Let It Out 2017-03-02

[Dave]

I've always found ST approach to genetics terribly flawed. With the technology at their disposal, identifying and fixing genetic problems should be easy, even if they only had 2 people to start with.

It's a bit trickier than that. Genetic problems, per se, are only half of the issue. The other half is genetic diversity.

If you have too small a population, it becomes increasingly likely that some particular genes will be lost, simply by random chance. If (for example) there's only one person carrying a particular allele, and he (or she) has two children, then there's one chance in four that neither of the children will inherit the allele, and it becomes extinct.

This sort of low-population genetic "bottleneck" reduces the genetic diversity of the population, and it doesn't recover (except very slowly, as a result of mutations) after the population increases again. A population can end up being genetically quite uniform - not as much as clones, but not far from it. Even if all of the genes are "healthy" ones (no lethal or harmful alleles at all) the species can end up very vulnerable to disease and environmental change, because they''ll all have the same types of resistance or lack-of-resistance. A lot of our carefully-bred mass-farming plant varieties are vulnerable to this - all it takes is one new mold or bacterium coming along, and it can wipe out an entire crop all across the world because none of the varieties being farmed have any resistance to it.

(There's evidence that the human race has been through that sort of bottleneck. A tribe of chimps or bonobos, all living within 20 miles of one another, have more genetic variation within that small group than the entire human race has in many of its genes.)

To get around this with genetic engineering, you'd have to create a complete "gene bank" of the species, and then either manually "program" the genes of every new generation, or re-introduce endangered or extinct alleles every few generations to counteract random losses. Either approach would be expensive, and prone to totalitarian abuse.

[Dave]

I suspect AFF may recognize it... anybody else?)

Drawing a blank so far...

"The Time Stream", by John Taine (the pen name of mathematician Eric Temple Bell). First published in 1931. It's probably his strangest and most philosophical novel.

It's available at the Canadian site of Project Gutenberg.

[FreeFlier]

. . . This sort of low-population genetic "bottleneck" reduces the genetic diversity of the population, and it doesn't recover (except very slowly, as a result of mutations) after the population increases again. A population can end up being genetically quite uniform - not as much as clones, but not far from it. Even if all of the genes are "healthy" ones (no lethal or harmful alleles at all) the species can end up very vulnerable to disease and environmental change, because they''ll all have the same types of resistance or lack-of-resistance. A lot of our carefully-bred mass-farming plant varieties are vulnerable to this - all it takes is one new mold or bacterium coming along, and it can wipe out an entire crop all across the world because none of the varieties being farmed have any resistance to it.

This is the case with bananas and sugar cane . . . something like 99% of bananas are Dwarf Cavendish, and sugar cane and rubber trees are similarly worldwide monocultures . . . the prior varieties of both all three been wiped out by disease, with resulting production crashes until a different, resistant variety can be found and propagated.

. . . (There's evidence that the human race has been through that sort of bottleneck. A tribe of chimps or bonobos, all living within 20 miles of one another, have more genetic variation within that small group than the entire human race has in many of its genes.) . . .

This may also be due to humans being a fairly new species that evolved from a comparatively small isolated group . . . that is, the genetic diversity wasn't there in the first place.

. . . To get around this with genetic engineering, you'd have to create a complete "gene bank" of the species, and then either manually "program" the genes of every new generation, or re-introduce endangered or extinct alleles every few generations to counteract random losses. Either approach would be expensive, and prone to totalitarian abuse.

Totalitarian abuse is a bad thing . . . but so is dying out though a lack of genetic diversity . . . name your poison.

--FreeFlier

[AnotherFairportfan]

I suspect AFF may recognize it... anybody else?)

Drawing a blank so far...

"The Time Stream", by John Taine (the pen name of mathematician Eric Temple Bell). First published in 1931. It's probably his strangest and most philosophical novel.

It's available at the Canadian site of Project Gutenberg.

I've read some "Taine", many years ago, though not that one, i don't think...

I'll take a look.

[ShirouZhiwu]

Genetic diversity could be artificially introduced if you have enough genetic knowledge. I'm also pretty sure Kahn's people ended up the way they are because they copied the brain dna from world leaders. It made them sociopathic.

[TazManiac]

(There's evidence that the human race has been through that sort of bottleneck. A tribe of chimps or bonobos, all living within 20 miles of one another, have more genetic variation within that small group than the entire human race has in many of its genes.)

It's almost certainly to have happened; Ice Ages, Catastrophes that wiped out all but a handful (floods, fires, 'crop' failure [due to overgrazing or drought, etc], Viral Pandemics... Mother Nature is a harsh filter.

And I was thinking re: Thor's post- often the paras in Wapsi and elsewhere, are very long lived. It would make for more opportunities at genetic dice-rolling to 'keep things fresh' so to speak...

[Typeminer]

Genetic diversity could be artificially introduced if you have enough genetic knowledge. I'm also pretty sure Kahn's people ended up the way they are because they copied the brain dna from world leaders. It made them sociopathic.

Jacked-up steroidal hormone production might have helped with that, too.

[TazManiac]

In addition to greater strength and stamina, mental capacity, they where also said to have cranked up the Aggression portion to past 11 on the dial...