CSIRO investigates gene war strategy to rub out feral cats

[Flaviemys purvisi]

May 26, 2018

By GREG BEARUP


Australian Wildlife Conservancy CEO Atticus Fleming on Newhaven station about 350km northwest of Alice Springs. Picture: Amos Aikman.


In a move that has excited some conservationists, and horrified others, the CSIRO is to investigate the use of genetically modified cats to eradicate Australia’s marauding feral cat population.

The science body recently signed an agreement with conservation group Australian Wildlife Conservancy to begin research that could see gene-drive technology deployed on feral cats.

“Feral cats are killing millions of native birds, millions of our reptiles and millions of mammals every single day,” said AWC chief executive Atticus Fleming.

“This has to be the highest priority for conservation in Australia as nothing causes more damage to native fauna than feral cats.”

Apart from fencing endangered mammals off in feral-free nature reserves, developing gene drive to combat feral cats “is the only glimmer of hope” many native mammals have in being saved from extinction, he said.

The theory behind the project is to genetically engineer cats that produce only male offspring.

These cats would be released across the continent and within a number of generations this gene would spread throughout the population and feral cats would breed themselves out of existence.

It would not affect domestic cats unless they bred with feral cats that had the gene.

The technology, if successful, could also be deployed on invasive pests such as cane toads, carp, rabbits and foxes.

Bill Gates has spent tens of millions of dollars on developing gene drive in mosquitoes in his bid to eradicate malaria.

It has been proven in laboratory conditions on the insects but has not been released in the environment.

Owain Edwards, the head of environmental and synthetic genomics at the CSIRO who will oversee the research, told The Weekend Australian that work had already begun on developing the technology in rodents but it would be years before research was advanced enough to move on to cats.

Then there is the issue of regulatory approval and community acceptance.

There is great resistance among some to all things genetically modified and millions of cat lovers the world over would oppose its release.

Former Greens leader Bob Brown said while he was fully aware of the immense damage cats caused to our native species, he was urging caution. “When it comes to the CSIRO, aren’t they the folk who introduced the cane toads?” Dr Brown said.

“Scientists don’t have any greater grasp on ethics than anybody else. Steady on, ladies and gentlemen — let’s have a public debate.”

He said if the gene spread to the northern hemisphere and into its native cat populations, it could devastate those wild species. “It would be a wonderful thing to be rid of feral cats and foxes,” he said. “But despite the huge prize that is dangling, we need to have the necessary safeguards in place.”

Dr Edwards agreed there needed to be a rigorous public debate before genetically modified cats were released in the wild.

While research had begun on gene drive in rodents, it would be several years before they could even contemplate studying the technology in cats, he said.

“It is very exciting,” Dr Edwards said, “but it is very much a long-term strategy … we’re not saying that this can happen quickly.”

Under the agreement signed with AWC, the conservation organisation is required to rustle up the funding for the CSIRO to take the research from rodents to cats.

AWC is planning a major fundraising effort to get the community involved in the project.

“We will be asking everyone from mums and dads to philanthropists to support this,” Mr Fleming said.

“We know that if they do, it will put pressure on the government to co-invest.”

 

[Fall guys]

Using predators to hunt a predator which will then become the predator? Or am I missing something

 

[Flaviemys purvisi]

Using predators to hunt a predator which will then become the predator? Or am I missing something

NO predators, they want the invasive non native predators to breed themselves into extinction by genetically modifying them.

 

[Fall guys]

NO predators, they want the invasive non native predators to breed themselves into extinction by genetically modifying them.

I misread it, I thought it said they were going to use genetically modified cats to eradicate feral cats

 

[cris]

It seems like a good idea, makes much more sense than spending money on killing 2 million cats or whatever the government did recently or having to resort to fencing everything. If Bob Brown is against it that is almost a 100% guarantee it is a good idea lol.

 

[Flaviemys purvisi]

I personally think it's our ONLY real option.

 

[Sdaji]

I've been wanting to see this used on cats, carp, toads, foxes etc for years. The only concern in species like cats, toads and carp is that it could somehow escape Australia and find its way into natural populations. All the other nonsense is just stupid noise people shouldn't give a minute of thought to. For this reason it would be completely inappropriate for bird species, and it's unfortunately too risky for rats and mice in my opinion. Rabbits are about as far as I'd be willing to go in terms of risk (extremely unlikely that a rabbit would somehow accidentally make its way from Australia all the way to Europe and find a local mate to breed with).

