A 'forensic quality' service from the UK's 1st private DNA fingerprinting laboratory 0800 193 3362   edna@cellmark.co.uk

Frequently Asked Questions (FAQs)

Sampling and returning your samples

Is there a risk of the sampler contaminating the samples?

There is a risk of transferring eDNA on your boots, equipment etc. as you move from pond to pond. You should make sure that you never go in the water when sampling a pond. When possible take your eDNA samples before you do other surveys. Exceptionally muddy/wet conditions may also increase the chances of contamination due to splashing of GCN containing water or mud onto clothing/boots or equipment.

How should I decontaminate equipment?

We recommend using chlorine based bleach to destroy any DNA on boots and equipment.

How do you take eDNA samples?

All pond sampling must be done following the Natural England technical advice note
A copy of our sampling instructions is sent out with every kit.

What is in a kit?

Each kit will contain the following items:

  • A sterile 30 mL ladle,
  • A sterile self-supporting Whirl-Pak plastic bag with 1 L capacity,
  • A sterile 10 mL pipette to resample the pond water,
  • 6 sterile 50 mL centrifuge tubes containing preservative (Absolute Ethanol (200 Proof),
  • 2 pairs of sterile gloves,
  • 1 gripseal bag
  • 1 Mail-Tuff return envelope,
  • 1 sample return form and
  • 1 instruction sheet.

The sample tubes, packaging and sample return form have all been pre-barcoded for your convenience.

How many kits do I need?

1 kit can be used for ponds up to 1 hectare in size.

For larger bodies of water, Natural England recommends using 1 kit per hectare. If multiple kits are required, we recommend that the circumference of the lake is divided into equal sections based on the number of kits to be used. One kit is then used to sample each of the sections.

Why are sampling points spread around the pond?

The concentrations of GCN eDNA may be different in different regions of the pond. GCN may favor some areas of a pond more than others. Their eDNA is likely to be more concentrated in the more heavily populated areas. Sampling multiple areas increase the chances of collecting GCN DNA if they are present.

Why is 600ml of pond water collected when only 90ml is sent for analysis?

This is in accordance with the Natural England guidelines.

Why is the water column mixed before sampling?

The DNA/cellular material gradually sinks in the water column and will often be present in larger amounts close to the pond bottom. Try to avoid collecting sediment. It can interfere with the analysis.

Does it matter if I collect plant material, zooplankton in my water sample?

Small amounts of these materials do not affect the analysis. Avoid transferring larger debris to the 50 ml sample tubes. Try to avoid collecting bottom sediment.

Why should sediment be avoided?

  • There is the potential for GCN DNA to remain in the sediment when there is no GCN activity in the water body during the current breeding season
  • Sediment can cause inhibition of the PCR analysis used to detect GCN eDNA which could lead to an inconclusive result
  • Sediment can interfere with the DNA extraction procedure

What happens if my samples contain a lot of sediment?

Please try to avoid including sediment in the sample as it can interfere with the laboratory testing processes. Upon sample receipt, we inspect the samples for the presence of sediment, algae, precipitates and any other debris. If samples contain excess amounts of debris we may have to fault the sample. In this instance we will contact the sampler to highlight the issue. On occasion this may require the submission of a new sample - a replacement kit will cost £25.

Does it matter if algae is present in the sample?

Upon sample receipt we inspect your samples for the presence of sediment, algae, precipitates and any other debris. Algae can make the DNA extraction more difficult to perform so it is helpful it can be avoided.

What happens if some of the solution in the 50ml tube spills?

If some of the ethanol solution spills, add proportionately less of the pond sample to that tube. If a large amount of the ethanol has spilled or multiple tubes have spilled, please call us on 0800 193 3362 for advice.

How long can kits be kept prior to sampling?

Natural England’s advice is that kits should be used within 3 months. Ideally, you should return the kits as soon as possible after the sampling is completed.

When can I return my samples?

Ideally, you should return the kits as soon as possible after the sampling is completed. However, you can return the kits to the laboratory within two weeks after pond water collection. If samples must be stored for a few days prior to returning them to the laboratory please store them in the refrigerator.

How do I return my samples to you?

There are three options:

  1. We operate a 24/7 365 sample reception service, so if you’re local, you can drop it into our reception (Unit 16) in Abingdon, however for security reasons please phone in advance (during normal office hours) to let us know who will be dropping the sample off and an approximate time.
  2. Use a Cellmark courier. Call our customer services department on 0800 193 3362 and they will arrange a courier and email you the correct labels for you to attach to the outer packaging. Our standard courier charge is £20 however, this rises to £35 if you are using our Next Day testing service.
  3. Using your own courier. Please contact us to confirm your choice so we can plan for your sample’s arrival.

I have kits left over what should I do with them?

Unused sampling kits can be returned to Cellmark so we can dispose of the chemicals in the tubes safely.  Although we do make a small charge for unused sampling kits (£20 per kit), we do not charge the full analysis fee as we understand that there are many factors which can change the testing requirements throughout the course of the season.  If payment has been made in advance, Cellmark will refund the cost of any unused sampling kits which have been returned, minus the nominal fee.

Can I reuse parts of kits?

You should never reuse any parts of the kit. Once you have used your ladle, gloves, Whirl-Pak bag and pipette, these must be disposed of. The risk of contamination is too high for them to be reused.

My kits were not collected by the courier when expected - will they still be okay?

The samples should be okay at ambient temperature for a few days and they can be stored for up to 1 month at 4°C prior to laboratory analysis.

Do the samples degrade during transit to the laboratory?

The ethanol in the 50 ml tubes helps to preserve the DNA. Refrigeration also slows the degradation process. DNA degradation will be faster at ambient temperature but should not have a large effect on sample outcome. It may be advisable to refrigerate the sample for a few days in excessively hot weather.