Animal Conservation

Using genetics to conserve wildlife

What if we could help endangered wildlife species better adapt to the intractable threats that many species face due to challenges such as climate change and disease?

The United Nations has warned that approximately one million animal and plant species are threatened with extinction. In response, conservation breeding programs are intensifying to stimulate and protect populations.

The problem is that while conservation breeding can prevent extinction, it does not allow endangered species to survive in the wild in the face of these hard-to-mitigate threats.

Climate change and disease are tough threats to species, but genetic technologies could help some species adapt. Photo: Getty Images

So while it’s essential that we tackle climate change and disease, we also urgently need to find a way to make it easier for species to live with the threats.

This is where targeted genetic intervention (TGI) comes in.

TGI works by adapting methods that are used successfully in agriculture and medicine in which an individual’s genetics are altered in such a way that when passed on to the general population through reproduction, it can modify the traits of a species to improve its survival.

Two of the most promising approaches in this toolkit include artificial selection and synthetic biology.

Artificial selection

Artificial selection has been used for thousands of years in animal and plant breeding to produce pets, farm animals, and agricultural crops with desired characteristics.

This led to the development of many animals and plants that we now depend on for food or companionship, such as dairy cows, rice, and Golden Retrievers.

These approaches have even been hailed by English naturalist Charles Darwin for their amazing ability to generate our domestic dogs from wolves – which are as different as Chihuahuas and Great Danes.

Today, advances in genomic approaches have made methods of artificial selection considerably more sophisticated than in Darwin’s time. We can now use genomic information to predict the traits an animal will have with an approach known as genomic selection.

Advances in genomics have made artificial selection, or selective breeding, more sophisticated. Photo: Shutterstock

Genomic selection can be a game-changer for endangered wildlife, as it enables the development of informed selection strategies that promote adaptation.

It works by first understanding and identifying which genetic characteristics make members of a species more suited to an environment or threat than others. This is usually done by exposing individuals from a reference population to the threat (such as heat stress or an infectious disease) and then measuring their response.

We then look for genes present in individuals who resist and survive the threat. This genetic information can be used to predict which animals in the breeding population are best suited to survive a given threat based on their own genotype.

Over time, the use of genomic selection as a reproductive strategy may increase the average survivability of these individuals in the breeding population by promoting adaptation in captivity.

The ability to use this type of genomic prediction data based on discrete groups of individuals is a major advantage because it means that risky activities, such as exposing a population to a disease or other infection in part of a trial, can be carried out separately in laboratories away from critical breeding populations.

Synthetic biology

Synthetic biology is newer and more controversial than artificial selection. It includes methods such as transgenesis and gene editing.

Synthetic biology goes beyond breeding to involve the direct modification of genetic information or the introduction of new information. Photo: Getty Images

While these methods feature frequently in science fiction and are sometimes feared for their unintended consequences, the real science of synthetic biology is gaining traction in the conservation community due to its many benefits.

Additionally, a recent public opinion survey conducted by the Commonwealth Scientific and Industrial Research Organization (CSIRO) indicates that the public is moderately to strongly supportive of the use of synthetic biology approaches for conservation.

Synthetic biology can be used to introduce lost or new genes and modify specific genetic characteristics of an organism without modifying other characteristics, which often happens with less targeted approaches like artificial selection.

Transgenesis does this by incorporating foreign DNA from a different species into the genome. Gene editing is more subtle and works by tricking the organism itself into eliminating or replacing targeted genes.

American chestnuts, corals and black-footed ferrets are just a few of the species for which synthetic biology methods are being tested to aid in restoration. American chestnut trees, in particular, are a great success story for the use of synthetic biology for conservation.

This species was driven to near extinction in North America after the introduction of the Asian Chestnut Blight fungus in the late 1800s.

Synthetic biology is trying to protect the American chestnut (pictured with pollen). Photo: Timothy Van Vliet/Wikimedia Commons

Various approaches have been tested to increase resistance to this pathogen with varying degrees of success, but since the tree lacks natural resistance, the most effective approach to date is to use transgenesis to introduce a new wheat gene. disease tolerant.

This has produced American chestnut trees that seem to tolerate blight. Trial plantings of these trees in US forests may begin soon, pending regulatory approval.

What happens afterwards?

My research group at the University of Melbourne recently received grants from the Australian Research Council (here and here) to test TGI approaches in various Australian frogs vulnerable to extinction.

Many frogs in Australia and around the world are threatened by chytridiomycosis, a devastating fungal disease. This disease is caused by the introduced fungus Batrachochytrium dendrobatidis and unfortunately, few options exist to restore susceptible frogs to this disease in the wild.

We are working with various institutions, including Zoos Victoria and the Taronga Conservation Society, to determine if TGI approaches can be used to increase resistance to chytridiomycosis in Australian frogs.

TGI approaches are explored as options to help conserve endangered frog species. Photo: Getty Images

We are currently working on the iconic Southern Corroboree frog (Pseudophryne substantiated) and, in the next few years, we plan to add other species such as the green frog and the bell frog (Litoria aurea) and the Northern Corroboree Frog (Pseudophryne pengilleyi).

It is imperative that we as a community investigate the application of TGI approaches for conservation, as in some cases they may be the only way to restore a species to the wild.

But with that comes the responsibility of the public, government, and scientists to not only fund TGI research, but also to ensure that it is done responsibly with careful attention to all involved entities and with a proper assessment of all potential risks.

Since TGI for conservation is a new concept, species modified by TGI should be evaluated to ensure that the genetic changes induced increase survival and that the organisms do not pose a risk to the environment by occupying a niche. or a different position in the food chain.

Given the scale and gravity of the challenge of conserving our wildlife, and given the established effectiveness of the TGI, this is an approach we cannot afford to ignore.

The ideas introduced in this article are discussed in more detail in our recent article in the journal Trends in Ecology and Evolution. Dr. Kosch’s co-authors are Anthony W. Waddle, Dr. Caitlin A. Cooper, Professor Kyall R. Zenger, Professor Dorian J. Garrick, Associate Professor Lee Berger, and Professor Lee F. Skerratt.

The genome of the southern corroboree frog is being sequenced for researchers by the Vertebrate Genomes Project.

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