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Say we want to breed an animal with certain traits. We
have to wait till the animal is old enough to become a
parent.
This idea is to take the DNA from an animal not that far
beyond the zygote stage and use it as the next level
animal
by inserting those DNA into the next sperm/ovum.
No
I am totally ignorant of this process, I heard that
they're creating mother/fatherless fertilized cells in the
lab but I could be totally wrong about this. In my
ignorance
I might have just suggested the bioligical equivalent of
hooking a generator up to a motor for a perpetual
motion
machine.
However, if it's possible to skip the maturing process of
"parent" cells, well... this could be a thing.
Preimplantation Genetic Diagnosis
https://en.wikipedi...n_genetic_diagnosis
[Cuit_au_Four, Oct 21 2017]
wikipedia Strange attractor
https://en.wikipedi...r#Strange_attractor
[beanangel, Oct 21 2017]
Quantum biology
https://en.wikipedi...iki/Quantum_biology
An expanding field of study [8th of 7, Oct 22 2017]
It's Crispr Bacon!
https://techcrunch....duce-low-fat-bacon/
[theircompetitor, Oct 24 2017]
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Could this be applied to breeds of dogs other than
Labradors? |
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You could, sort of maybe almost, do this. You're basically cloning consecutively from embryos. Plant tissue culture does this a lot, but simply for the purpose of multiplying a plant very fast. |
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Howevertheless, there's no point, at least for what you want. Not only that, but there's no point for two independent reasons. |
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(a) If you're trying to selectively breed a new trait, then you are relying on (i) random shuffling of pre-existing variants in the course of sexual reproduction and (ii) rare random mutations in the germline cells that produce new variants. In the case of things like dog breeding, it's mainly (i). Your iterative cloning process won't accomplish (i) because there's no shuffling; and it won't achieve (ii) very effectively, because you haven't got cells sitting around accumulating new mutations for very long. |
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(b) In most cases, you want to breed for traits that are only manifest in the adult (or at least part-grown) animal. You can't select embryos on the basis of intelligence, hair colour, or whatever. |
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It's not such a dumb idea, but it won't work very well. |
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//It's not such a dumb idea, but it won't work
very well.// |
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I don't think I've ever had a post so appropriate for
those humorous halfbakery subtitle tag-lines so,
[marked-for-tagline] |
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//In most cases, you want to breed for traits that
are
only manifest in the adult (or at least part-grown)
animal.// |
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That's where your team comes in. You figure out
some way to extrapolate or interpolate or
extractify
those traits using science. Perhaps get a bunch of
biologists with lab coats and stern expressions on
the
job. Throw a couple of clipboards in. Thick black
rimmed glasses might be good. Furrowed brows,
microscopes, beakers. You know, science. |
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//Could this be applied to breeds of dogs other
than Labradors?// |
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Time it took me to get that: Third reading. |
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// using science// Whoa there. You forgot the capital "S". Anyway, it won't even be worth trying unless we can have some blue liquids in spindly glass tubes. Also we'd like a slightly hunch-backed lab assistant with a speech impediment. |
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Well, you're just a smidgen overqualified to be a lab assistant, but otherwise perfect for the role ... if you can straighten up a bit. |
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There needs to be a big computer, too, with reel-to-reel tape tape drives and rows and rows of flashing lights .... |
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Gotta be some practal use for a Jacob's ladder in
there. Making sure nobody's trying to listen to the
radio in the lab or something. |
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And of course some of those big old quadrant moving-coil meters in black bakelite cases, and a few we-belong-dead knife switches .... |
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Speaking of Labradors, [max] could your science thingy
confirm if dogs on the Korean Peninsula, particularly the
northern part, are evolving faster given both higher
radiation levels and ongoing efforts to avoid being eaten? |
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Tr. "Yes, we could, but only you're prepared to fund an extensive
and expensive progamme of research carried out at our new
corporate HQ in the Cayman Islands". |
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Note that "could" is the future conditional tense. Thus, "could
your science thingy confirm" is definitely NOT the same as "does
your science thingy confirm" ... |
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Somehow, our spellchecker has learned the word "Nebelwerfer".
