# How did mitochondria become part of our DNA? **URL:** \ **Category:** Factual Questions\ **Created:** [June 9, 2016, 6:11pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939 "2016-06-09T18:11:29Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 10, 2016, 3:39pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/21 "2016-06-10T15:39:23Z")
> [@Qadgop\_the\_Mercotan](#): > > **Radiolab** did a thing on this very [topic](http://www.radiolab.org/story/cellmates/). It raises the point that prokaryotes existed for 2 billion years before this development occurred, allowing the development of eukaryotic cells, organisms, etc. And ponders just how unlikely this random event was. Stephen Jay Gould contended that this was the most difficult step in the evolution of multicellular life, based on how long it took to occur. Bacterial life seems to have appeared almost as soon as conditions on the early Earth had stabilized enough for it to be possible, while eucaryotes took a very long time to appear. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [June 11, 2016, 12:15am UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/22 "2016-06-11T00:15:21Z")
> [@Qadgop\_the\_Mercotan](#): > > **Radiolab** did a thing on this very [topic](http://www.radiolab.org/story/cellmates/). It raises the point that prokaryotes existed for 2 billion years before this development occurred, allowing the development of eukaryotic cells, organisms, etc. And ponders just how unlikely this random event was. Well that settles it. It just _had_ to be intelligent design! No doubt about it! ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [June 11, 2016, 2:52am UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/23 "2016-06-11T02:52:43Z")
> [@Senegoid](#): > > Well that settles it. It just _had_ to be intelligent design! No doubt about it! That is the argument of a lot of religious folks, to be sure. Me, I just tend to think that complex, multi-cellular life is going to be a lot rarer in this universe than many folks think. Sadly. ---
**Author:** ![alsoknownas](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@alsoknownas](https://boards.straightdope.com/u/alsoknownas)\ **Post date:** [June 11, 2016, 9:46am UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/24 "2016-06-11T09:46:21Z")
Wow, that does make it seem as though bacteria-style life is likely to be commonplace though, no? ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [June 11, 2016, 12:32pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/25 "2016-06-11T12:32:05Z")
> [@mr\_wolf](#): > > A while ago there was an attempt to pass, in the UK parliament, an act that would allow genetic engineering in human subjects. The ‘for’ camp defended the motion saying that the alterations would be on mitochondrial DNA and not human. Unfortunately nobody saw beyond this little gimmick or at least refuted it with the obvious argument Colibri just laid out. Well, at the risk of hijacking, it wasn’t quite that simple: the argument was mostly that it has nothing to do with our personality or individual characteristics and was just giving people with defective mitochondria a similar strain as any healthy person. To me it would be perverse if we did not make such a correction on the basis of “Sorry, slippery slope, if we help you, we’ll inevitably try to make a human t-rex”. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 11, 2016, 2:08pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/26 "2016-06-11T14:08:53Z")
But the event can’t have been _too_ unlikely, can it, given that almost the same thing also happened with the chloroplasts. If one cell absorbing another and turning it into an organelle had happened only once in history, then yes, maybe it was a fluke. But we know that it happened at least twice, which makes it sound a lot less fluky. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [June 11, 2016, 3:12pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/27 "2016-06-11T15:12:47Z")
> [@Chronos](#): > > But the event can’t have been _too_ unlikely, can it, given that almost the same thing also happened with the chloroplasts. If one cell absorbing another and turning it into an organelle had happened only once in history, then yes, maybe it was a fluke. But we know that it happened at least twice, which makes it sound a lot less fluky. Twice in about 2 billion years, instead of once, then. I like those odds a lot better! ---
**Author:** ![Blue\_Blistering\_Barnacle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blue_blistering_barnacle/32/3386_2.png) [@Blue\_Blistering\_Barnacle](https://boards.straightdope.com/u/Blue_Blistering_Barnacle)\ **Post date:** [June 11, 2016, 3:50pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/28 "2016-06-11T15:50:05Z")
I suppose that the first cell to take up a chloroplast was already a eukaryote (and may have been predisposed, having done the trick once already). There are several diseases caused by organisms (bigger than viruses) which are obligate intracellular parasites. I guess if one of those confers a benefit, we could see it happen again. Probably this explains all those Marvel mutants. ---
**Author:** ![mr\_wolf](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@mr\_wolf](https://boards.straightdope.com/u/mr_wolf)\ **Post date:** [June 11, 2016, 5:03pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/29 "2016-06-11T17:03:53Z")
> [@Mijin](#): > > Well, at the risk of hijacking, it wasn’t quite that simple: the argument was mostly that it has nothing to do with our personality or individual characteristics and was just giving people with defective mitochondria a similar strain as any healthy person. > > To me it would be perverse if we did not make such a correction on the basis of “Sorry, slippery slope, if we help you, we’ll inevitably try to make a human t-rex”. Yes, it was this kind of shortsightedness I heard on that session. Of course any human genetic engineering proposal will have at least one positive effect and what their proponents usually do is to put it at its forefront. Why do principles matter? So we don’t get to the seconds and thirds. Is it a slippery slope? Maybe it isn’t. Then again it might. Do you have a rough idea of how much profit anti-genetic engineering legislation is wasting annually? “nothing to do with our personality or individual characteristics”. Surely this was an unpolished thought? Even just bypassing what has been said on this thread, would that be a demarcating line for you? “Personality” is an awfully subjective term. So are “healthy” and “defective” as far as hereditary characteristics are concerned. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 11, 2016, 5:15pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/30 "2016-06-11T17:15:54Z")
> [@Chronos](#): > > But the event can’t have been _too_ unlikely, can it, given that almost the same thing also happened with the chloroplasts. If one cell absorbing another and turning it into an organelle had happened only once in history, then yes, maybe it was a fluke. But we know that it happened at least twice, which makes it sound a lot less fluky. As has been pointed out, although the trick has been done twice, it was by the same kind of organism. The eucaryotes which acquired chloroplasts had already obtained mitochondria (presumably). The events weren’t independent. ---
**Author:** ![Vicsage](https://avatars.discourse-cdn.com/v4/letter/v/e68b1a/32.png) [@Vicsage](https://boards.straightdope.com/u/Vicsage)\ **Post date:** [June 12, 2016, 9:15pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/31 "2016-06-12T21:15:00Z")
How similar is human mitochondria to that of a dog, for example? And have they ever tried to replace the mitochondria from one species into an egg cell of another then see what happens? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 12, 2016, 9:29pm UTC](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939/32 "2016-06-12T21:29:18Z")
**mr wolf** , those same arguments could be applied to _any_ medical procedure at all. If we compromise our principles enough to allow penicillin, then where do we stop? It’s not enough to just have principles. You need to have principles that make sense. And if the only reason you can find to oppose something is “it offends my principles”, then maybe it’s time to rethink your principles. [Previous page](https://boards.straightdope.com/t/how-did-mitochondria-become-part-of-our-dna/756939.md?page=1)