
Genetics and Eugenics in Frank Herbert's DUNE - blopeur
https://www.gwern.net/dune#genetics-and-eugenics-in-frank-herberts-dune
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lnanek2
The author claims 20 generations would be enough to breed the powers shown and
thousands is unrealistic: " even the most pessimistic estimates of how many
generations it might take to drastically increase average human intelligence
or almost entirely eliminate a nasty recessive by R.A. Fisher might be 20
generations . "

But some of the powers, like remembering ancestors memories barely even exist
in humans today. The field of epigenetics has proven that a starving parent
can alter how the genetics of even grandchildren express themselves. So some
basic functions like wrapping DNA tighter or loser and adding a methyl
chemical group exist to pass information across generations, but this is like
an extra bit or two per gene. To extend the functionality to the level of
recording memories would take almost as long as it took for DNA to become as
fancy as it did from the original RNA molecules that could produce more of
themselves without any enzymes or DNA having developed yet. So almost as long
again as life itself has taken, not 20 years.

~~~
gwern
> But some of the powers, like remembering ancestors memories barely even
> exist in humans today.

That would be a valid point... except why are they still breeding for things
like intelligence? That was my point. Thousands of generations later, they're
still breeding for basic stuff like enhanced intelligence, which makes little
sense under pretty much everything we know about intelligence's genetics.

> The field of epigenetics has proven that a starving parent can alter how the
> genetics of even grandchildren express themselves.

The extent to which transgenerational heritable epigenetics matters in humans
has been wildly exaggerated by the media and the field is rife with
overinterpretations, small samples, and non-replication.

Not to mention, even that hype didn't exist when Herbert was writing it, so he
couldn't've been thinking of it. I am fairly sure he was gesturing towards a
more Akashi-Records-style psi mechanism with access granted by ancestry, not
actual encoding of memories into spare DNA (which among other things would
mean no ancestor would remember anything after having a kid).

> To extend the functionality to the level of recording memories would take
> almost as long as it took for DNA to become as fancy as it did from the
> original RNA molecules that could produce more of themselves without any
> enzymes or DNA having developed yet.

Neurons already re-edit and splice their chromosomal DNA, so the mechanisms
are already there for at least part of it.

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badloginagain
I always assumed that the BG were directing genetic averages across whole
populations, and/or had such a deep understanding of genetics that they could
predict the exact result of two peoples genes mixing.

If you could determine with 99% accuracy the exact genome of a child by their
parents genomes alone, would you be able to optimize humans across given a
relatively small set?

~~~
philipov
Except that gene mixing is a highly quantum mechanical process, and so we are
precluded from predicting the result of a single event. We can only predict
the probability of a particular mix of genes. They could direct averages, but
not individual events.

~~~
dbasedweeb
Of course with the spice and mentats, they could probably use some limited
form of prescience to explore possible avenues the future was likely to take.
It is a universe in which magic, by another name, works.

~~~
philipov
Once you accept that premise, throw rationalizations out the window. There's
no point theorycrafting, just make up anything you like. Whether or not
something is possible is a function of what is needed for the story. The
answer to any such question is, "Do you want it to be?"

~~~
simonh
The best science fiction and fantasy begins by taking a few specific
assumptions, which may be fantastical, but then exploring the consequences of
those assumptions in a disciplined way. For example having one form of FTL
travel with known limitations in an SF setting and exploring the possibilities
within those rules.

Writers that take your approach - it’s all made up so I’ll just make up new
rules whenever so feel like it - are rarely satisfying because the reader
can’t trust anything or reason about the setting or the characters choices.

This is the problem with J.J. Abrams approach Star Trek and Star Wars. He
seemed to take a special glee in arbitrarily violating established conventions
in the settings with respect to things like how Warp Drive and Transporter
technology work in Star Trek.

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HelloNurse
Very interesting, but fantastic genetic traits like precognition and ancestral
memories are (in fiction) a traditional good fit for the Mendelian inheritance
pattern of few and high impact mutations.

~~~
gwern
I've idly wondered how you could interpret all the mutations in X-Men, but I
don't know enough about the families or inheritance to make any reasonable
guesses (I've seen a few cartoons and movies and that's about it). I know
mutants generally have mutant kids but don't the powers differ? Which doesn't
make much sense and I can't retcon it.

I have noticed, however, that in _My Little Pony_ (which I've finally gotten
around to watching), it seems like earth/pegasus/unicorn traits are not races
or subspecies analogous to human races but instead likely follow a polytomous
liability threshold pattern. Why? Because we see the Cakes, two earth ponies,
manage to have a pair of pegasus and unicorn fraternal twins, and when
queried, mention they have some pegasus/unicorn ancestry. Since the pony type
is mutually exclusive (we never see any pony who is both pegasus and unicorn,
aside from the alicorns who are special magically-created cases), I don't know
of any kind of common Mendelian trait pattern which would give a single type,
normally breed true, _and_ allow two earth pony parents with mixed ancestry to
have kids who are both unicorns _and_ pegasi (one non-earth-pony offspring
would be fine as it would simply indicate a recessive discrete trait, but two
different others? I don't see how that works unless you postulate some sort of
multi-locus Mendelian trait with dominance of earth trait by both unicorn and
pegasus, I guess?). Whereas if it's polytomous liability threshold, then that
would be possible albeit unlikely, since they could inherit different
fractions of ancestry and get pushed across different type thresholds.

~~~
a_t48
Why not two traits? One that determines if (Earth || !Earth) (call it the
"Magic" gene) and one that determines (Pegasus || Unicorn) but only if the
other gene is active.

~~~
gwern
I don't really like some of the mechanisms like dominance because it implies
something for which we have no canon evidence: biases in discordant offspring
towards particular types. And requires some rather specific patterns: in that
case, it would require Mr and Mrs Cake to both have exactly 1 Earth/!Earth
allele pair (so they become Earth but have a !Earth which can be passed on)
and then each has a different Pegasus or Unicorn allele, which then also
separately get passed on so they have two kids with !Earth/Pegasus and
!Earth/Unicorn pairs. And it seems like if that were how it worked, you would
expect way more discordant families to show up. (While polytomous threshold
model can accommodate any level of rarity or stochasticness quite easily and
naturally.)

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downer56
This is the best write-up of Dune that I’ve ever read. Some of gwern’s stuff
is kind of overcooked to a fault, and with intense focus, misses the broader
prevailing drift of the topic at hand, but gwern’s got me on this one. It’s a
good read.

~~~
gcb0
thought genetics and the BG religion is more a deus exmachine than the main
plot.

the main plot is an alegory of all the wars USA entered so oil prices remained
under control.

the oil must flow.

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madengr
Had to stop reading due to spoilers. Currently on Children of Dune.
Alternating between that series and Asimov.

~~~
pmoriarty
_Children of Dune_ and _Dune Messiah_ are, imo, the weakest of Frank Herbert's
_Dune_ series. Persevere through those and you'll be rewarded in his later
books.

~~~
ry_ry
It probably doesn't bear repeating at this point, but Brian Herbert's dreary
offerings are pretty dismal and should be avoided by all but the most ardent
Dune aficionados jonesing for a spice-fix and/or sci-fi masochists hoping to
negate any enjoyment they derived from the Herbert novels.

Full disclosure: I didn't enjoy the Brian Herbert stuff.