The good thing about it is that once released it quickly wipes the population and itself out, so risk of escape is minimal, unlike a virus/pathogen or predator, parasite etc which reduces the population as a management strategy. It's not realistically possible for the daughterless mutation to exist long term.

Anyone who tries to turn this into any sort of a debate beyond examining the risks of it getting into a natural (native) population is either far too ignorant to deserve a say (but still should be very much welcome to discuss it and learn) or deliberately trying to muddle the discussion for political motives.

 

[Wally]

Sounds like a good idea.. .

What about all the other issues that are placing enormous pressure on ecosystems throughout our nation?

Land clearing for urban sprawl comes to mind.

Cats are bastards, but they aren't the only problem.

 

[Sdaji]

Sounds like a good idea.. .

What about all the other issues that are placing enormous pressure on ecosystems throughout our nation?

Land clearing for urban sprawl comes to mind.

Cats are bastards, but they aren't the only problem.

If every time someone addressed a problem everyone just pointed out that it isn't the only problem in the world, no problem would ever be addressed.

This is a serious issue, something can be done about it, something should be done about it, people should support solutions not pretend the problem shouldn't be solved just because other problems exist.

It is possible in a world with billions of people for multiple problems to be addressed at the same time. No one whinged saying "Oh, but what about cancer?" when someone came up with the first successful heart transplant and they weren't whinging about liver failure while the technology was being developed. This thread is about directly addressing feral species. Land clearing is an important but separate issue.

 

[Wally]

Unfortunately some of the other problems are far easier to address but we continue to look the other way.

Good luck to the CSIRO and the millions that will have been spent to get their genetically modified cats.

 

[Sdaji]

Unfortunately some of the other problems are far easier to address but we continue to look the other way.

Good luck to the CSIRO and the millions that will have been spent to get their genetically modified cats.

Actually, land clearing is not far easier to address than feral cats and would require a complete restructuring of the human population of the continent, including a complete cessation of net immigration and likely a forced deportation of a significant number of Australia's human inhabitants.

Without doing too much research on the subject, my knowledge of genetics (as a geneticist) tells me that genetically modifying cats to create a daughterless form is a lot easier and cheaper than a radical change on the human occupation of Australia. I may not have any formal qualifications or work experience relevant to human population management, but I am quite confident in my assessment as a layman!

 

[cris]

Actually, land clearing is not far easier to address than feral cats and would require a complete restructuring of the human population of the continent, including a complete cessation of net immigration and likely a forced deportation of a significant number of Australia's human inhabitants.

There are ways to increase habitat and reduce land clearing. The Qld government practically banned the use of 1.7 million ha of existing farmland without compensation. While comparable to the actions of a communist dictatorship (and poorly considered) it will increase habitat with very little effort or cost.

There are lots of people who want to stop net immigration and even some sort of deportation, it has more than just environmental benefits. The problem is politicians are to corrupt to touch the subject.

 

[Sdaji]

I would also advocate a zero population increase policy for multiple reasons, but, I absolutely positively guarantee that making such a thing happen would be a far, far greater task than creating and releasing daughterless cats. It's not in Australia's economic best interests, it's politically incorrect, and it's outright unpopular, and even if you could change that or mitigate those issues, yep, you'd also need to deal with corruption. These are all insurmountable obstacles, while the cat project is actually completely plausible and achievable.

You can cherry pick habitat restoration cases, but in the big picture, we both know habitat is being destroyed and that can't change because of the above issues. You're just being obtuse. Habitat is being destroyed faster than it is being created. You know that. Changing that is almost impossible and you aren't going to kid yourself into thinking that in the foreseeable future we might see a net reversal of habitat loss any more than I am. You also won't kid yourself any more than I would about the gross amount of habitat restoration being more than a tiny percentage of total habitat loss.

 

[cris]

I'm not being obtuse, I agree that the GM cat solution should be pushed ASAP and that these other things are much more difficult issues to deal with. I just don't think issues of Australian population and habitat protection are in the impossible category.

