse immobilization (SPRI) beads. We optimized PEG-8000 and NaCl concentrations to balance DNA yield and purity, reducing reagent cost to 6-11 cents per sample. Our method was validated against three widely used extraction protocols, and showed comparable DNA yield and amplification success to the widely used Qiagen DNeasy kit. We successfully applied the protocol in a high-throughput manner, extracting DNA from 3,786 insect specimens across a broad range of ages, taxonomies, and tissue types. A detailed protocol is provided to facilitate the adoption of the method by other researchers. By improving one of the most crucial steps in any molecular project, this SPRI bead-based DNA extraction approach has significant potential for enabling large-scale museomics projects, thereby increasing the utility of historical collections for biodiversity research and conservation efforts.

genomics↗

bioRxiv2023

The importance of habitat type and historical fire regimes in arthropod community response following large-scale wildfires

Wildfires are increasingly altering ecosystems, posing significant challenges for biodiversity conservation and ecosystem management. In this study, we used DNA metabarcoding to assess the response of arthropod communities to large-scale wildfires across diverse habitat types. We sampled six reserves within the University of California Natural Reserve System (UCNRS), each which was partially burned in the 2020 Lightning Complex wildfires in California. Using yellow pan traps to target pollinators, we collected arthropods from burned and unburned sites across multiple habitat types including oak woodland, redwood, scrub, chamise, grassland, forest, and serpentine habitats. We found no significant difference in alpha diversity values between burned and unburned sites; instead, seasonal variations played a significant role in arthropod community dynamics, with the emergence of plant species in Spring promoting increased pollinator richness at all sites. Compositional similarity analysis revealed that burn status was not a significant grouping factor when comparing all sites. Instead, community composition primarily varied across reserves, indicating distinct pools of arthropods structured geographically. Habitat type played a crucial role in determining the response of arthropod communities to fire. While communities in grasslands and oak woodlands exhibited recovery following burn, scrublands experienced substantial changes in community composition. Our study highlights the importance of examining community responses to wildfires across broad spatial scales and diverse habitat types. By understanding the nuanced dynamics of arthropod communities in response to fire disturbances, we can develop effective conservation strategies that promote resilience and maintain biodiversity in the face of increasing wildfire frequency and intensity driven by climate change.

ecology↗