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[mainiac]

Just musing on the nature of what a genetic bottleneck in a technologically adept species would do and it occurred to me the results seem rather akin to the societies of space orcs that appear in various science fiction universes (i.e. space orkz, klingons, krogan, etc.) that are common in sci-fi.  It seemed rather interesting to me as the space orcs phenomena is quite common but I dont think they are ever attributed to genetic bottlenecks.

After the initial genetic bottleneck, you would probably see a rapid population boom.  A technological species with a lot of space to grow in is going to grow quite quickly.  Even if the environment is rather hostile such as after a nuclear war, all that space plus all the salvage from the pre-bottleneck society is going to make a society that can easily sustain an initial population boom lasting for a few generations.  After a few generations, you are going to have signifigant inbreeding throughout the entire population.  Assuming a high survival rate, this occurs after log_s_(n) generations where g is the number of sexual partners involved in reproduction and n is the bottleneck population.  What happens next is interesting.

The population at this point isn't just going to suffer from inbreeding, they are going to suffer from vicious inbreeding the equivalent of siblings breeding for many generations.  A whole host of genetic abnormalities that were previously uncommon will become commonplace almost immediately.  There will be huge numbers of unviable offspring and every single offspring is going to suffer from some significant condition or other.  But interestingly is the way this will happen.  Firstly, it will happen very suddenly, in the space of a few generations the population will go from being free of inbreeding to inbreeding being ubiquitous as the number of non-familial breeding partners dries up.  And secondly, they are going to see this coming.  The species is going to have to make a choice at some point, either voluntary extinction or choosing to give birth to children with extreme genetic weakness, knowing what horrors they would be infliction on those children.

Under these circumstances, a sentient race that was previously quite civilized could develop very dehumanizing society.  Parents would be unable to grow overly attached to any of their children, but they would need to covetously protect even the most sickly members of their genetic legacy.  After all, even a weakling caries genetic material that needs to be preserved.  There would be a strong pressure towards very large families to preserve as much genetic legacy as possible.  And every generation would need to make the same dehumanizing choice to inflict misery on the next generation.  Children are no longer a family, they are an investment, and the more children you have and the more sexual partners you have them with, the better your investment in your races genetic future.

Eventually, a very, very vicious species is going to emerge.  By their own standards they are going to be ugly and malformed.  They are going to be brutalized by their upbringing.  But the fact that they are still around means that they are going to set a very high premium on their races survival and a very low premium on treating individuals well. 

The genetic variations have interesting implications as well, some will be born strong and mentally incompetant, some born physically deficient and mentally normal, naturally lending themselves to extreme social stratification.  Those who do poorly on both counts would be like an underclass, but it's important to keep some alive for their genetic legacy.  A few each generation might do well on both counts and rule over the others like divine kings.

Technological progress doesn't need to stop under these conditions, but it could be slowed.  A society that brutalizes itself doesn't take care of it's citizens.  That's why the romans never used steam engines, slaves were so plentiful.  If the ruling class has a huge supply of inferior underlings, they don't need technological progress in the same sense.  But at the same time there is a caste of mentally competant individuals and they could be put to worth keeping track of what technology there is and occasionally improving it.

So over time a viable, but brutal species would emerge.  They would have a very low premium on the individual, strong social pressures to reproduce, be used to brutality and would be technologically stagnant.  Basically, in a nutshell, you have space orcs.  And imagine how they would react to discovering another sentient species with a diverse genetic pool.  All of this is pretty speculative of course and could play out other ways, but it's interesting to think about.

[Karnewarrior]

Interesting. It makes good sense.

Space orcs could also hail from what is simply a brutal planet. Maybe they have many, many children, and the majority of those children won't survive. I always liked the idea that the young cannibalize eatch other and the adults just let them be, until some point in their life where they begin to teach them.

Because for technological progress to be made the species must have some means and a will to teach others to ensure their survival as well. Especially the young. A sentient species is almost required to pass information onto their young in some way.

But this is pure awesome.

[Vattic]

Interesting OP.

I'm going to show my lack of knowledge and understanding in asking this but isn't it possible to recover from a genetic bottleneck? I was under the impression that it's happened to us Homo sapiens at least once.

