[HN Gopher] Scientists Clone Two Black-Footed Ferrets from Froze...
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Scientists Clone Two Black-Footed Ferrets from Frozen Tissues
Author : Brajeshwar
Score : 80 points
Date : 2024-11-18 15:33 UTC (5 days ago)
(HTM) web link (www.smithsonianmag.com)
(TXT) w3m dump (www.smithsonianmag.com)
| MrMcCall wrote:
| I'm curious how many defects creep into the process. I doubt the
| scientists have any idea, and I'm pretty sure the process
| involves a great deal of statistical inference to reconstruct the
| genome from many, many small chunks of DNA.
|
| How would they even measure their accuracy? By definition,
| there's not even a baseline to measure against, right?
| Etheryte wrote:
| Finding out how accurate this approach is should be trivial,
| no? Take some other baseline tissue where you know the ground
| truth, freeze it, then follow the procedure and check what you
| get. Do this a few times and you'll have a pretty good estimate
| of the accuracy.
| dbetteridge wrote:
| It's an interesting question but prompts the rebuttal, isn't
| that just how things work in nature?
|
| No process is 100% clean in biology, that's how we get random
| mutation and evolution of species
| gus_massa wrote:
| > _How would they even measure their accuracy?_
|
| My guessis that they already used the same tools with sheeps or
| rats in a freezer. Combining that info with some other tool to
| measure how much dqmage the sample gpt [1] may give an
| estimation.
|
| [1] I guess the exact damage depends on how fast it froze and
| the changes of tenperature and other difficut to know details.
| bglazer wrote:
| This process is called genome alignment. It's actually quite a
| fascinating computer science problem that has received a ton of
| study over the years. I think the classical techniques treat it
| as a dynamic programming problem but I'm not sure how the most
| modern alignment tools work.
|
| There are a number of ways that we can check for errors. First,
| there are many different sequencing and alignment tools, each
| with different characteristics. For example, by cross checking
| long read sequencing from a nanopore sequencing deveice and
| more common Illumina paired end sequencing, we can see where
| they agree or disagree and then further check with another
| validated method like Sanger sequencing, if we're really
| confused about which is correct. Also, we already know a bit
| about biology, so we can check the sequence for obviously wrong
| patterns. Like if our sequencing says the ferret has a mutation
| that would destroy a critical protein's function (e.g. a
| frameshift or premature stop codon) but the ferret looks fine,
| then we can reasonably infer that the sequencing was wrong
| somehow. Finally, you're right that there's not a "baseline".
| All processes in biology are inherently lossy. That said genome
| sequencing uses pieces of the cellular machinery (DNA
| polymerase) that can copy gene sequences with incredibly high
| fidelity, so we rely on biology's incredible achievement to be
| reasonably sure that we're getting the "right" answers.
| Mistletoe wrote:
| I'm ignorant about cloning progress made since Dolly. Have they
| made advances on the problem where the clones have accelerated
| aging because they are made from cells that are aged?
|
| >On 14 February 2003, Dolly was euthanised because she had a
| progressive lung disease and severe arthritis.[6] A Finn Dorset
| such as Dolly has a life expectancy of around 11 to 12 years, but
| Dolly lived 6.5 years.
|
| https://en.wikipedia.org/wiki/Dolly_(sheep)
|
| Or was it even a problem at all? It seems clones made later
| haven't had that issue? It shows the power of a meme in
| installing that idea in the consciousness of society.
|
| Google is telling me this in its AI answer.
|
| >Research suggests that telomeres are rejuvenated during nuclear
| reprogramming by somatic cell nuclear transfer (SCNT).
| inciampati wrote:
| Telomere length is dynamically regulated. It sounds like SCNT
| does well at triggering the correct reprogramming to reset
| epigenetic features that might have led to Dolly's troubles
| (although it seems these were greatly overstated:
| https://blog.cirm.ca.gov/2016/07/27/cloning-breakthrough-
| dol...)
| Keysh wrote:
| From the linked _Washington Post_ story: "The cloned animals
| were made by injecting one of Willa's cells into an egg from a
| domesticated ferret."
|
| Which is kind of interesting, because domesticated ferrets are a
| different species. (I wonder if this means the clones have
| mitochondrial DNA from the domesticated ferret egg.)
| S0y wrote:
| I think "domesticated" in this context refers to the 24 Black-
| Footed ferrets they initially captured.
|
| "officials captured 24 ferrets and started a breeding program."
| Keysh wrote:
| Those would be "captive" ferrets, not "domesticated" ones.
| (They want to introduce the offspring from the breeding
| program into the wild, and have in fact done this for about
| 10,000 offspring.)
|
| This article in _Science_ about the first cloned black-footed
| ferret (https://www.science.org/content/article/conservation-
| first-c...) specifically says, "Cloning endangered species
| faces unique ethical questions, as well. One is whether the
| clone, which can hold trace DNA from its surrogate mother, is
| actually the same as the species that researchers are trying
| to save. For example, black-footed ferret clones are created
| using eggs from domestic ferrets, meaning they carry that
| species' mitochondrial DNA, which is left in the egg after
| its nucleus is extracted."
|
| (Later in the article: "... apart from her mitochondrial DNA,
| most of which comes from her domestic mother, genetic
| analysis shows she is 100% a blackfooted ferret".)
|
| "Domestic ferret" refers to the domesticated European polecat
| (e.g., https://www.inaturalist.org/taxa/399272-Mustela-furo).
| patall wrote:
| They do have domestic ferret mitochondria. The plan is to breed
| them, take only the male offspring, an cross those back into
| the original population (and thus get rid of the domestic
| heritage again).
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