Entrepreneur plans to resurrect woolly mammoths(nhm.ac.uk)
nhm.ac.uk
Entrepreneur plans to resurrect woolly mammoths
https://www.nhm.ac.uk/discover/news/2021/september/entrepreneur-plans-to-resurrect-woolly-mammoths.html
96 comments
> Can mammoths really reverse climate change?
It’s so obvious: we should sequester carbon inside of wooly mammoths.
It’s so obvious: we should sequester carbon inside of wooly mammoths.
> > It is argued that the giant herbivores such as mammoths maintained these open grasslands by keeping encroaching forests at bay, and as a result helped cool the planet.
> That seems like pure nonsense and perhaps a way to market their goofy experiment to gullible journalists.
The effect of mammoths can be true AND it can be "a way to market their goofy experiment to gullible journalists". We've seen significant changes caused by the near extinction of the American Bison for instance.
> That seems like pure nonsense and perhaps a way to market their goofy experiment to gullible journalists.
The effect of mammoths can be true AND it can be "a way to market their goofy experiment to gullible journalists". We've seen significant changes caused by the near extinction of the American Bison for instance.
Individual statements here may be true on some level (e.g. 'large mammals maintain grassland', 'steppe climates sequester carbon'), but that doesn't make the broad conclusions true. We can't just rewild the Great Steppe, we grow our food there now!
Anyways, ecosystems are complex. Here in Scotland we have a proliferation of deer, which no longer have any predators except cars and posh men with guns. No new trees with them around. They are also destroying peatlands, which I imagine are a much better carbon sink than grassland.
https://www.theguardian.com/environment/2020/jan/29/huge-ris...
Anyways, ecosystems are complex. Here in Scotland we have a proliferation of deer, which no longer have any predators except cars and posh men with guns. No new trees with them around. They are also destroying peatlands, which I imagine are a much better carbon sink than grassland.
https://www.theguardian.com/environment/2020/jan/29/huge-ris...
Contemporary goats can keep a grassland from becoming forest all too well (by eating the seedlings) and overgrazing can have serious effects [0]. Maybe woolly mammoths played a similar role in Siberia, but being less numerous, did not desertify the region, only kept it open and treeless.
Grass does not have much nutritional content. A beast of the size of a mammoth will have to eat a lot of it to sustain itself.
[0] https://www.climatechangenews.com/2013/09/09/mongolian-stepp...
Grass does not have much nutritional content. A beast of the size of a mammoth will have to eat a lot of it to sustain itself.
[0] https://www.climatechangenews.com/2013/09/09/mongolian-stepp...
Take a look at this experiment in Siberia : https://en.wikipedia.org/wiki/Pleistocene_Park
>The aim of the project is to research the climatic effects of the expected changes in the ecosystem. Here the hypothesis is that the change from tundra to grassland will result in a raised ratio of energy emission to energy absorption of the area, leading to less thawing of permafrost and thereby less emission of greenhouse gases.[8][9] It is also thought that removal of snow by large herbivores will further reduce the permafrost's insulation.
>To study this, large herbivores have been released, and their effect on the local fauna is being monitored. Preliminary results point at the ecologically low-grade tundra biome being converted into a productive grassland biome and at the energy emission of the area being raised.[10]
>The aim of the project is to research the climatic effects of the expected changes in the ecosystem. Here the hypothesis is that the change from tundra to grassland will result in a raised ratio of energy emission to energy absorption of the area, leading to less thawing of permafrost and thereby less emission of greenhouse gases.[8][9] It is also thought that removal of snow by large herbivores will further reduce the permafrost's insulation.
>To study this, large herbivores have been released, and their effect on the local fauna is being monitored. Preliminary results point at the ecologically low-grade tundra biome being converted into a productive grassland biome and at the energy emission of the area being raised.[10]
> That seems like pure nonsense and perhaps a way to market their goofy experiment to gullible journalists.
Grasslands evolved in symbiotic relationships with the animals that tread on them, just as in any other part of the biosphere. As long as the wooly mammoth population is kept in check by humans, since they are not introducing mammoth predators, they will aerate the ground, eat and spread seeds, and provide essential elements and minerals to the soil as a natural part of their excretion processes. It will also have knock-on effects as insects regain access to dung, and that will feed the birds, and the birds and their eggs will become food for other animals, and so on.
