Future Space War

In article ,
(Henry Spencer) writes:
| In article ,
| Nick Maclaren wrote:
| | Not in the long run -- not enough genetic variety (mitochondrial DNA in
| | particular comes only from the mother)...
|
| Yes, with the probable exception of your remark about mitochondrial
| DNA. Were it inherited solely from the mother...
|
| It is. Mitochondria have their own genetic material -- ...

See the other postings. It isn't quite as simple as that, but that
is a very good first approximation.

| then all that is
| needed is one woman with sound mitochondrial DNA ...
|
| Note that I said "variety". You assume that there is one optimal (or just
| permanently adequate) choice of the genes involved, but that's a huge
| assumption and quite unjustified. You want *diversity* in this, as in
| other genetic material, to cover against the possibility that different
| combinations will be needed for different future challenges.

No, I am not. If you work out the statistics for sexual and asexual
reproduction, you can see why we have very little mitochondrial
variation. Variety within our mitochondrial DNA isn't a major
factor in our survival. I don't know the exact figures involved,
but there is effectively no mitochondrial variation in quite a lot
of human populations.


Regards,
Nick Maclaren.

In article ,
dave schneider wrote:
[...]
massively overrated as weapons. I'm sorry to shatter illusions, but
Heinlein blew this one badly. Their power supplies have to be too big and
the waste heat would be too hard to hide.


He wasn't positing a secret catapult designed to be used as a
weapon...

Read it again - the book specifically noted that they built (and
later used) a backup catapult, with its own fusion plant, concealed to
avoid bombing by the UN forces. And that the secret weapon remained a
secret long after the war ended.
Jon
__@/

In sci.space.tech Juergen Nieveler wrote:
(Henry Spencer) wrote:

It is. Mitochondria have their own genetic material -- they are
almost certainly the distant descendants of symbiotic bacteria -- and
there are none in a sperm cell. Check any textbook on the subject if
you don't believe me. (In fact, there's active research in tracing
back the details of mankind's origins using genetic comparisons of
mitochondrial DNA, which is hugely easier because that DNA doesn't get
*mixed* every generation.)

Indeed. Of course, the Y-chromosome is used to track the male line :-)

I've once read somewhere about a study performed in Israel on the
family tree of the Cohen-family, which proofed that this indeed could
be traced back to one or very few males X thousand years ago. However,
they also found out that the same Y chromosome was present in males
from other family trees - looks like some men weren't exactly faithfull
over the milennia and did have some illegitimate offspring ;-)


Umm.. Over X thousand years, they are descendedn from people who practiced
temple prostitution - and adoption of resulting babies - a lot. So the
comparison would only be done by peopel who new biologoy but not history...

--
Sander

+++ Out of cheese error +++

"Henry Spencer" wrote in message
...
In article ,
Nick Maclaren wrote:
...
Note that I said "variety". You assume that there is one optimal (or just
permanently adequate) choice of the genes involved, but that's a huge
assumption and quite unjustified. You want *diversity* in this, as in
other genetic material, to cover against the possibility that different
combinations will be needed for different future challenges.

If you selected humans from many different races (and heavily from
Africa) and were ruthless about removing exposed genetic defects,
then a few dozen would be enough for the genetic aspect, ignoring
the freezer. Even less has been for many other mammals, after all...

Kind of, sort of, loosely speaking. Many of the species that have gone
through major population crunches show serious signs of inbreeding, and
are very vulnerable to things like new diseases because of lack of genetic
variety. Variety is key, and even major genetic defects aren't
necessarily
known and obvious.

It should be remembered that in virtually all such cases where species have
gone through crunches that the survivors were all near-kin, and that
subsequent breeding occurred without the explicit goal of preserving such
diversity as had survived.

Fewer than 100 individuals, *properly selected*, can preserve that vast
majority of diversity in a population. And with the help of genotyping, and
the fact that mating and reproduction can be entirely separated today, the
diversity can be preserved in a small population indefinitely. Rare traits
can be preserved using frozen ova and sperm.

The more important constraint is the number of individuals required to run
an industrial econcomy sufficient to make space habitation self-sustaining.
The number number of people employed by industrial corporations and devoted
to large manned spaceflight/aerospace programs number something like
100,000. And then there are all the suppliers of raw materials, components,
and services that support the program and the employees and their families -
but are not devoted to the programs full time.

Even assuming a very human-power efficient economy and society, I find it
hard to imagine a self-sustaining economy for this purpose with a total
population of fewer than 100,000 - barring the availability of technologies
like self-configuring nanotech assembler factories.

Also just cause you are XX or XY, does not mean you are female or male.
It is a small part of what is normally on the Y that says "Male" versus
other.
Also you can have I remember XXY and XYY and such and other forms..
XYY is often supposedly found in psycho killers?

Mike


Juergen Nieveler wrote:

(Henry Spencer) wrote:

It is. Mitochondria have their own genetic material -- they are
almost certainly the distant descendants of symbiotic bacteria -- and
there are none in a sperm cell. Check any textbook on the subject if
you don't believe me. (In fact, there's active research in tracing
back the details of mankind's origins using genetic comparisons of
mitochondrial DNA, which is hugely easier because that DNA doesn't get
*mixed* every generation.)

Indeed. Of course, the Y-chromosome is used to track the male line :-)

I've once read somewhere about a study performed in Israel on the
family tree of the Cohen-family, which proofed that this indeed could
be traced back to one or very few males X thousand years ago. However,
they also found out that the same Y chromosome was present in males
from other family trees - looks like some men weren't exactly faithfull
over the milennia and did have some illegitimate offspring ;-)

--
Juergen Nieveler / / PGP supported!
Aural sex produces eargasms

(Henry Spencer) wrote in message ...
In article ,
Master and Owner, Beryl J. Turner III wrote:
[snip-o-tronic]
You put a mass-driver on the moon, calculate the ballistics and wham!

