Many beloved species are seeing their numbers decline around the globe. One report says that the population of many beloved species is declining at an increasing rate. grim projection, as many as 40% of the world’s species may be extinct by 2050. Alarmingly, many declines are caused in part by threats that have few solutions.
Many species depend on conservation breeding programs to ensure their survival. These programs are often not encouraging species to adapt and survive in nature, despite the fact that they face many intractable threats like disease and climate change.
This means that some species are no longer possible to find in the wild. This has major downstream consequences for the ecosystem. Imagine how a coral reef without corals would fail to function.
What if there were another way? My colleagues, me and others have developed an intervention technique that gives endangered species the genetic traits they need to survive in nature.
Transforming theory into practice
Natural selection is a process that allows species to adapt over time to new threats. But in many instances today, the speed at which threats are developing is outpacing species’ ability to adapt.
This problem is particularly apparent in wildlife that is at risk from new infectious diseases like chytridiomycosis, which affects amphibians, as well as species affected by climate change such as corals.
The toolkit my colleagues and I developed is called “targeted genetic intervention” or TGI. It works by increasing the occurrence or frequency of genetic features that impact an organism’s fitness in the presence of the threat. In a recent article, we describe the method. Research paper.
The toolkit includes artificial selectionAnd Synthetic biology. These tools are well-established in agriculture and medicine, but have not been extensively tested as conservation tools. We will explain them further below.
Many tools from our TGI toolkit were discussed in theory in conservation literature over recent decades. However, some tools are now practical thanks to rapid advances in genome sequencing and synthetic biology.
It is now easier to understand and manipulate the genetic basis of traits that allow a species adapt to changing environments.
What is artificial Selection?
Artificial (or phenotypic), selection has been used by humans for many years to promote desirable traits in animals and plants that are raised for companionship or food. This genetic alteration has produced organisms like domestic dogs and maize that are dramatically different than their wild progenitors.
Traditional artificial selection can result in outcomes such as high levels of inbreeding that are detrimental to the organism’s health, resilience, and conservation. If you’ve ever owned a purebred dog, you might be aware of some of these genetic disorders.
And when it comes to conservation, determining which individuals from a species are resistant to, say, a deadly pathogen would involve exposing the animal to the threat – clearly not in the interests of species preservation.
A new approach has been developed by scientists in the livestock industry to solve these problems. It is called genomic selection and it combines data from animal studies (such a disease trial) and the genetic information of the animals in order to predict which animals are most likely to adapt.
These individuals are then selected for breeding. Over subsequent generations, a population’s ability to survive alongside pervasive threats increases.
Genomic selection has resulted in disease-resistant salmon and livestock that are more milky and can tolerate heat better. It is still being tested in conservation.
What is synthetic biology?
Synthetic biologyIt is a toolkit that promotes change in organisms. It includes methods like transgenesis and gene editing that can be used to create new genes or modify specific genetic features.
Such tools can accurately tweak targeted genetic features in an individual organism – making it more able to adapt – while leaving the rest of the genome untouched. The genetic modifications can then be passed on to future generations.
This method reduces the chance of unintended genetic modifications that can occur through artificial selection.
For conservation of multiple species, synthetic biology methods around the globe are being studied. These include the Chestnut treeBlack-footed ferretsThe United States has the following: CoralsAustralia
TGI methods for Australian frogs are being developed by me and researchers at the University of Melbourne. These methods are currently being tested in the iconic Southern Corroboree Frog. If they work, we will expand them to other species.
The disease chytridiomycosis, which is a fatal illness in frogs, has decimated frog populations around the world. Fungal pathogens are responsible for the disease. Batrachochytrium dendrobatidisIt has resulted in the extinction of approximately 90 species of frogsYou can also see declines in up to 500 other areas.
Conservation breeding is a key factor in the survival of many frog species. Because the fungus is not eradicable, there is no effective method to restore chytrid susceptible frogs to their natural habitat.
Targeted genetic intervention will likely involve trade-offs, as with many conservation strategies. One example is that genetic features that make a species more resistant to one disease might make it more vulnerable to another.
But the rapid rate of species declines means we should trial such potential solutions before it’s too late. The higher the likelihood of irreversible environmental changes, the longer that species are absent from an eco-system.
All stakeholders should be involved in any genetic intervention of this nature, including Indigenous peoples as well as local communities. You should also be careful to ensure that these species are suitable for release and pose no threat to the environment.
We hope that by bringing TGI to public attention, government scientists, and other scientists, we will encourage discussion and research on its benefits and risks.