eDNA Kit Instructions

Avoiding contamination is essential for ensuring reliable eDNA results. Follow these guidelines to reduce the risk:

1. Use gloves

• Each kit includes one pair of sterile nitrile gloves.

• If multiple people handle samples or equipment, purchase extra gloves and ensure everyone wears them.

• Use a fresh pair of gloves at each site and avoid touching surfaces or materials unnecessarily.

2. Maintain sterility of kits

• Kits are sterile until opened.

• Open one kit at a time and keep contents inside the bag until needed.

3. Sterilise equipment

• Sterilise all tools (trowels, soil cores, etc.) between sites using a 1:10 bleach solution.

• EnviroDNA provides guidance for properly sterilising any reusable equipment for your project.

4. Avoid sampling underfoot

• Footwear can introduce contamination.

• Sterilise footwear between sampling locations if soil pathogens (e.g., Cinnamon fungus) are known or suspected.

The comprehensiveness and quality of your eDNA results can be impacted by many factors. Two common factors that can be mitigated during sampling are DNA Degradation and PCR Inhibition.

DNA Degradation refers to the breakdown of DNA. Degradation occurs naturally occurs over time, and can be accelerated by environmental and biological factors.  When DNA degrades, it becomes more difficult to identify and this affects the results of eDNA analysis.

Tips to avoid DNA degradation:

• Follow the protocols provided: Our kits come sterilised and include sealed containers and preservative agents to reduce the risk of degradation.
• Use new sampling kits: Sampling kits containing preservative (syringe water kits, swab kits, and Smith Root self-preserving filters) must be used within 12 months of purchase. Store kits in a cool, dry place out of direct sunlight until ready to use.
• Collect replicate samples: Increase sample replication to collect as much DNA as possible. Replication is particularly important in warm climates and areas with high UV intensity.
• Dry your Smith Root filters: After sampling, expel all water from the filter by inverting the filter and pump air through for at least 10 seconds.
• Store samples appropriately: Store samples in a cool, dry place out of direct sunlight until they can be returned to us.
• Return collected samples as soon as possible:
  • Soil: must be received within 5 days of collection.
  • Water and swabs: must be received within 10 days.
  • Smith Root self-preserving filters: must be received within 30 days.
• Ship soil samples appropriately: Store soil samples in the fridge until they can be shipped to us. Ship soil samples using cold storage transportation, or in an esky with sealed freezer packs only (no ziplock bags or loose ice).
• Do not freeze: Thawing denatures DNA, so do not freeze any samples unless specifically instructed.

Inhibition occurs when substances present in a sample interfere with the PCR reaction, affecting the amplification of target DNA or impeding the enzyme responsible for the PCR reaction. Inhibition can therefore prevent or reduce detection of target taxa.

Tips to avoid sample inhibition:

• Agricultural environments: Avoid sampling when agricultural spraying is occurring nearby, where visible signs of industrial or agricultural runoff are observed, or directly near livestock.
• Monitoring rainfall: Avoid sampling directly after rain (wait at least 3 days before collecting samples).
• Disturbing sediment: Avoid stirring up sediment during water sampling, which can clog the filter and reduce sample volumes. Target areas of flowing water, and avoid areas where sediment/debris accumulates.
• Calcium/Chalk: Avoid sampling waterways with a high calcium or chalk content.