Development: DNA & Detection Dogs

DNA

DNA to indicate relationships, movements etc.

If we are to eradicate mink from East Anglia – a vast region covering thousands of square kilometres, with a huge number of waterways and water bodies – we will need to use every scrap of information about these animals that might be available. We will have to understand how far they travel, and when they travel. We will need to know about their breeding biology and behaviour, how large are their territories and where they live at different times of year. One of the most powerful tools for providing answers to these questions is in every cell of every mink – their genetic identity, their DNA. By taking a few cells from a mink, we can potentially identify its parents and siblings, learn where it was born and find out where it has been. This is forensic science being put to use in the service of nature conservation.

To build the reference collection that will allow us to interpret mink DNA, we routinely take a small piece of tissue from every animal caught, and every mink found dead on a road. These samples will allow us to build up a picture of the genetic diversity of mink across our region, and to look for patterns. For example, if we were to find that the mink in north Norfolk were genetically no different from those in south Essex or west Cambridgeshire, we would infer that there is a great deal of mixing in the population. But if there are clusters of mink with different DNA profiles within our region, we could be sure that there is little or no mixing. If we take the DNA of a territorial adult female in coastal Suffolk, and then find that young animals captured in Norwich or Hatfield are her offspring, this helps us understand how far juveniles disperse from their natal area. Knowing this degree of dispersal is vital, for example, for us to plan a trapping regime that will keep our project Core Area (essentially Norfolk and Suffolk) free of immigrating mink.

The Papers section gives examples of how studying mink DNA can help better understand mink populations.

eDNA

eDNA to help us detect mink at low densities

When mink have been almost, but not quite, removed from East Anglia, finding the whereabouts of the last animals will be a major undertaking. A suite of techniques will be required to find them, including trained mink dogs (see below), but all are labour intensive and focus on individual animals. It would save a huge amount of money and time if we had a way to be able to say that a particular river or lake is currently free of mink, so we can focus scarce resources on places where mink still remain.

Until very recently, there seemed no prospect of having a way to make such a determination, but advances in the sensitivity of molecular testing now offer just such a possibility. Remarkably, geneticists can now detect the presence of a few cells of an organism in water samples. Science fiction has been turned into science fact, as it has now become almost routine to collect a litre of water from a river and be able to say whether otters, crayfish, tench, water hyacinth or indeed mink live upstream of the collection point. Cells are put into the water when an animal swims, urinates or defaecates in it. Much research work is required to turn this remarkable discovery into an effective tool for us, though. For example, if mink cells are found, does this mean the animal(s) were present yesterday, within the past month, or within the past year? Can we say how many animals are present, or how far away they are? If no mink cells are present in one sample, do we need to repeat the sampling and testing to be sure the species is absent? So many questions, and as yet not many answers. But this field of science, investigating what is known as environmental (e)DNA, is developing rapidly, and trials are already underway to provide the answers that will soon make eDNA an invaluable tool in our quest to eradicate mink from the Eastern Region.

Training for River Wardens in Essex on eDNA sampling

Click image to enlarge

Detection Dogs

Mink Dogs to h