We are going through a crisis where several important wild species have gone extinct already and thousands more are going to go extinct if they cannot be conserved. For this reason, it becomes important to monitor if these species are genetically susceptible to disease, carry genetic abnormalities or disease-causing copies of genes.
However, obtaining samples from wild animals, so we can extract their DNA, is a very challenging task. That’s why researchers at the University of Glasgow have turned to blood sucking insects such as midges, mosquitos and tsetse flies. Using these insects, the researchers hope to develop methods of obtaining samples and monitoring wildlife that are typically very difficult to get samples from such as elephants, rhinos and tigers!
See how their work could go a long way in deciding the fate of wild species across the world. Could this innovative strategy help us to monitor and conserve the many species’ of animals that are currently endangered?
Please introduce yourself: what is your name and what do you do?
I am Anubhab Khan, I am part of a group of wildlife biologists at the Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow. We work on a wide range of species, including African wild dogs, rhinos, fishes, horses, tsetse flies and diseases. I am a wildlife population geneticist. I work on the genetics of small, isolated populations, which is a common state of endangered species. I have worked on populations of tigers, elephants, jungle cats and Indian wild dogs. I have spent lots of time in the forests of India tracking tigers to collect their samples.
Tell us about your research, what problem did you want to solve?
Small, isolated populations face several threats, including increased risk of diseases due to loss of variability at genes involved in resistance to pathogens and also increase in frequency of diseases that can be inherited. This is due both to increased inbreeding (mating between relatives) and increased effects of random processes* in small populations. To save these threatened populations, it is important to monitor the frequency of such diseases and the degree of genetic variation that is maintained to allow adaptation to pathogens and to varying environmental conditions. However, several endangered species are spotted very rarely and if spotted, cannot be disturbed for sample collection. It is extremely difficult to obtain samples from such elusive charismatic species. Better non-invasive sampling methods are thus needed to monitor these populations.
What was your solution, and how did you come up with that solution?
Here, in the University of Glasgow, we have collected lots of tsetse flies. These are insects that suck blood from wild animals in Africa. Since these flies are already sampling the blood of wildlife, we are using them to obtain DNA from the wildlife they have fed on. People have been using such indirect samples to detect host species for a while now. However, very few studies have attempted in-depth population level studies or monitor disease resistance genes using such samples.
Photo credit: Prof. Steve Torr, Liverpool School of Tropical Medicine
How will your work support endangered species?
We aim to provide an innovative solution to the problem of monitoring wildlife populations. Generally, traditional methods are very slow since they rely on direct sampling of wild populations. It is also not always possible to sample highly endangered and rare wild species. Our method will increase the range of species that could be sampled while decreasing the time needed significantly and help in measuring connectivity between populations, which could also influence the transmission dynamics of pathogens.
Once you understand the genetics of a herd, what interventions can you use to improve their prosperity?
Once we identify genetically distinct populations, we can prioritise conservation of a species or population based on the genetic data. We may also introduce a breeding male from another herd to increase the genetic mix within the herd.
What makes your innovation new/different to the work that came before it?
Previously DNA samples from invertebrates that feed on vertebrate blood (for example, biting flies and leeches), soil, water, and other sources have been used for exploring biodiversity based on “environmental DNA (eDNA)” approaches. These “anonymous” analyses generally do not involve knowing the number of individuals in a sample, but is focused on identifying what species are present. Our innovation is to extend these approaches to allow inferences about population structure, levels of inbreeding and variation at genes that are important for adaptation. This will be done using advances both in genetic sequencing technology and in bioinformatic analyses. We will also compare genetic variation of the biting flies, the hosts they feed on, and the parasites and other microorganisms carried by both the flies and their hosts.
Is team work important to this project and who do you collaborate with?
Like any research, team work is a most important component in wildlife research. Generally, wildlife researchers forge collaborations with wildlife managers, Government and non-government organisations, private companies, funding agencies, universities, communication specialists, law experts and many others. We are collaborating with other researchers in the UK working on tsetse flies, as well as local partners in Tanzania and Kenya.
Is there any particular technology that helps you in your work?
Our work depends heavily on next generation sequencing technologies. These are technologies for sequencing lots of DNA in a very short span of time. This allows us to read the genetic code and identify risks and solutions. For example, this technology has made it possible to sequence the DNA from several sources in a single step. The data generated is used to identify genetic locations where disease causing genetic variants exists. Also, we can now identify genetic locations important for disease resistance, but lacking the variation. These can then be targeted for genetic rescues.
You are in the early stages of this research, but do you have a vision for what could come next? Are there other applications for this innovative technique?
There are multiple directions the work can go in. Presently, we use very high throughput data generated by expensive DNA sequencers that require the use of super computers for analyses. Once we can identify specific genetic regions that are important, these can be monitored with much cheaper sequencers and by using lesser computational infrastructure. This will be useful for low-income countries with rich wildlife but less resources for wildlife research. Also, our methods will be used to obtain biological insights into evolutionary processes driving multiple species in the same patch of habitat. Different species react differently to various factors. Our method will make it possible to study several species at once.
*Random processes can be environmental for example, if a population has only 10 individuals and 1 of them dies due to thirst or road/rail accident, the population just lost 10% of the individuals. While if the population has 100 individuals and 1 dies due to one of these random incidents, 1% of the population died.
The random process can be demographic for example if a population had 10 individuals and 1 couldn’t find a mate or failed to produce viable offspring, then only 90% of the population contributed to the next generation. While if the population has 100 individuals and one failed, 99% contributed to the next generation.
There is also genetic stochasticity where an advantageous genetic variant may be randomly lost or a deleterious genetic variant can be randomly fixed in a population. This happens more often in a small population (for example due to above effects) than in large population. This reduces the overall fitness of a population.