Turns Out Mitochondria Can Come From Fathers Too (popularmechanics.com) 64
schwit1 shares a report from Popular Mechanics: We all know: The mitochondria is the powerhouse of the cell. But the mitochondria is much more than a simple power plant. It's also a unique source of DNA that can give us important clues to our species and our history. That's because the DNA in your mitochondria comes only from your mother. At least, that's what we believed. But new research suggests that in some cases, mitochondrial DNA can be inherited from fathers, too. A group of researchers found three unrelated families where individuals had mitochondrial DNA from both parents. A total of 17 people across these three families were affected, suggesting that mitochondria aren't as exclusively maternal as scientists believed.
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*Will* need, not may need.
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No, "may" is correct. Never assume that a popular-science article about a single research paper is the end of the story.
Science isn't just about virtue signaling that you're pro-science. The details do matter.
If you know that it is now disputed, then you know that the related research will need to be revisited.
You certainly wouldn't want to be all like, "Oh, our shit might have been refuted, but maybe we won't revisit it to find out." No, you definitely have to revisit.
Revisiting your conclusions about your past results might even be a necessary predicate for it to be science; even when there wasn't additional research tha
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Science is never "confirmed" in that sort of way where the status of confirmation becomes an attribute of the theory.
Each time an experiment is repeated, a particular past result is confirmed, or not, but no state information has been added or created.
Or for English majors; scientific consensus lives only in the present simple or past simple tenses; it does not, and can not, live in the perfect tense, or in any continuous tense. However, individual assessment of the current state of assessment is in the per
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Sorry, that should have been "individual assessment of the current state of consensus" at the end.
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First thing that came to mind is that this puts a damper on the entire concept of a Mitochondrial Eve. OTOH, this info could help fill in question marks that got in the way of resolving the question once and for all.
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Not to mention forensics. The true test of "scientific evidence": will trials featuring it and resulting in a conviction be revisited if the underlying theory is disproved later? If not, it's just the local shaman throwing more expensive bones.
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Only to a limited extent. It depends on how often this happens, and whether mitochondrial recombination is a thing.
"Normal" (nuclear) DNA undergoes recombination: there are two (not quite identical) copies of the genome, and bits get swapped between the copies, so a chromosome you got from your mum has bits that came from both of your maternal grandparents.
It is hard to know whether this process also happens in mitochondria, because the mitochondrial genomes seldom differ, and when they do, it is very likely they do so at only one place. If there is no mitochondrial recombination, then all mitochondrial genomes are inherited strictly from one parent, one grandparent, one great-grandparent etc. Mitochondrial Eve holds up fine, it is just that now those mitochondrial lineages very rarely are inherited through a male. The ancestry is still strictly a tree, where a 'parent' may have multiple 'children', but a 'child' has only on 'parent'. ('Child' and 'parent' here are individual mitochondrial genomes.)
I know there is research into mitochondrial recombination, but I don't know the field well enough to comment on the conclusions of this research.
Once you have recombination, the tree breaks down, and two mitochondrial lineages can merge together into a hybrid. However, if this is very rare (as seems to be the case) then the tree rooted at Mitochondrial Eve is still a very good approximation. In particular, it is still very likely that the entire sequences of all modern human mitochondria are descended from the mitochondria of a single woman.
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As far as I can tell from the original PNAS article [pnas.org], they found evidence of two sets of mtDNA (parental and maternal), but no recombination in a single mitochondrium.
That makes sense based on why paternal mtDNA is not generally passed on.
Sperm jettison their mitochondria before fusing with the ovum but if this is incomplete, paternal mitochondria will be included but why are steps taken to preserve only one set of mitochondria?
In species where the two gametes both contribute their mitochondria, the mitochondria duke it out for who gets passed on and this process is naturally rather disruptive to the new cell so it is better to discard one set in favor of the other. Sin
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Paternal leakage would almost always cause heteroplasmy (unless the father happened to have the same mitochondrial genome as the mother.) Sequencing can indeed detect biparental inheritance.
If an individual was heteroplasmic due to paternal leakage when they were conceived, and the individual was female, she could pass this heteroplasmy to her children. There is a 'bottleneck' in mitochondrial genome number per cell, and if those genomes are randomly chosen from the mother's heterplasmic selection, the prop
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Right. You don't move immediately to rewriting.