This is quite bizarre. The circumstances and context in which
autocomplete suggests it are even more bizarre. |
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In my experience, if you want something fast, don't
start with a Labrador. Maybe a greyhound. Or skip
that for a private jet option. Too many weird people
ride on greyhounds. |
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//blue liquids in spindly glass tubes// |
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With bits of dry ice in them. It's not real science if it doesn't have dry
ice in it. |
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"Morning lads. You boys had any luck creating super
fast evolving life?" |
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"Mmmm, sorry boss, not yet." |
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"Hmm. Jacob's ladder looks like it's working ok. Got
enough dry ice in the test tubes?" |
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"Just filled 'em up, and Mongo's been over there
hitting the main knife switch every hour or so
while laughing maniacally. Still no luck." |
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"Ok lads, well, keep it up. Science takes time. No
rush as long as the research grant money keeps
coming. Carry on." |
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Well, if anyone's spell-checker was going to learn "Nebelwerfer", it
was going to be [8th]'s. |
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Whatever you're breeding needs to grow up so you can select for your
desired trait. Otherwise it's not evolution, it's just a new and worse
way to do rational design. |
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// Whatever you're breeding needs to grow up // |
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Give up breeding democrats then. They never get beyond the "whiny little kid" stage. |
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//Whatever you're breeding needs to grow up so you can select for your desired trait.// If only someone had mentioned that in the second annotation. |
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When can we start identifying traits in a zygote?
The traits of the organism are all programmed in
at the moment of conception. |
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I'm assuming we can tell the difference between
fertilized lizard ovum and a that of a giraffe no? |
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Can we just adjust that microscope a bit more
carefully and go "Oh look, this giraffe will like
country music."? |
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But seriously, the traits are locked in, the building
blocks are there. Until this idea there's never been
a reason to look for them at these early stages.
Maybe we can't see these traits because we've
never looked for them before. |
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//When can we start identifying traits in a zygote? // |
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Tricky. In theory, you should be able to simulate development from the genome sequence (plus a few external parameters). Or at least you could if you could sequence the genome without destroying the zygote. |
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In practice - not a hope in hell. You can tell simple things, like whether it has the gene for a particular enzyme. And you can say "this one has the same as this other one". |
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What we are not even remotely vaguely close to approaching the faintest chance of maybe being able to do at all is to take the genome and say "ah yes, it'll have unusually long ears", or whatever. |
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The genome is not a blueprint. It's a fantastically complex recipe, whose outcome depends on the interplay of a thousand factors, each of which depend on another thousand factors. |
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And, in any case, if we could look at a genome and say "Oh yes, this one will be artistic", then there'd be no point doing the evolution stuff. Just make a genome that does what you want and stick it in a cell. |
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Optimistic as I am, I think it will be at least 50 years before we can predict, a priori (and without comparing to known examples) how a genome will turn into an organism. We know a huge amount about development, and what we know is an infinitesimal fraction of what we need to know. |
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// When can we start identifying traits in a zygote? The traits of the
organism are all programmed in at the moment of conception. |
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Well, in a sense, we can already do this sort of evolution, but only
to
remove an unwanted allele. (e.g., a disease
allele). It's called preimplantation genetic screening, and it is
performed
for couples who know that they are both carriers of a disease.
Biopsies
that test for the presence of the undesired allele can be performed
on
embryos obtained from eggs that have been fertilized in vitro.
Depending on the result of the biopsy, the embryo is either
implanted
into the womb or discarded. This is most useful for preventing rare
heritable maladies for which there is no cure such as lysosomal
storage
diseases. |
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I say that this is evolution "in a sense" because it is genetic
modification
that is inherited in the offspring. If you keep doing this for long
enough,
you can "evolve" the population so that it no longer harbors the
undesirable
allele. But this sort of evolution is different from evolution by natural
selection because the latter sort requires the selection of the gene
product by the environment as well as random mutations to
generate new alleles. |
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I
think
that within the next two decades, we will be able to greatly reduce
the
incidence of large numbers of genetic diseases with this technique.
The
thousand-dollar genome has arrived, so all we need now is to
routinize
genetic screening. |
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I guess my next question would be, if we take two
eggs, one we know will produce large ears one
with small ears how far back in its developement
CAN we go seeing a difference? |
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When they're born you just look at them. One has
big ears, one small. Two thirds into the gestation
same thing, you just look, but when you go further
back, day by day, when does the indicator of
difference disappear? That blueprint for those ears
is in there someplace, I know it is. |
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Going backwards, once the visual indicator is of no
use, where is that big ear gene hiding? Does it look
identical to the small ear gene? |
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I'm probably getting into stuff that gets tought in
community college Bio 1.01. |
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This is why if I didn't have to work for a living I'd
spend the rest of my days getting my degrees in
physics, biology, medicine, aerospace, and
engineering. The more I learn the more I realize
how ignorant, or maybe I should say, uninformed I
am. And the fun part of opening all these doors of
knowledge is that they lead to the next, and the
next till eventually you get to the one
titled "We just don't know" with it the unwritten
challenge: "Might you be the man who opens this
door?". |
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Another approach is to make eggs and sperm from stem
cells derived from skin. Mix the sperm and eggs to make a
blastocyct or zygote. do this at a 1000 x 1000 matrix (one
million blastocysts. Then sample 1 cell from the
blastocyst or zygote and gene sequence it.