It's a lot easier to restore ecology that existed 10-20 thousand years ago than to wait millions of years for another set of species to maximize the biological output of a given area. Rewilding is based on solid science and is thankfully here to stay.
Grasslands evolved in symbiotic relationships with the animals that tread on them, just as in any other part of the biosphere. As long as the wooly mammoth population is kept in check by humans, since they are not introducing mammoth predators, they will aerate the ground, eat and spread seeds, and provide essential elements and minerals to the soil as a natural part of their excretion processes. It will also have knock-on effects as insects regain access to dung, and that will feed the birds, and the birds and their eggs will become food for other animals, and so on.
It's a lot easier to restore ecology that existed 10-20 thousand years ago than to wait millions of years for another set of species to maximize the biological output of a given area. Rewilding is based on solid science and is thankfully here to stay.
lol humans can keep forests at bay! why do we need mammoths for that?
It was literally the basis for Jurassic Park. It's kinda like the fusion meme. Except fusion seems a bit closer than it used to.
I remember reading a cryptozoological theory that there could still be some mammoths left, hidden in the vastness of Siberia. Absurd, obviously, but I always thought you could make a great film about a ragtag crew searching for the last remaining mammoth tribe in the wilderness.
Oh yeah, that theory started with an obviously bogus video.
Actually that idea is intuitively easy to understand once you consider how large Siberia is. It's hard to imagine humans could extinguish any species there, even one that's so hard to miss.
But if course, we don't really know how Mammoths lived, how far they travelled, where and when they bred, etc.
Maybe all humans had to do was wait on some river crossings in a specific time of the year because some instincts told the Mammoths to traverse that route every year before mating season. Or maybe we didn't extinguish Mammoths and they died from some contagion (why should that only happen to humans?).
But if course, we don't really know how Mammoths lived, how far they travelled, where and when they bred, etc.
Maybe all humans had to do was wait on some river crossings in a specific time of the year because some instincts told the Mammoths to traverse that route every year before mating season. Or maybe we didn't extinguish Mammoths and they died from some contagion (why should that only happen to humans?).
One country has a legend of mammoths. One country has Loch Ness monster. Another has sasquatch. Another has yeti. Some even have dragons or sea creatures.
This sounds more like dog breeding with elephants and gene editing than Jurassic Park.
They are trying to make a cold weather adapted elephant
They are trying to make a cold weather adapted elephant
I suppose that begins to ask the question of what it means to be a wooly mammoth.
If it fills the ecological niche of an <X>, and it looks like and has many of the same genes as an <X>, is it not an <X>?
There's a bit of sci-fi fun in Neal Stephenson's wonderful "Seveneves"[0] where people are trying to re-populate the earth with animals after a planet-wide extinction event. They originally tried to make exactly the same wolves and lynx and rabbits and so on, but eventually realized they could just make "big pack dog animal" and "stalking cat animal" to fill the niches and let evolution do the fine tuning for them.
[0]https://en.wikipedia.org/wiki/Seveneves
If it fills the ecological niche of an <X>, and it looks like and has many of the same genes as an <X>, is it not an <X>?
There's a bit of sci-fi fun in Neal Stephenson's wonderful "Seveneves"[0] where people are trying to re-populate the earth with animals after a planet-wide extinction event. They originally tried to make exactly the same wolves and lynx and rabbits and so on, but eventually realized they could just make "big pack dog animal" and "stalking cat animal" to fill the niches and let evolution do the fine tuning for them.
[0]https://en.wikipedia.org/wiki/Seveneves
I have doubts as to the survivability of any 'mammoth' produced. The ancient animals were part of an ecosystem long extinct. Their gut biome for instance is long gone. While they might gestate something and even bring it to term, it could die in days because it can't live in this world without a parent mammoth to donate its biome.
I think this is considerably more difficult than they think, genomes are more than just throwing genes together. It’s a finely tuned symphony made by evolution, epigenetic silencing and signaling, gene position. I suspect it doesn’t work at all but if they got something it would be more like the centaurs in Fallout. I also think there are ethical questions whether that baby “mammoth” being born would ask to be created in that failed way.
https://fallout.fandom.com/wiki/Centaur
https://fallout.fandom.com/wiki/Centaur
Maybe not that difficult. We already have sequenced the mammoth genome [1]. We have CRISPR technology. We can do a diff between the mammoth genome and the elephant one, and we start editing the elephant one small segment at a time, like in a game of word ladder. We IV fertilize an elephant female, and we get a hybrid. After a few steps, we might end up with an actual mammoth.