[Virex]

I don't get how you get so much inbreeding though? Are we assuming a population coming from maybe 2 or 3 parents? In that case, the most inbreeding would be found in the second generation, the point at which there is literally no choice but to get it on with a family member. Also remember that the minimum amount of people for a healthy genetic diversity is roughly 500, probably less. So the bottleneck has to be very significant. Still, at that point, defects are not the problem, since recessive defects only become a problem if a significant part of the founding population has it. The real problem is susceptibility to diseases and a lack of resilience to changing circumstances.

[ed boy]

You are discussing this in the frame of a 'technologically adept species', so I would like to point out a potential flaw in the logic (though it depends just how advanced a community you are thinking of).

I would argue that you are not fully considering the remifications of reproductive technology. If the society is sufficiently advances, I could easily imagine that artificial reproduction would become a significant, if not popular, method of reproduction. If the technology is sufficiently advanced, then the controlled conditions of artificial reproduction would be superior to conventional reproduction, and thus I could see it becoming popular.

This is not wild guessing about fantastical hypothetical technologies. We already possess the ability to fertilize an egg cell outside the human body, and I could easily believe technology to provide a situation in which it can develop to appear within my lifetime.

This would allow a human population to expand very rapidly, as one couple could develop a huge number of children simultaneously. Furthermore, genetic diversity could be cultivated by choosing cells with the most variation to use for the fertlization process, or if technology allows, introducing new variations.

[Karnewarrior]

Interesting OP.

I'm going to show my lack of knowledge and understanding in asking this but isn't it possible to recover from a genetic bottleneck? I was under the impression that it's happened to us Homo sapiens at least once.

I think it depends on the size. It certainly gives Evolution a fast-forward button, so the species that emerges may not be the same as the species that went in.

[UltraValican]

This thread is revelent to my love of orcs/goblinoids.
Orkz fit the bill perfectly.
IIRC corectly 40k orks reproduce through spores, like dorfs( they are realeased through out their lives and in death) Most species that reproduce asexually don't suffer from inbreeding( Im not a scientist so feel free to correct me).
Since orks produce so many spores, it could be impossible to find the "parent" among what could be thousands of spore cases.  I doubt they would care much anyway, since ork "religion" states that you just get belched back into a new ork when you die.
Due to their rapid  rate of reproduction, Orkz could take over a planet in a few days, after that there is typically massive in fightiing between clans unless a warboss (  a king of sorts) takes over all of the tribes.
Despite almost constant population culling,  the orkz still managed to pull together a culture. ( A caste based society, based on size, implants, and gun quality)

[mainiac]

IIRC humans have recovered from a genetic bottleneck, however I suspect that the social effects would be more profound in a sentient species.  If a wild dog has twelve puppies and most die, that's just the way things are in the wild.  But humans are conditioned to invest in each children.  But that conditioning would need to be removed, it would be dangerous to the future of the species.  This is all very speculative on my part of course, I just thought it was interesting.

Artificial insemination does offer an escape, but that's a relatively recent development.  We developed nukes first so we could have bottlenecked ourselves before developing the cure.

[alway]

Even with extreme inbreeding, the worst of the traits would only affect some of the population. The inbreeding effects are essentially a bunch of recessive genes associated with negative traits which then are able to be expressed in the population. However, even with inbreeding, they probably won't become the dominant traits; especially if they are disfiguring. Worst case scenario, a previously rare trait exists actively in 25% of the population and inactively in another 50%. It would need some sort of advantage (or lots of luck early on) in order to become uniform throughout the species; a disfiguring condition would at worst make up some minority of the society due to a lack of those willing to mate.

Secondly, long before enough inbreeding to turn the population into space orcs occurred, the population would probably be large and diverse enough for natural mutation to counter the effects associated with inbreeding. If, however, there were several genetic bottlenecks in succession, some of the more extreme traits may start to be seen.

Edit: If it was a nuclear war which resulted in the bottleneck, there would be both enough groups to survive, as well as much higher mutation rates negating the effects of inbreeding.

[mainiac]

That would be true if it was one trait, but what if you are looking at thousands of traits?  If everyone starts expressing dozens of previously rare traits at once, I think the results are gonna be pretty ugly.

