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Turns Out Mitochondria Can Come From Fathers Too (popularmechanics.com)

Posted by BeauHD on from the unsettled-science dept.

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.

64 comments

  1. Oops by olsmeister · · Score: 4, Insightful

    There's been a ton of science done with the assumption that mitochondria comes only from the mother that may need to be revisited, including the idea of a Mitochondrial Eve.

    1. Re:Oops by Anonymous Coward · · Score: 1

      *Will* need, not may need.

    2. Re:Oops by mentil · · Score: 2

      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.

      --
      Corruption is convincing someone that the selfless ideal is the same as their selfish ideal.
    3. Re:Oops by Can'tNot · · Score: 5, Insightful

      No, "may" is correct. Never assume that a popular-science article about a single research paper is the end of the story.

    4. Re:Oops by sjames · · Score: 1

      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.

    5. Re:Oops by gravewax · · Score: 2

      It is only a *Will* if the science is confirmed. At this point it is a definitely *may*

    6. Re:Oops by Michael+Woodhams · · Score: 4, Informative

      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.

      --
      Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
    7. Re:Oops by Sique · · Score: 1

      Forensics don't use mtDNA, except to find relatives. With mtDNA, you can as a maximum prove that some people are not related, which in the most cases exonerates the defendant in a criminal case. So I doubt this will change the outcome of many cases.

      --
      .sig: Sique *sigh*
    8. Re:Oops by Sique · · Score: 2

      As far as I can tell from the original PNAS article, they found evidence of two sets of mtDNA (parental and maternal), but no recombination in a single mitochondrium.

      --
      .sig: Sique *sigh*
    9. Re:Oops by Anonymous Coward · · Score: 0

      From the paper I get the sense that the cases of paternal mitochondria are always associated with heteroplasmy. Recombination between organelles from different lineages is very rare. So couldn't biparental inheritance be detected in sequencing? If cells contain two strands of mtDNA that are totally different (as opposed to heteroplasmy from recent mutations), then one of them is probably from the father.
      I wonder if a heteroplasmic mother/father could pass on more than one type of mtDNA to a child. That would make it more complicated.

    10. Re:Oops by SqueakyMouse · · Score: 1

      Well it had a silly name anyway. Eve wasn't the matrilineal most recent common ancestor in the bible. That was Noah's wife, Naamah, so she would be the appropriate biblical analogue.

    11. Re:Oops by Anonymous Coward · · Score: 0

      Interesting. No argument, but! The article forgets history. Only three families? Someone needs to remove their blinders.
      Say, a male and a female give birth, the offspring is only you and the female? No, it is a combination of the males past and the females past. And that can be traced. The male side includes the mother's tree, just as the females side includes the father's tree. There is no imacculate conception. Only leftovers.

    12. Re:Oops by Anonymous Coward · · Score: 0

      Well it had a silly name anyway. Eve wasn't the matrilineal most recent common ancestor in the bible. That was Noah's wife, Naamah, so she would be the appropriate biblical analogue.

      Except for wives of Shem, Ham, and Japheth.
      "In the selfsame day entered Noah, and Shem, and Ham, and Japheth, the sons of Noah, and Noah's wife, and the three wives of his sons with them, into the ark"
      Genesis 7:13

    13. Re:Oops by keltor · · Score: 1

      This is totally not evidence of a need to re-write mtDNA genetics. It is going to still only matter for the rare people with heteroplasmy. It's of limited scope.

    14. Re:Oops by keltor · · Score: 1

      Genesis is not describing all people on Earth. It's about the history of the Israelites and the story of how they came to be. If you're really bothered by the name Mitochondrial Eve, you can easily just go with mt-MRCA instead. It's more common in genetics articles anyways.

    15. Re:Oops by Luckyo · · Score: 1

      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.

    16. Re:Oops by Anonymous Coward · · Score: 0

      How does Lilith Adam's first wife play into this.

    17. Re: Oops by K.+S.+Kyosuke · · Score: 1

      He was talking about revisiting.