Thus out of a million possible offspring you could find the
one with the highest expression of a gene of interest,
although you have to know in advance what gene you
want expressed like blue eyes or tallness or puffy pale
nipples |
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Then, turn the zygote into stem cells again, rather than
growing the human, then repeat the process after mixing
it with a different human. You could recombine human
parents say once a month, or 11 generations in 11
months. This way you concentrate any preferred genetics
as long as you know what the genes do in advance. It is
accelerated design rather than accelerated evolution. |
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Setting aside for a second the "puffy pale nipples"
line, Max? Does any of this make any sense? |
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//we will be able to greatly reduce the incidence of large numbers of genetic diseases with this technique// It's likelier that genome editing (initially of zygotes; but later with adults, including their germlines) will take over from this method sooner or later. |
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//Another approach is to make eggs and sperm from stem cells derived from skin.// Well, yes and no. As a way of sampling the genetic diversity available from two people, it sort of works. However, you still have the problem that the only things we can really screen for (pre-development) are abnormalities. |
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OK, think of dog breeding. You want a dog which has a compact muscular body and a good sense of smell. Very simple requirements. We know about genes for achondroplasia (dwarfism - Bassetts and Daschunds) and maybe anosmia (major smell deficit). But we have not got the first flying fuck of an idea of any of the genetic factors that determine stockiness, or nose shape, or density of olfactory receptors. |
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It's the same in humans. We can identify and screen for (or, soon, fix) genetic defects that produce clear deficits (like cystic fibrosis or Duchenne muscular dystrophy). But we haven't a clue which genes give a strong jawline or almond eyes. |
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Every so often, the press will say that "researchers have found the gene for musical ability" or whatever. It is almost invariably complete bollocks. At best, they mean that some gene variant has been found more often in musicians than in, say, drummers. It's like saying that a Porsche badge makes cars go faster. |
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Our current understanding of genetics is still very much at the stage of saying "if you break this gene, this bit stops working". |
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We shelved the radioactive spider project after it produced David Icke. |
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Indeed they are. And they are probably the best-studied and best-understood morphogenic genes. |
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But ask why they produce 7 segments in the abdomen a Drosophila, but 8 in the abdomen of a Rhodesian grape-gnat; or why humans aren't segmented in the same way as wasps; or why our thighbones are longer than our thumbs, and we haven't really got a clue. These are very basic questions that we don't have any inkling of how to answer. |
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Morphogenesis is really, really, REALLY difficult. What's even more remarkable is that, despite its being such an incredibly complex process that involves both quantitative and qualitative interacting patterns of gene expression, it usually works. It's like a recurring storm that always looks chaotic and butterfly-wing-effecty, but always always causes a hailstone to hit the same spot. |
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I suspect that there is some sort of new mathematics at work, which we will need to understand before we get much further. I am tempted to use the phrase "stably convergent fractality", but I don't want to sound like [JHC]. |
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wikipedia link to "strange attractor" as a sidecar to "stably
convergent fractality" |
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//it is performed for couples who know that they are both carriers
of a disease.// |
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Excuse my ignorance of the basics, [Cuit au Four], but this
confuses me. If both parents know they carry the pathogenic
allele, and if a zygote comes from them and not from a donor on
either side, then how is that zygote *not* going to have the
pathogenic allele? I mean, does one just hope for a favourable
random mutation, presumably against rather long odds? |
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It depends if the fault is dominant or recessive. |
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Mostly, the faults are recessive, so there's about a 25% chance of an affected zygote and a 50% chance that the zygote will be an asymptomatic carrier. |
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If the fault is dominant, then there's a 75% chance of an affected zygote and the gene line doesn't endure. |
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// It's mad Ted isn't it ? // |
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Or quantum effects manifested at a macroscopic level. <link> |
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Ah. Right. Yes. Thank you. Google tells me there can be more
than one allele of the same gene in a given somatic cell, and I
infer that not all the (single-allele) germ-line cells from a given
parent get the same allele. That makes sense now, so I hope it's
true. |
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The only time you'd really be stymied in the way I'd imagined
would be when both alleles in both parents (so, four out of a
possible four alleles) were duds. I imagine it wouldn't happen for
the worst mutations, because then neither parent would live long
enough to parent. |
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Males wouldn't. Females have a 50-50 chance. |
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Females have two X gender chromosomes, but in any given cell either can be active. So if one X chromosome is faulty, enough cells may have a functioning copy to suppress the effect. |
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But if the offspring gets the faulty copy, then it'll be affected. |
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Don't quote us but that may be how hemophilia works - females are only carriers, males with the faulty X chromosome are affected. |
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An interesting study is the Ptolemies of Egypt who married incestuously. Over 13 generations, the males progressively degenerated, becoming obese, of low intelligence, and prone to numerous complaints, whereas the females remained relatively normal. The XX duplication confers some protection against inherited conditions. |
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Any relationship between this phenomenon and the
fall of the pharoaic dynasties? (don't know if
pharoaic
is a word, should be) |
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(re post) Quantum biology is a thing? Wow. See
what I
mean about the more you know the less you know? |
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I don't know if knowledge is infinite, which is kind
of ironic, but I assume when you truely unlock all
the secrets of the universe something happens.