[1] https://www.scientificamerican.com/article/mammoth-genomes-s...
[1] https://www.scientificamerican.com/article/mammoth-genomes-s...
You only learn how difficult it is by attempting it.
We breed zillions of animals without ever asking them for consent. In part because it's impossible. Those are some brand new goalposts.
We breed zillions of animals without ever asking them for consent. In part because it's impossible. Those are some brand new goalposts.
Evolution constricts those outcomes to something at least somewhat reasonable and capable of life because both parents were able to live.
Trying to resurrect extinct species while we actively try to make the existing ones extinct is absurd.
Actually, it's a good way practicing how to restore those as well. There's less at stake with already extinct species. We've wiped out plenty of species already and we probably have a growing amount of DNA to play with. I take it as a given that there will be a lot more species disappearing over the next decades. So, any early successes with this will be helpful. Once we clean up the planet in a few centuries, we'll be able to restore ecosystems this way potentially. A key thing for that is figuring out how to get genetic diversity to avoid inbreeding becoming a thing.
At a minimum, maybe it’s shit timing to resurrect an animal better for colder weather.
The existing species are lame compared to wooly mammoths and giant centipedes.
This person has the feck of 20 people, lol.
Or par for the course. It's easier to create something than to stop creating something once it has become a thing.
I’ll believe it when I see it. I’ve read before about people claiming they’re going to turn chickens into velociraptors too.
It’s way easier to write a press release than it is to actually do the work. The image of “how to draw an owl”[0] comes to mind.
https://knowyourmeme.com/photos/572078-how-to-draw-an-owl
It’s way easier to write a press release than it is to actually do the work. The image of “how to draw an owl”[0] comes to mind.
https://knowyourmeme.com/photos/572078-how-to-draw-an-owl
Can the modern Arctic environment really support herds of new mammoths? I know they used to roam the tundra 5,000 years ago, but they've been absent since. Wouldn't their reappearance displace the creatures that have taken their place in the ecosystem? Perhaps moose and arctic ox would suffer a decline?
It seems really reckless to me to resurrect long dead creatures and to call that "healing the earth". I don't think these people have the systems in place to model the ecosystem accurately enough to know whether introducing a new hybrid into the environment would be beneficial for any creature on Earth (except themselves of course ... I'm sure they'll have a great Instagram post about it).
It seems really reckless to me to resurrect long dead creatures and to call that "healing the earth". I don't think these people have the systems in place to model the ecosystem accurately enough to know whether introducing a new hybrid into the environment would be beneficial for any creature on Earth (except themselves of course ... I'm sure they'll have a great Instagram post about it).
The most reckless part is resurrecting highly intelligent social creatures.
The problem becomes apparent if we look at African elephants - if the matriarch is killed before passing on her knowledge, the herd often dies or disbands.
Now imagine just popping a small group of mammoths into existence who never roamed the Arctic tundra and expect them to just "know" how to mammoth. It takes many generations to achieve that and given that they can live about as long as humans, I doubt the researchers are really able to help with that.
The problem becomes apparent if we look at African elephants - if the matriarch is killed before passing on her knowledge, the herd often dies or disbands.
Now imagine just popping a small group of mammoths into existence who never roamed the Arctic tundra and expect them to just "know" how to mammoth. It takes many generations to achieve that and given that they can live about as long as humans, I doubt the researchers are really able to help with that.
Definitely brings up images of aliens cloning humans after we've gone extinct, then placing us in groups with food and hoping they recreate human civilization. I think the result would be more sad and pathetic than Lord Of The Flies.
That said, presumably they'd rear the baby mammoths with elephants and at least develop social skills, even if they can't develop environmental skills; and then support the animals as they become used to arctic conditions. But would that just the be the equivalent of raising Neanderthals and then transporting them to the wilderness for their Exciting New Life In The Wild?
That said, presumably they'd rear the baby mammoths with elephants and at least develop social skills, even if they can't develop environmental skills; and then support the animals as they become used to arctic conditions. But would that just the be the equivalent of raising Neanderthals and then transporting them to the wilderness for their Exciting New Life In The Wild?