      --
      Ezekiel 23:20
    18. Re:Oops by SqueakyMouse · · Score: 1

      Oh that's right. I must have been thinking of Terminator Genisys. John Connor didn't have a wife in that one.

    19. Re:Oops by Aighearach · · Score: 1

      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 that contradicted the assumptions baked into your conclusions.

    20. Re:Oops by Aighearach · · Score: 1

      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 perfect tense, or some continuous tense.

    21. Re:Oops by Aighearach · · Score: 1

      Sorry, that should have been "individual assessment of the current state of consensus" at the end.

    22. Re:Oops by Aighearach · · Score: 1

      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.

      Claims with more balanced assumptions are less prone to catastrophic failure.

    23. Re:Oops by Aighearach · · Score: 1

      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.

    24. Re: Oops by Anonymous Coward · · Score: 0

      yes and you don't need to revisit till it is confirmed, though you can start it isn't necessary at this point.

    25. Re:Oops by fafalone · · Score: 2

      Not only will they not revisit old cases, prosecutors and the 'Justice' Department are fighting like hell to not even stop using long-discredited bunkum in trials going forward. That was one of the first DOJ actions under Trump/Sessions, to disband a recently formed committee attempting to ensure valid science in trials.

    26. Re: Oops by K.+S.+Kyosuke · · Score: 1

      Quite the opposite, you can't confirm the idea without revisiting the idea first.

      --
      Ezekiel 23:20
    27. Re:Oops by Michael+Woodhams · · Score: 1

      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 proportion of the two alleles will randomly shift. The smaller the bottleneck, the greater this random change will be.

      I'm a coauthor on some papers looking at mitochondrial heteroplasmy where I was doing the maths to figure out the size of this bottleneck. (In penguins, about 30, in salmon, about 100 - but uncertainty was quite large, I think about 30%.) As I recall, different organisms can have quite different bottleneck sizes, and I think human bottleneck is quite small. (I haven't looked this up, so don't rely on it.) This means it would likely be only a few generations before the heteroplasmy resolved itself (one of the alleles would 'fix')

      Modern sequencing techniques could not only very accurately measure the heteroplasmy proportions, it could also detect whether some sequences had undergone recombination, as it can give separate reads of thousands of individual DNA strands. The data I was working with used older 'Sanger' sequencing and could only give approximate averages over many strands.

      --
      Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
    28. Re: Oops by Anonymous Coward · · Score: 0

      completely incorrect. First you verify the current scientific data from this lot, THEN you can revisit the other related research. The two are separate pieces of work, the revisit is only necessary once confirmed.

    29. Re:Oops by Agripa · · Score: 1

      As far as I can tell from the original PNAS article, 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. Since the female made a larger contribution with a larger egg and perhaps other greater investments, it makes sense that she would win this war anyway.

  2. Qui-Gon Jinn turns and says: by fahrbot-bot · · Score: 1

    A group of researchers found three unrelated families where individuals had mitochondrial DNA from both parents.

    Hmm ...

    --
    It must have been something you assimilated. . . .
    1. Re:Qui-Gon Jinn turns and says: by goose-incarnated · · Score: 2

      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?)

      --
      I'm a minority race. Save your vitriol for white people.
    2. Re:Qui-Gon Jinn turns and says: by Applehu+Akbar · · Score: 1

      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.

    3. Re:Qui-Gon Jinn turns and says: by keltor · · Score: 1

      Nobody ever knows for sure. Recombination is a thing with all of the DNA except for Y-DNA and mt-DNA. Even in this circumstance they didn't find mt-DNA recombination. (Finding that would make this 10000000000x bigger discovery.)

    4. Re:Qui-Gon Jinn turns and says: by keltor · · Score: 1

      This particular thing isn't NEARLY as extraordinary as it seems as the discovery is just related to people with doubled organelles, a rather rare condition. (That in many circumstances leads to early death and infertility.)

    5. Re:Qui-Gon Jinn turns and says: by Anonymous Coward · · Score: 0

      It could be a new Genetic mutation.

  3. Mitochondria by Anonymous Coward · · Score: 1

    Well how else would it explain that Luke got force powers?