Maybe you turn into God. Wonder if you'd get
bored and press the reset button and start all over
again. (The reset button erasing all knowledge that
you'd of course be able to easily design.) |
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I think "pharaonic" is the word you're looking for, [dr]. |
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// relationship between this phenomenon and the fall of the pharoaic dynasties? // |
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It was a significant factor. But you have to look at the larger geopolitical context. |
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The Ptolemies were descendants of one of Alexander the Great's generals. They were Greek, not Egyptian, but they rapidly "went native". |
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In the 1st Century BC, Rome was aggressive and expansionist. Egypt was critically important as a grain supplier to Rome. The ptolemaic pharaohs were just puppets for their sister/wives, who constantly squabbled. Then there was the whole Julius Caesar/Cleopatra/Mark Anthony thing and then after the civil war Rome (i.e. Octavian/Augustus) decided to take over Egypt as a wholly-owned subsidiary. |
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// Quantum biology is a thing ? // |
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Yes. Please, do try to keep up. |
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// I don't know if knowledge is infinite, // |
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// I assume when you truely unlock all the secrets of the universe something happens. // |
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Yes. We instantly became insufferably smug. |
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// Maybe you turn into God. // |
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// Wonder if you'd get bored and press the reset button and start all over again. (The reset button erasing all knowledge that you'd of course be able to easily design.) // |
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Not yet, we want to see how it turns out. |
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//// Quantum biology is a thing ? //// |
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It sort of is. I mean apart from the fact that everything is quantummy if you go deep enough. |
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It's difficult to prove, but it is believed by some that certain biological process have evolved to utilize quantum-level effects. One candidate is magnetoception in birds, where the incredibly weak field is believed to bias the outcome a quantum event in order to produce a signal. Another is the sense of smell, which may involve quantum-level coupling between odorant and receptors. Yet another is photosynthesis (so, a biggie), where quantumness may be exploited to achieve the observed high efficiencies of electron transport. |
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If photosynthesis has touching strokes of quantumness, wouldn't the mitochondria's electron transport chain also have accessed other direction's extras? |
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Possible, but not certain. |
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//Males wouldn't. Females have a 50-50 chance.// |
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{I wade deeper into the bio-diverse wetland of my own ignorance,
whose further side is still obscured by fog} |
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... But ... I was postulating a scenario in which each parent had
two bad alleles (of the same gene) in each somatic cell. In that
scenario, how does the second X of the mother help? Does it
increase the number of possible alleles (of the same gene) in the
somatic cell to more than two? |
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Also ... {nervously exposes further ignorance} ... aren't the X and
Y variations relevant for only a small minority of genes anyway,
given that most chromosomes are autosomes? |
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Humans have two each of chromosomes 1-23; and either 2 X chromosomes (females) or X+Y (male). |
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Most mutations are recessive, meaning that you're OK as long as you have at least one good copy of the gene. So, if the gene is on an autosome (for instance, Chr1), you might have two parents who are carriers: they each have one bad and one good copy of the gene. The child then has a 50:50 chance of inheriting a "bad" copy from each parent, and therefore a 1 in 4 chance of getting bad copies from both parents and being sick. There's also a 1 in 4 chance of the child getting a "good" copy from each parent, in which case the child is fine. There's a 1 in 2 chance that the child will inherit a bad copy from one parent and a good copy from the other, in which case the child will be fine but will be a carrier like his/her parents. |
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If the gene is on the X chromosome (and if it's also a recessive mutation), then it's likely that the father is normal (ie, his only X chromosome has a good copy of the gene) and the mother is a carrier (one good copy, one bad copy). So, a daughter will either have one good copy (from her mother) and another good copy from her father; or a bad copy from her mother and a good copy from her father. In the latter case, she'll be an unaffected carrier like her mother. A son, however, will either have one good copy from his mother (and will be fine), or will have one bad copy from his mother (and will be affected, because there's no second copy to compensate). |
