Robust DNA Isolation and High-throughput Sequencing Library Construction for Herbarium Specimens

Area of Science:

• Genomics
• Botany
• Molecular Biology

Background:

• Herbarium specimens are crucial for biological studies but present challenges like degraded DNA and destructive sampling.
• Existing methods for DNA isolation from herbarium samples are often not scalable or require sample-specific modifications.

Purpose of the Study:

• To develop a robust, scalable, and high-throughput DNA isolation and library preparation protocol for herbarium specimens.
• To overcome limitations of degraded DNA and minimize destructive sampling in phylogenetic studies.

Main Methods:

• Optimized tissue grinding and DNA isolation from dried plant material.
• Modified library size selection and introduced an optional reamplification step for low-yield libraries.
• Developed a beginning-to-end protocol for DNA isolation and high-throughput library construction.

Main Results:

• The protocol successfully isolates DNA and prepares libraries from low-quality herbarium specimens without sample-specific modifications.
• Optional reamplification rescues low-yield libraries, avoiding further destructive sampling and introducing no discernible sequencing bias.
• The protocol processes 24 samples in under 13 hours with 8 hours of hands-on time.

Conclusions:

• This protocol offers a fast, comprehensive, and scalable method for DNA isolation and library preparation from herbarium specimens.
• It is adaptable for various plant lineages and crucial for large-scale sequencing projects utilizing historical plant material.
• Potential limitations include extremely degraded DNA and inhibitory secondary metabolites in certain plant samples.