[....]
I'm sorry to shatter illusions, but
Heinlein blew this one badly. Their power supplies have to be too big and
the waste heat would be too hard to hide.

You get missiles in orbit, wait for the right moment, launch and bam!

The "bam" is the sound of your missiles being hit by ground-launched
antisatellite weapons. Orbit is a *lousy* place to put missiles, unless
you can armor them very heavily. They're too easy to spot and too hard
to protect. Silos dug into hard rock are a far superior location.

Close, but not quite, you had the setup for this one but
missed the follow through. The "bam" is the sound of
your lunar catapult power supplies receiving an "entropy
upgrade" courtesy of your enemies on Earth.

In sci.space.tech Henry Spencer wrote:
In article ,
Ian Stirling wrote:
Not enough to form a viable population, let alone a civilization.

Biologically viable population is one woman and a freezer full of sperm.

Not in the long run -- not enough genetic variety (mitochondrial DNA in
particular comes only from the mother). Also not enough kids in the first

Oh dear.

generation for a stable and capable society, quite aside from practical
problems of taking care of them and educating them.

I was addressing solely biological issues (and screwed that up a little).
Add a freezer full of stored embryos.

A few hundred is probably minimal. A few thousand would be safer.

I think a dozen is probably a bare minimum if you'r going to most places
on an unpopulated earth-like planet. (neglecting biological diversity)
As far as I'm aware there isn't one nearby...

If you are talking about surviving on a barren planet, even with
massive supplies, you'r going to need a lot of people to do it.

Compare medieval villages.
To keep things going, you need hunters, skinners, butchers, leathermakers,
fletchers, coopers, blacksmiths, builders, lumberjacks, sawmill operators,
carpenters, farmers, mill operators, ......
Now add to this things that diddn't need done, such as air purification,
oxygen generation, trace element recycling, leak control, pressure
suit manufacture, ........

I can easily see tens or hundreds of thousands being required for
a stable community that's not simply living off existing stocks.

On 31 Mar 2004 15:37:13 GMT, (Nick Maclaren) carved
upon a tablet of ether:

No, I am not. If you work out the statistics for sexual and asexual
reproduction, you can see why we have very little mitochondrial
variation. Variety within our mitochondrial DNA isn't a major
factor in our survival. I don't know the exact figures involved,
but there is effectively no mitochondrial variation in quite a lot
of human populations.

I'd imagine that's because there's pretty much only one best way to
produce ATP. Mitochondrial DNA doesn't have a lot to do with
immunities, etc., so the only time variation would be of much benefit
would be if something started blocking the action of some vital
protein in the chain, and not a variation of that protein.

--
Rupert Boleyn
"Just because the truth will set you free doesn't mean the truth itself
should be free."

"Henry Spencer" wrote in message
...
In article ,
Nick Maclaren wrote:
...
Note that I said "variety". You assume that there is one optimal (or just
permanently adequate) choice of the genes involved, but that's a huge
assumption and quite unjustified. You want *diversity* in this, as in
other genetic material, to cover against the possibility that different
combinations will be needed for different future challenges.

If you selected humans from many different races (and heavily from
Africa) and were ruthless about removing exposed genetic defects,
then a few dozen would be enough for the genetic aspect, ignoring
the freezer. Even less has been for many other mammals, after all...

Kind of, sort of, loosely speaking. Many of the species that have gone
through major population crunches show serious signs of inbreeding, and
are very vulnerable to things like new diseases because of lack of genetic
variety. Variety is key, and even major genetic defects aren't
necessarily
known and obvious.

It should be remembered that in virtually all such cases where species have
gone through crunches that the survivors were all near-kin, and that
subsequent breeding occurred without the explicit goal of preserving such
diversity as had survived.

Fewer than 100 individuals, *properly selected*, can preserve that vast
majority of diversity in a population. And with the help of genotyping, and
the fact that mating and reproduction can be entirely separated today, the
diversity can be preserved in a small population indefinitely. Rare traits
can be preserved using frozen ova and sperm.

The more important constraint is the number of individuals required to run
an industrial econcomy sufficient to make space habitation self-sustaining.
The number number of people employed by industrial corporations and devoted
to large manned spaceflight/aerospace programs number something like
100,000. And then there are all the suppliers of raw materials, components,
and services that support the program and the employees and their families -
but are not devoted to the programs full time.

Even assuming a very human-power efficient economy and society, I find it
hard to imagine a self-sustaining economy for this purpose with a total
population of fewer than 100,000 - barring the availability of technologies
like self-configuring nanotech assembler factories.

"Dirk Bruere at Neopax" wrote in message ...
"Andrew Swallow" wrote in message
...
"Master and Owner, Beryl J. Turner III" wrote in
message om...
[snip]
Remember, the Imperials in Star Wars were British, not American....

There is a good reason why Hollywood casts British actors as the
villain. To successful pay a bad guy you have to be able to ACT.
Since in real life any one that evil would be in jail. Also the actor

On the contrary.
Quite a few who are that evil are very influential people in the real world.

But generally speaking they are not actors.
And the general point is that british drama training is primarily classical,
teaching the actors how to convey an emotional state through stance, tone,
facial expression and so forth without any requirement to actually feel
that emotion. Which means that villain roles goes to british trained actors
a lot. Most metod actors simply can't really feel the emotional state
of a sadistic *******, or a sociopath. And if they can put themselves in
that emotional state or a good fascimile thereoff, then they are likely to
become really hard to work with. For fairly obvious reasons.
Hence a never-ending row of british actors as villains.