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If the father is affected (has a bad X) and the mother is a carrier, then all girls will be either carriers or will be affected. If the father is affected and the mother is fine, then all girls will be carriers and all boys will be fine. If the mother is affected (she has 2x bad X's) and the father is affected, then all children will be affected. Etc etc - you can work out the other options. |
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Some mutations are dominant (ie, one bad copy is enough to screw you, even if you have another good copy), and you can figure out what happens there. |
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Er, we thought we explained that already ... ? Well, not in such Managing Director simplicity, but the essentials were there, if the reader has but the barest minimum of intelligence... |
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What causes a change to a bloodline of an
organism that gets tested by the environment such
that good changes live to reproduce and bad
changes don't? |
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Is it radioactivity? Is it just random chemical based
screwups at the cellular level? |
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An animal that has winglike appendages that it
uses to glide has a kid that learns to flap its wings
because it has better wing muscles. (Obviously it's
a continuum, the parent doesn't just randomly give
birth to this perfectly aerodynamically designed
flying machine.) What caused that? Nuclear
mutation or chemical something or other? |
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What I'm getting at is you can certainly apply
whatever this force is to the freshly fertilized
ovum and speed up a RANDOM evolutionary
process. It wouldn't be tested by nature and you'd
probably end up creating some randomly equipped
freak with 6 heads and wheels, but... well, as long
as we were nice to the creatures we created there
could be value in looking at these things. |
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It's frankly imperfect copying, from what I understand. DNA
has to 'unzip' in order to copy itself. Imagine a bad zipper that
occasionally skips a tooth or adds one in the process of getting
zipped back up to its new zipper side mate. That's one
mechanism, at least something like that. |
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//What causes a change to a bloodline // |
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Pretty much what [Rayfo] said. Mutations can happen in the course of DNA replication, but they also happen through random damage coupled with imperfect repair. Remember, an oocyte will be sitting around for 20-40 years before it gets used. |
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However, when it comes to relatively fast evolution, like creating a new breed of dogs, most of it comes down to shuffling the deck of existing variants more than finding totally new ones. |
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// an oocyte will be sitting around for 20-40 years before it gets used. // |
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That's just appalling. Is there no stock control, no just-in-time ordering ? Who pays for the storage ? Really, it's not good enough. Someone should do something. |
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Well, obviously the male side of the business is much better organised and stock turnover is much higher. On the other hand there's more wastage. |
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Best leave your siblings out of this. |
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Thank you, [MaxwellBuchanan]. I feel that I have now reached a
comfortable spot in the middle of the swamp, from which I can
dial down the mosquito noise and turn on the jacuzzi jets. The
bole of a nearby mangrove conceals an ice bucket, and the
leaches are really quite friendly, once you get to know them. |
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Sp. "leeches", n plur., nauseating repusive bloodsucking parasite, Pr. "lawyers". |
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//photosynthesis has touching strokes of quantumness,
wouldn't the mitochondria's electron transport chain also
have accessed other direction's extras?// |
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Since mitochondria spend quite a lot of time pumping H+
ions, and not a small amount of time letting them back in
again, I like to refer to the proton pool as the "nuclear
working fluid" or maybe complex III becomes "antimycin
sensitive particle accelerator". This achieves little, apart
from making me feel clever and important, I suspect
these feelings are central to the academic pay package. |
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Hmm. I wonder if one could in-vitro evolve an enzyme that catalysed proton-proton or proton-deuteron fusion. Of course, it might only survive one turnover, but that just means we don't need to worry about Kcat. |
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I suspect, although this does mean trusting
chemists which is a worry, that H+ doesn't exist. At
least in a meaningful way. There's nowhere near
enough literature on it, but for the most part biology
deals with H3O+, although thinking about it, I've
clearly been duped by a chemist... H+ diffuses twice
as quick as OH- despite apparently being in the
bigger H3O+/H5O2- species. I knew they were
making it up as they were going along. |
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