[Puzzlemaker]

http://en.wikipedia.org/wiki/Red_wolf#Captive_breeding_.26_reintroduction

http://en.wikipedia.org/wiki/Cheetah#Genetics_and_classification

Two good examples of genetic bottlenecks; both species recovered/are recovering.  Inbreeding isn't the end all that you are making it out to be, but it does do damage to the species.

HOWEVER, if we are talking about space orcs/orks and others like them, I had a couple of interesting theories of my own.  I thought a lot about it.


Humanity evolved into an adaptive species, which is why it covered the entire planet even before civilization rose.  However, what if an intelligent species evolved to survive only in a much smaller region?  If only a small portion of the planet is capable of sustaining the species?  Due to limited room, it could be theorized that the species would be very territorial and expansionist, taking advantage of any square centimeter of land they can grab.

Now lets also say the entire planet is incredibly harsh.  To survive, the species has a lot of children and a lot of child deaths.

Those two factors combined is a grenade primed and ready to explode.  If they get tech that lets them live outside of their region and reduce child mortality, expect a huge population boom and a huge expansion.  It would also give a huge drive to improve their technology even more, to allow the colonists to live more comfortably and to expand further. 

I can easily see this being expanded to space as well, since specialized environmental tech that allows you to live in hostile environments would be extremely advanced.  Seeing them using that tech to live in space isn't that hard, and it would allow them to quickly colonize and expand into space.

And then you would have the perfect setup for space orcs.  Hardwired to expand into every available nook and cranny, reproducing very quickly, and very territorial.

[mainiac]

How limited a space are we talking about?  Polynesian cultures spring to mind as one of the most isolated human examples.

[Vattic]

IIRC humans have recovered from a genetic bottleneck, however I suspect that the social effects would be more profound in a sentient species.  If a wild dog has twelve puppies and most die, that's just the way things are in the wild.  But humans are conditioned to invest in each children.  But that conditioning would need to be removed, it would be dangerous to the future of the species.  This is all very speculative on my part of course, I just thought it was interesting.

Were we not sapient at the time? I was also under the impression that child mortality rates were much higher in the past and one of the reasons for traditionally large families.

[mainiac]

Well, sapient is probably the wrong word.  I'm thinking about the trend of affluent societies to move towards smaller families.  At the same time, it's not just child mortality but adolescent mortality.  Babies are cute, but they can't hold a conversation.  I imagine it would be harder to watch the death of a 14 year old from a disease that you gave them.  Still, I might have overestimated the effects of inbreeding on life expectancy.

[Virex]

http://en.wikipedia.org/wiki/Red_wolf#Captive_breeding_.26_reintroduction

http://en.wikipedia.org/wiki/Cheetah#Genetics_and_classification

Two good examples of genetic bottlenecks; both species recovered/are recovering.  Inbreeding isn't the end all that you are making it out to be, but it does do damage to the species.

HOWEVER, if we are talking about space orcs/orks and others like them, I had a couple of interesting theories of my own.  I thought a lot about it.


Humanity evolved into an adaptive species, which is why it covered the entire planet even before civilization rose.  However, what if an intelligent species evolved to survive only in a much smaller region?  If only a small portion of the planet is capable of sustaining the species?  Due to limited room, it could be theorized that the species would be very territorial and expansionist, taking advantage of any square centimeter of land they can grab.

Now lets also say the entire planet is incredibly harsh.  To survive, the species has a lot of children and a lot of child deaths.

Those two factors combined is a grenade primed and ready to explode.  If they get tech that lets them live outside of their region and reduce child mortality, expect a huge population boom and a huge expansion.  It would also give a huge drive to improve their technology even more, to allow the colonists to live more comfortably and to expand further. 

I can easily see this being expanded to space as well, since specialized environmental tech that allows you to live in hostile environments would be extremely advanced.  Seeing them using that tech to live in space isn't that hard, and it would allow them to quickly colonize and expand into space.

And then you would have the perfect setup for space orcs.  Hardwired to expand into every available nook and cranny, reproducing very quickly, and very territorial.

That doesn't explain the general stupidity and inability to even learn how to speak normal though. At some point everyone of the race has to have contracted some mental defect or they're not Orcs but Klingons...