I can't find data on the amount of land being cleared for urban development in Qld, but I doubt it is close to 1.7 million ha. While many of the areas effectively stolen from farmers are typically not as valuable as coastal areas used for urban development it probably is still a considerable increase in habitat. This was very cheap and easy to do as practically nobody losing property rights voted Labor to start with.

 

[Bluetongue1]

There are now an estimated 2.7 million domestic cats and over 18 million feral cats in Australia. Australia’s human population is 24.7 million.

Bob Brown is correct. This is not the simple, straightforward ‘silver bullet’ it may initially seems to be. It does require through looking at from all aspects (his suggestion of a public debate). Following are a few things that spring to my mind…

The gene is ultimately self-exterminating, but how long will it be around? Clearly, for the length of time it is present, it does need to be confined to Australia. Is that possible and practical to achieve? When you think about our northern coast line, is there any potential for illegal visitors to those shores taking the gene away with them to SA Asia and its population of moggies. And could this pose a realistic threat to the many small cat species found there?

How do you effectively exclude the gene from domestic populations given the number of cat owners and how many of them are very laissez-faire with their pets. Surely it would require 24/7 containment of all domestic cats? Given there are an estimated 2.7 million domesticated cats in a population of 24.7 million people, that will be a massive social change in itself. What about people moving overseas and wishing to take pet cats with them? Even if you ban emigrants taking cats with them, how much risk is there that those with money will find a fund a way to get around this? Given the potential for domestic cats to be dumped or escape, despite legislation, will this mean it will have to be a continuous process of releasing genetically altered Toms?

Populations of animals can become reduced in usual habitat and consequently temporarily isolated for varying amounts of time, depending the prevailing weather conditions. How are these potential seed populations to be discovered and dealt with?

How effective is it likely to be and how long will it take? Let’s assume that in a given release area, female cats are just as likely to mate with non-genetically altered males ®as they are with released genetically altered (GA) males. This would require the survival after release of the same number of GA males as normal toms in the area. One can expect the kittens produced from this to be 50% GA males, 25% normal males and 25% normal females i.e. 2:1 GA to Normal males. For the next generation the kittens produced would be expected to be 2:½ GA to normal males. Basically the number of normal males in the population is halved with each succeeding generation. So it goes 1 Þ ½ Þ ¼ Þ 1/8 Þ 1/16 Þ 1/32 Þ 1/64 Þ 1/128 Þ 1/256 Þ 1/512 Þ 1/1024. In other words, given that On feral cats have an average life expectancy of about 2 years, it would take 20 years to reduce the feral population to thousands instead of millions. However this would require the release of in excess of 5 million GA males Australia wide. On the positive side, the reduction of female numbers would affect recruitment and increase the rate of population decline. Realistically I would imagine you would be looking at a 50 year plus once it was implemented which may never be able to achieve 100% eradication Australia wide. Perhaps in conjunction with the current developing of baits such as EradicatÒ, CuriosityÒ and HisstoryÒ this may be possible.

No doubt there are plenty more things that need to be considered. Any ideas?

Edit: Corrected typo of Australia's popultion size

 

[cris]

There are now an estimated 2.7 million domestic cats and over 18 million feral cats in Australia. Australia’s human population is 2.47 million.

Bob Brown is correct.
No doubt there are plenty more things that need to be considered. Any ideas?

Bob Brown is not correct he is talking about emotional issues and asking for a public ethics debate. All that is required is a scientific debate. This is not a new idea anymore, as Sdaji points out the risks with some species are extremely low.

It is not the sort of thing where one cat is going to just wipe out all cats. It would be used in combination with other control and prevent the population from constantly bouncing back.

Outside of intentional human misuse the threat is practically non existent. What areas have the same species that is endangered and how will they get there? Why would someone take the cats there?

It doesn't matter how long it takes, complete elimination is not even required. It is a tool that would be highly effective in controlling cats.

The technical aspects of implementation are going to be complex. This is not suitable for a public ethics debate either.

 

[saximus]

@Bluetongue1, I'm a little confused by some of your post; could you help me to understand?

You said the human population is 2.47M but that's an entire order of magnitude too low?