    1. Re:Mitochondria by Aighearach · · Score: 1

      It could even explain the Evil Spiderman Suit.

  4. Re:This is why by mentil · · Score: 1

    My sky god can beat up your sky god! /s

    --
    Corruption is convincing someone that the selfless ideal is the same as their selfish ideal.
  5. Affected? by Anonymous Coward · · Score: 0

    Is that pathological?

  6. Article Leaves Out Information by Wheaty13 · · Score: 5, Informative
    The article is making suggestions while leaving out important information to try to make it seem like this could be common when the data does not support that conclusion.

    I believe a better source can be found on Blaine Bettinger's blog https://thegeneticgenealogist.com/2018/11/26/can-mtdna-really-come-dad/

    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:"

    1. Re:Article Leaves Out Information by Michael+Woodhams · · Score: 1

      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 nature.)

      I'm at home, so I don't have institutional access to read the paper, but from the abstract and the blog post above, it looks like an exciting result - just not as exciting as the media reporting makes out. This is like finding a species suspected to have been extinct for a few decades, rather than being like finding the Loch Ness Monster.

      --
      Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
    2. Re:Article Leaves Out Information by RockDoctor · · Score: 1

      This is like finding a species suspected to have been extinct for a few decades,

      ... which has happened several times this year.

      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 difference.

      It's news, but not big news.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  7. The farce is strong with this one by Jogar+the+Barbarian · · Score: 2

    Please tell me I wasn't the only one who read that as "midichlorians".

    --
    3. Profit!
    2. ???
    1. On Soviet Slashdot, a Beowulf cluster of alien Natalie Portman overlords welcomes YOU!
    1. Re:The farce is strong with this one by Anonymous Coward · · Score: 0

      Please tell me I wasn't the only one who read that as "midichlorians".

      Make that at least two of us.

  8. Re:This is why by Waffle+Iron · · Score: 1

    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?

  9. Re:This is why by Anonymous Coward · · Score: 0

    Religion is not science. It is faith - anti-science.

    Every scientific argument against a religion can be countered by a simple statement: "God(s) made it that way." It is impossible to disprove.

    Scientists that get involved in arguing religion are idiots. It's like trying to produce objectively "good" art. You can't argue with the pigs, and just just end up covered in mud for trying.

  10. Re:This is why by ArhcAngel · · Score: 1

    I am saying if you claim to cling to the scientific method and turn around and sat batshit crazy things you are a liar.

    --
    "A person is smart. People are dumb, panicky dangerous animals and you know it." - K
  11. Damn Lucas... by Anonymous Coward · · Score: 0

    I totally read "midi-chlorians".

  12. GET OUT RETARD ANTI-SCIENCE REPUBLICAN CHILD by Anonymous Coward · · Score: 0

    "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!" If you lying fagbots don't learn to quote people better, you'll never reach stage II troll, Ivan.

  13. Re:This is why by Waffle+Iron · · Score: 1

    OK... but WTF does that have to do with mitochondria?

    And who said anything that was "batshit crazy"?

  14. Re: This is why by Anonymous Coward · · Score: 0

    It is firmly settled, water is h2o.

    Yes, I know, some bastard will say 'what about Heavy Water'...

  15. Re: This is why by Anonymous Coward · · Score: 0

    It is firmly settled, water is h2o. Yes, I know, some bastard will say 'what about Heavy Water'...

    But you did not see this one coming: "Is Water H2O? Evidence, Realism and Pluralism" by Hasok Chang (2012).

  16. Georgia Purdom by AndyKron · · Score: 1

    Answers in Genesis is going to have a field day with this. They will, of course, be wrong.

  17. Soccer Dad by Anonymous Coward · · Score: 0

    This must happen when the Father is the sort of person that plays Soccer.

  18. Re: This is why by Anonymous Coward · · Score: 0

    Crom laughs at your sky God.

  19. Re: This is why by Anonymous Coward · · Score: 0

    Heavy water is still H2O.

  20. Interesting. by Anonymous Coward · · 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 of humans.

  21. Relationships by Anonymous Coward · · Score: 0

    The families may be unrelated, but how unrelated were the parents in each family?