Ya reminds of the (awesome but at the same time horrific) post apocalyptic film Threads: https://m.imdb.com/title/tt0090163/?fc=2&ft=29&fm=1
Mammoth, a novel by John Varley
https://en.wikipedia.org/wiki/Mammoth_(novel)
Highly recommend.
I think this is doable. It will take time, however they have an increasing number of frozen mammoths, and even more mammoth tusks (I do not know if the tusk has a 'root' as a tooth does. By sequencing all these sources they have a good shot at crafting the full genome. As a mammal, the closely related species of elephant they have found should be able to provide viable eggs that can be renucleated with mammoth DNA based starters with the correct initiators to render them viable. They have the ability to make the eggs in the lab, fertilize them and see how they progress through numbers of divisions. Once they reach that point, they can try implantation, or even artificial wombs that has been done for mice - will it scale?
Their timeline of ~~6 years also seems viable, and it may be faster or slower.
Man has caused many extinctions, they say mammoths are one of them - perhaps others we extincted can be saved as well, if suitable source material can be found, such as earlier races of man that might be as good or better than man?
I am amazed that the bio establishment does/has not do/done/tried this - leaving it to entrepreneurs?
What’s the line from Jurassic Park? “They were so preoccupied with whether or not they could, they didn’t stop to think if they should”
Why do the dinosaurs always escape in Jurassic Park? Is it because the mathematics of chaos theory dictate that life always finds a way? Or is it because nobody pays to see a movie where a couple of brats go on an uneventful vacation to a dinosaur zoo?
It's definitely the latter, but through the power of repetition people started to believe it was the former.
It's definitely the latter, but through the power of repetition people started to believe it was the former.
Neither. It's because it's extremely difficult to keep large animals confined indefinitely through all circumstances. Ask any farmer with livestock. The bigger they are, the more capable they are of ignoring whatever fencing/obstacles you put in the way.
Zoos keep Rhinos. They manage without the kind of budget that a resurrected dinosaur would afford. They also keep elephants, 800lb gorillas, chimps, ostriches, all kinds of powerful and intelligent beasts capable of reproduction. They sometimes escape, but it's the exception, and killing the animal(s) is always a last-ditch option.
That last point is another place where I expect a huge fiction-reality gap. If I pay to watch a movie about a dinosaur getting loose, I want to see it shrug off bunker-busting missiles from fighter jets, with big fireball explosions and people jumping in the air and the hero magically surviving. I don't want to see a short, sad walk down to the city park where they try and fail for an hour to coax it back and ultimately decide that they have to shoot it with a slightly larger than average rifle. That's the boring and horrible but realistic scenario.
There's nothing wrong with the movie scene not being realistic, but there is something wrong with blindly assuming that the movie scene is realistic.
That last point is another place where I expect a huge fiction-reality gap. If I pay to watch a movie about a dinosaur getting loose, I want to see it shrug off bunker-busting missiles from fighter jets, with big fireball explosions and people jumping in the air and the hero magically surviving. I don't want to see a short, sad walk down to the city park where they try and fail for an hour to coax it back and ultimately decide that they have to shoot it with a slightly larger than average rifle. That's the boring and horrible but realistic scenario.
There's nothing wrong with the movie scene not being realistic, but there is something wrong with blindly assuming that the movie scene is realistic.
> They sometimes escape, but it's the exception
That's... kinda my point!
Zoos keep large animals in significantly smaller areas that are easier to control and maintain. I can see someone making "Jurassic Zoo" where you're keeping a few fairly docile dinosaurs in an area of a few acres. I don't have hard data but the territories in Jurassic Park look like they were measured in square miles.
That's... kinda my point!
Zoos keep large animals in significantly smaller areas that are easier to control and maintain. I can see someone making "Jurassic Zoo" where you're keeping a few fairly docile dinosaurs in an area of a few acres. I don't have hard data but the territories in Jurassic Park look like they were measured in square miles.
If "escapes are rare and low-consequence" is your point, I'm happy to agree.
Re: enclosure size, that's because city land is expensive, not because the mathematics of chaos theory dictate that it is impossible to hold an animal in a large enclosure. Come on.
Re: enclosure size, that's because city land is expensive, not because the mathematics of chaos theory dictate that it is impossible to hold an animal in a large enclosure. Come on.