Also, your final numbers seem to be based on a Mendellian recessive mode of inheritance. Is that how these sort of things work? I'd have thought an animal modified in this way would only ever be capable of donating a Y chromosome, thus produce all males, all of the time, not increase the chances of producing them?

 

[cris]

@Bluetongue1, I'm a little confused by some of your post; could you help me to understand?

You said the human population is 2.47M but that's an entire order of magnitude too low?

Also, your final numbers seem to be based on a Mendellian recessive mode of inheritance. Is that how these sort of things work? I'd have thought an animal modified in this way would only ever be capable of donating a Y chromosome, thus produce all males, all of the time, not increase the chances of producing them?

The population is a simpletypo/mistake. The other part of the question really oversimplifies things and is the type of thing you can only start to model when the genetics of the cat is known. These days it should be possible to model with reasonable accuracy how the cats will function once introduced, it will not be something you can do on the back of an envelope.

 

[Bluetongue1]

Typos now corrected thanks guys.

What I did with the figures was only meant to demonstrate this will be no quick fix. We don’t even know how the genetically altered (GA) genome for cats would be introduced. Simply releasing (GA) males may result in loss of most of them, as they have to compete with an established population that is familiar with that environment and know already how to survive in it.

Female cats will mate with multiple males while in oestrus and that would serve to further dilute the input of GA males. They may capture females and mate them with only GA males and then release them once they are no longer receptive. That would be effective but a hell of a lot work. Who knows what they intend to do?

@saximus. GA males produce only GA male offspring. A normal male produces 50% normal male and 50% females. If there is an equal chance of mating with a normal male and with a GA male then the expected will 50% GA males and 25% normal males i.e. 2 to 1. In the second generation, there is 2/3 chance of mating with a GA male and a 1/3 chance of mating with a normal male. The male offspring expected from this would be 2/3 x 1 = 2/3 = 4/6 GA males and 1/3 x ½ = 1/6 normal males. So the ratio of GA to normal males now becomes 4 to 1. At each next generation the number of DA males doubles in relation to the number normal males. It is not determined using Mendel’s notion of Dominant and Recessive traits but it does make use of the expected ratios applied to whole chromosomes. So is it an example of Mendelian genetics? I'd say no but it is certainly based on Mendel's work.

As with humans, female cats have XX sex chromosomes and males have XY. I don’t know for certain but it seems logical to expect that the GA is carried on the Y chromosomes and has the effect of suppressing production of X chromosome gametes somehow.

 

[cris]

Typos now corrected thanks guys.

What I did with the figures was only meant to demonstrate this will be no quick fix. We don’t even know how the genetically altered (GA) genome for cats would be introduced. Simply releasing (GA) males may result in loss of most of them, as they have to compete with an established population that is familiar with that environment and know already how to survive in it.

Female cats will mate with multiple males while in oestrus and that would serve to further dilute the input of GA males. They may capture females and mate them with only GA males and then release them once they are no longer receptive. That would be effective but a hell of a lot work. Who knows what they intend to do?

@saximus. GA males produce only GA male offspring. A normal male produces 50% normal male and 50% females. If there is an equal chance of mating with a normal male and with a GA male then the expected will 50% GA males and 25% normal males i.e. 2 to 1. In the second generation, there is 2/3 chance of mating with a GA male and a 1/3 chance of mating with a normal male. The male offspring expected from this would be 2/3 x 1 = 2/3 = 4/6 GA males and 1/3 x ½ = 1/6 normal males. So the ratio of GA to normal males now becomes 4 to 1. At each next generation the number of DA males doubles in relation to the number normal males. It is not determined using Mendel’s notion of Dominant and Recessive traits but it does make use of the expected ratios applied to whole chromosomes. So is it an example of Mendelian genetics? I'd say no but it is certainly based on Mendel's work.

As with humans, female cats have XX sex chromosomes and males have XY. I don’t know for certain but it seems logical to expect that the GA is carried on the Y chromosomes and has the effect of suppressing production of X chromosome gametes somehow.

I like that you are thinking about this. Your maths are back of an envelope level stuff and do not take into account the potential of modern GM cats, it is not likely to be accurate in the final solution.