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iayork t1_iu3hj9n wrote

Certainly it’s possible, though not inevitable. Small inbred populations can persist in spite of small founder populations - the classic examples are island foxes, and island populations are the best studied.

Populations can survive inbreeding better if they have a longish history of smallish (but not too small) populations. This leads to long periods of low-level inbreeding, and that leads to purging of deleterious genes. In other words, a long period of mild inbreeding can accidentally prepare a population for a shorter period of severe inbreeding.

Moose are actually good candidates for this, because they arose during periods of glaciation, which presumably led to small populations that would alternate periods of inbreeding and then as the ice allowed intermingling and new gene flow.

Is this what actually happened? I don’t know, but the principles are pretty well understood and if your question is could this happen, certainly it could. Since there obviously are moose on Newfoundland, the alternative is denying reality or positing some clandestine moose-smuggling operation, so this is the simplest answer.

Further reading:

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pds314 t1_iu4emak wrote

Keep in mind moose routinely cross water. It isn't totally impossible they can get to Newfoundland from the mainland on their own. The shortest distance between Newfoundland and the mainland is 17.5 km which is not exceptional for the distance moose can swim.

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iayork t1_iu4jnqt wrote

Sure, it’s possible there was outside gene flow (the genetics papers I linked address some of that). But the question is is it possible, not how far can moose swim.

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spiderfarmer t1_iu4glei wrote

Why would a moose do that though?

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DomovoiP t1_iu4kjmi wrote

Moose likes yummy seaweed, swims out some distance to eat some. Crazy current drags the moose out to sea, it gets disoriented. Moose then swims until it Finds a New Land.

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jumpmanzero t1_iu4mqno wrote

And two of them, with a length of seaweed between them, could absolutely bring along a coconut.

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Isotope_Soap t1_iu4t36c wrote

Are you suggesting that coconuts migrate?

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herbdoc2012 t1_iu4uzeq wrote

On the backs of small parrots flying between the fjiords is how coconuts migrate as we all know that!

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DragonBank t1_iu5a683 wrote

The hard part is a female and male both doing this in a period they can viably reproduce and meeting eachother on the islands. I'd assume 100s of moose would need to attempt this before a population occurs.

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PacoTaco321 t1_iu5zfwk wrote

It is a low probability of happening, but species spreading to a completely different part of the world from floating thousands of miles across an ocean and having a viable population in that new area also happened a lot more often than you'd probably think, so two moose swimming on their own 18 km is not too much of a stretch.

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mdielmann t1_iu63iv0 wrote

If a small population was already there, say, introduced by people, every moose that migrated there would be a breeding candidate.

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Ihavebadreddit t1_iu4zofr wrote

A deer swam from NB to PEI recently. 12.9 km roughly

Only to be hit by a truck once it reached the island.

There are no deer in PEI

Well.. there was 1 for a few hours.

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mattdjamieson t1_iu6v1ec wrote

It’s true they send people over Confederation bridge to make sure no deer are sneaking over on the highway. Lol

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GuanoLoopy t1_iu4k3ei wrote

It's not like they are thinking, 'hey let's go for a long swim', but they do go into water to eat and swim and if they got turned around or a current brought them away from land or a storm came upon them, they have no choice but to keep swimming. So some very small percentage could stumble upon it that way. All you need are a couple (or 4) to get a population started, and if some new moose got added to the genepool via a water crossing that would help a genetically bottlenecked population tremendously.

And at first glance 110K from 4 moose seems like a rather large population boom. But they can produce 1-2 offspring per year, so not accounting for deaths and a best case scenario that can grow rather quickly, and if you can sustain 110K moose there are way more resources available than needed for a much smaller population so resource constraints wouldn't be a problem at least. A few decades and some luck is all they needed.

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BigZombieKing t1_iu599d5 wrote

In the rut, a bull moose will come from that distance or more to the call of a cow moose. Plowing through the thickest bush, swimming through anything and just generally ignoring the terrain.

Once there were cow moose across the water, I think bull moose crossing would be inevitable.

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Kaalmimaibi t1_iu44n7f wrote

So European royalty would have been fine if they’d just persisted with consanguineous relationships just a little longer? How extraordinary.

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iayork t1_iu4be82 wrote

European royalty were pretty much the opposite of “a long period of low-level inbreeding”, so no.

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Kaalmimaibi t1_iu4e05b wrote

The data here indicates the predominance were second cousins and it’s been going on for a thousand years. What degree of relatedness and timeframe is necessary then?

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Alis451 t1_iu4o4ta wrote

> second cousins

these aren't actually any inbreeding, second cousins are functionally strangers.

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iayork t1_iu4kjqp wrote

Are you arguing that the royalty of Europe have entirely gone extinct due to inbreeding? Or are you arguing that occasional members showed deleterious recessives, while most (like Charles) have been spared those effects, as you’d see with purging of recessives?

I know you just made a throwaway joke, but if you’re actually going to make an argument of it, you should think through what you’re actually claiming.

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PhilistineAu t1_iu4pjo5 wrote

They would have been fine if they had removed the deleterious genes.

You can be fine if your starting gene population doesn't lead to cascading abnormalities or a high level of disease susceptibility.

If those moose are that genetically close, and they lack sufficient diversity to handle a new disease (or environmental) threat, then you are looking at population collapse. Without that challenge, the population looks fine.

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viridiformica t1_iu4z4yp wrote

There's not much selective pressure on royalty though - rather the opposite

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Cronon33 t1_iu4utzt wrote

Thanks for this insight, I would have assumed at 4 individuals they'd surely be beneath the minimum viable population and destined for inbreeding depression

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iayork t1_iu52lpr wrote

Mostly that’s true. But given the right background, and a significant amount of luck, very small founder populations can expand enormously. This is very common in invasive species. The 200 million starlings in North America today arose from a few dozen in the late 1800s. Bull trout in Montana arose from two founders. A million Barbary Ground Squirrels arose from a single female.

Again, this is possible but not inevitable. Most such introductions will collapse due to inbreeding. But occasionally explosions can happen.

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Cronon33 t1_iu54o2o wrote

Right of course, there is no guarantee either way, at least with breeding individuals

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atomfullerene t1_iub56ki wrote

Minimum viable population is less of a rule and more of a guideline. Specifically speaking, it's usually defined as something like "the minimum population to have a 95% chance of survival for 100 years, in a population that isn't being specifically managed by people."

95% is a pretty high percentage, so there's a lot of "room" below it. Maybe 4 moose only have a (to pull a number out of the air) 25% chance of survival....but that's common enough that it isn't surprising to see it happened.

And furthermore, populations can have big advantages that mean their actual odds of survival are higher than the given percentage. For example, moose introduced onto an island with no competitors and no predators can expect to have a greater fraction of their offspring survive. And that means their population will more rapidly grow out of the danger zone.

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Tempest8008 t1_iu654ty wrote

The Colombian Hippo population is another example. One male and three females were released into the wild less than 40yrs ago and that population is over 70 animals now.

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