It's because the scriptwriters tried selling a script where nothing much happened, and didn't even get past the receptionist.
Nobody likes "Billy and the Clonosaurus".[0]
0: https://www.youtube.com/watch?v=wIUh-MHsQKU
0: https://www.youtube.com/watch?v=wIUh-MHsQKU
Isn't it almost always that the safeguards in place are poor? Either poorly maintained or the caretakers don't care at all.
Jurassic Park is a great example of hard scifi in that the problems which happen all happen in believable ways.
It's still fiction and not an attempt to realistically estimate the rate at which problems would happen or the magnitude of those problems if they did. Look to zoos if you want a realistic point of comparison for the risk analysis -- but not if you want to watch a T-Rex chase kids in Jeeps.
It's still fiction and not an attempt to realistically estimate the rate at which problems would happen or the magnitude of those problems if they did. Look to zoos if you want a realistic point of comparison for the risk analysis -- but not if you want to watch a T-Rex chase kids in Jeeps.
Yep. I was actually thinking of zoos as a counterpoint to my post upthread. But the difference is that of scale: how do you allow a T-Rex or a herd of brachiosaurs the square miles they need for their territory and still keep them within that territory? You may as well just say, "let's not bother fencing them in and just use the ocean itself as the barrier."
There's also “If The Pirates Of The Caribbean Breaks Down, The Pirates Don’t Eat The Tourists.”
No, hold on. This isn't this isn't some species that was obliterated by deforestation or or the building of a dam. Dinosaurs ah ah had their shot, and Nature selected them for extinction.
I thought this was more applicable.
I thought this was more applicable.
If you could make jurassic park with actual zoo architecture and technology that would be pretty cool.
But we all want Jurassic Park though. And we likely will get it in the next few decades, just like we will likely also get Westworld park full of virtual beings that you can seduce (and we probably have something near equivalent in VR now.)
I really doubt people want to seduce sexbots in a public park. If we get realistic west world sexbots, expect them to follow the business model of hookers.
>I really doubt people want to seduce sexbots in a public park
Have you watched the show? It's "public", but it's so huge that the guest concentration closer to rural town than disney world.
Have you watched the show? It's "public", but it's so huge that the guest concentration closer to rural town than disney world.
I watched the original, which was awesome. Newer one didn't appeal to me.
It's a cute idea but that would be stupidly expensive. It would be difficult to compete with the nearby hotel that includes 10 robo-whores complementary with each night at 1/100th of the price; or a giga-chad sex machine that you can just purchase for home use. For sex, or, actually, just as a worker to do real labor because that's a hugely valuable task to society rather than playing pretend saloon whore for a few billionaires.
It's a cute idea but that would be stupidly expensive. It would be difficult to compete with the nearby hotel that includes 10 robo-whores complementary with each night at 1/100th of the price; or a giga-chad sex machine that you can just purchase for home use. For sex, or, actually, just as a worker to do real labor because that's a hugely valuable task to society rather than playing pretend saloon whore for a few billionaires.
I think you've summed up the biggest immersion breaker in that program for me. At some point a character mentions a cost of $40,000/day, which seems like a huge amount until you look at how much staff is needed to keep the park running (including apparently an entire private army), and the amount of damage done on a daily basis which then needs fixing.
That's pretty funny. Strictly speaking, there has to be more robots than people in the park at any time. Probably by a factor of 10-20 or so if you want people to feel like the real people tourists are a small minority. Implying each robot is earning about $2,000-4,000/day. Ignoring the fact that they get destroyed and other fixed costs, it would take years to pay these things off assuming they cost upwards of $10M each.
>which seems like a huge amount until you look at how much staff is needed to keep the park running (including apparently an entire private army), and the amount of damage done on a daily basis which then needs fixing.
[Spoiler]
They did mention that the real money maker for the park was information collection, not the admission fees.
[Spoiler]
They did mention that the real money maker for the park was information collection, not the admission fees.
What information could they possibly be collecting?
excerpt from wikipedia synopsis:
>Arnold organizes a demonstration of the hosts to convince Logan to invest in Westworld. Logan's father, James Delos, is critical of his son's actions until William persuades him that the park can be used to spy on the guests. James proceeds to buy out the park and name William as his successor.