You simply throw it away, and start fresh.
If you try to cheat and rewrite, you'll keep dragging your false assumptions and solidified conclusions along with you.
Also, remember, much of this work is based on an absolutist assumption that mtDNA can only blahblahblah. The problem with those types of assumptions, they're completely 100% refuted by a single counter-example. If it is rarely wrong, that means that in total over time, the assumption is completely wrong
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From the abstract:
>Our results suggest that, although the central dogma of maternal inheritance of mtDNA remains valid, there are some exceptional cases where paternal mtDNA could be passed to the offspring.
It may need to be revisited, but considering the way abstract talks about their findings, it would make more sense to invest time in replicating this study's results and identifying these "exceptional cases" and what causes them.
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Replicating this study would be the first step in revisiting the things it contradicts, yes.
Duh
I'm not sure why you present that as being something different. That's how the scientific process works; any new work revisits the ideas implicated by the work.
Qui-Gon Jinn turns and says: (Score:2)
A group of researchers found three unrelated families where individuals had mitochondrial DNA from both parents.
Hmm ...
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A group of researchers found three unrelated families where individuals had mitochondrial DNA from both parents.
Hmm ...
Actually raises the question: how did they know that those families where actually unrelated? mDNA from 25 generations ago when those three families were related can make its way into the current gen, no?
(Obviously, someone will post a lengthy and factually correct response to this explaining why that is not possible, right?)
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A group of researchers found three unrelated families where individuals had mitochondrial DNA from both parents.
Hmm ...
Next, we'll have to study some families outside of Kentucky. Extraordinary claims require extraordinary evidence.
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Mitochondria (Score:1)
Well how else would it explain that Luke got force powers?
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It could even explain the Evil Spiderman Suit.
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My sky god can beat up your sky god! /s
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If you ever meet a scientist who thinks somethings is finitely settled you have met a fool. We look at the universe through the eyes of our knowledge. We assume things based on that knowledge. We dismiss possibilities because we assume there isn't anything we don't know. Neil deGrasse Tyson makes fun of people who believe in an unseen entity while telling everyone we are all just computer AI programs without any proof! The irony is overwhelming!
So are you willing to allow that the it is not finitely settled whether your unseen entity even exists at all?
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OK... but WTF does that have to do with mitochondria?
And who said anything that was "batshit crazy"?
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I believe a better source can be found on Blaine Bettinger's blog https://thegeneticgenealogist.com/2018/11/26/can-mtdna-really-come-dad/ [thegenetic...logist.com]
Which includes the following:
"What is missed from the media coverage, however, is that these families were identified because member(s) were presenting with conditions that made the researchers suspect a mitochondrial disorder."
"Indeed, the paper discusses this single case, and emphasizes that many attempts in the ensuing 16 years to identify biparental mtDNA inheritance were unsuccessful:"
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I came here to point out that the summary is rather overstating the case, but your link does a much better job of it than I could.
The concept of paternal inheritance of mitochondria is sufficiently known to science that it has a term to describe it: "paternal leakage". It is something which has been observed in a number of organisms, although I think it is always rare. (As I recall, interspecies hybrids are more prone to paternal leakage, so sometimes what you observe in the lab may not be happening in natu
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Looking from the other end of the telescope, I see a situation like this : there is a process that prevents sperm mitochondria from reproducing or even surviving in the fertilized egg ; that process is a biological process ; because it is a biological process, it will not be 100% efficient (e.g. DNA replication has only about 99.99999% fidelity). Someone has found that 0.00001% of
The farce is strong with this one (Score:3)
Please tell me I wasn't the only one who read that as "midichlorians".
Georgia Purdom (Score:2)
Interesting. (Score:1)
I've "known" this for quite a while (in the amateur sense, I'm not a biologist) but I don't have the slightest idea where I picked that knowledge up. Something about a patient with some sort of metabolic mitochondrial disorder, but not one that was in his mother's lineage, and the meiotic process when sperm are created sometimes separating unevenly and you end up with a mitochondria left over in a sperm. Very rarely, but something that could and apparently does ever happen spread over the entire population