>Arnold organizes a demonstration of the hosts to convince Logan to invest in Westworld. Logan's father, James Delos, is critical of his son's actions until William persuades him that the park can be used to spy on the guests. James proceeds to buy out the park and name William as his successor.
Not really clear to me how spying on someone's sexbot vacation is a viable business model but ok.
That was coincidentally about the point I lost interest the series as it totally jumped the shark from “flawed but I can suspend disbelief” to “oh great, another series that’s going to build ever more tenuous conspiracy theories”.
Oh ok, that's not weird then.
What would be the business model for such a company?
This is what concerns me when I see entrepreneur in the title. I assume the business model would involve encaging them in zoos, hunting them in safaris, or slaughter them to produce exotic food and derived products.
Bringing back an extinct species in order to exploit it.
Bringing back an extinct species in order to exploit it.
My guess is, based on what we think of mammoth, it is a proof of concept that doesn't involve an animal that invokes ideas of Jurassic Park.
> Is returning mammoths to the wild a viable solution to climate change?
No. I can say this unequivocally. What a stupid question.
No. I can say this unequivocally. What a stupid question.
[deleted]
I vote we bring back the Thylacine (AKA Tasmanian Tiger). Such a wondrously unique animal.
https://en.wikipedia.org/wiki/Thylacine
https://en.wikipedia.org/wiki/Thylacine
Mammoth is literally the hardest animal to do this for. Why not the dodo? Or anything smaller/with a faster generation time. I guess that wouldn't bring in investors and reporters...
It has a super long generation time, but at least we have a very large number of carcasses to work from. There's nearly no dodo DNA laying around.
[deleted]
I’m up for bringing back the dodo: at least we reverse the damage we’ve done that way
We have much more experience cloning mammals than birds.
who wants to eat a dodo? no thanks.
apparently a lot of sailors because that's how they went extinct
They're extinct precisely because they were very, very tasty.
Probably more like edible and very easy to catch and kill.
A favorite spot of mariners for a century, because of the taste.
Gee, what could possibly go wrong?
Given our long string of eco system manipulation success stories I mean...
And this time we're not even limited to existing species, exciting times indeed.
Given our long string of eco system manipulation success stories I mean...
And this time we're not even limited to existing species, exciting times indeed.
I hope that he will donate some to the Pleistocene Park.
For the purpose of climate change I believe it would be enough to breed elephants that adapt well to could climates and populate the area with them.
15 million USD for this is laughably little.
They were so concerned with whether or not they could, they never stopped to think if they should.
Because we can definitely fix things better than evolution can.
Have they completely sequenced & assembled their DNA?
Sequenced yes, assembled, no.
Since there's no complete DNA of an individual specimen available, it's impossible to recreate an actual mammoth.
What they're hoping to do is basically isolate the genes that give certain traits (esp. cold adaptation, e.g. fur) and add them to the genome of Asian elephants.
So all they can get - best case - is some sort of mammoth/Asian elephant hybrid.
Since there's no complete DNA of an individual specimen available, it's impossible to recreate an actual mammoth.
What they're hoping to do is basically isolate the genes that give certain traits (esp. cold adaptation, e.g. fur) and add them to the genome of Asian elephants.
So all they can get - best case - is some sort of mammoth/Asian elephant hybrid.
Can't the genome be assembled by aligning the reads against these Asian elephants?
WHGs next.
If the "entrepreneur" starts to beg for money after they have a mammoth ready; great! Otherwise this looks like another tech scam.
> Can mammoths really reverse climate change?
> Colossal say that they want to 'rewild extinct species to their original habitats so they can revitalize lost ecosystems for a healthier planet'.
> It is claimed that woolly mammoths will help to fight climate change by restoring the vast grassland steppes which once encircled the Arctic pole but which changed to forest when the mammoth went extinct.
> 'One of the benefits of grasslands over tundra or forests in the high Arctic is they are really good carbon sinks,' explains Victoria. 'During the summer months the grasses grow high before dying back in the winter. But because of the cold temperature, they don't degrade. Every season's growth is stored in the ground. That is why the permafrost is a massive carbon sink.'
> It is argued that the giant herbivores such as mammoths maintained these open grasslands by keeping encroaching forests at bay, and as a result helped cool the planet.
That seems like pure nonsense and perhaps a way to market their goofy experiment to gullible journalists.