Chromosome (24) mtDNA - Lynn Margulis and the mitochondrial DNA
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- Опубликовано: 22 дек 2013
- EXPLORE THE RI ADVENT CALENDAR: rigb.org.uk/advent
When we're born we usually inherit our father's surname but we also inherit a rather unique type of DNA from our mothers -- mitochondrial DNA. Aoife McLysaght explains how this special genetic link can be traced back to the origins of humans, and tells the story of the remarkable female scientist who figured out where our mitochondria came from in the first place.
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Lynn Margulis "never had an issue with her gender in science" ... In her own words!!
Yes, I also noticed the straw man argument. In fact Lynn explicitly states that she had no issues with sexism.
What a fine ending for a great series. There are many genes on each chromosome, so I am expecting a second season next year. Am I right?
Here is Lynn's original paper. She was married to Carl Sagan at the time, so published as Lynn Sagan.
www.gps.caltech.edu/classes/ge246/endosymbiotictheory_marguli.pdf
Thanks to @Tucker303 on twitter for the link.
Thanks for the video and the link to the original article.
easy to understand. Thank YOU.
I love that cute mitochondria doll. Where can I get it?
This is amazing! gave me goosebumps!!
1:08 "everything except bacteria"
And archaea!
You're right, of course, and I anticipated that someone would come up with this comment. I agonised over this a bit. I justified saying "bacteria" because they used to be called "eubacteria" and "archaebacteria" and also because explaining the distinction between bacteria and archaea would be another video in of itself. I decided that for people who don't already know what a eukaryote is, the "everything except bacteria" explanation was a good enough (not perfect) explanation. For people like you and me, who already know about eukarya, archaea and bacteria, the explanation isn't needed, but for those who don't know I made the decision to simply because it wasn't the main point of the video.
For the record, and on a more pedantic point, it also grated with me to say mitochondria instead of mitochondrion and bacteria instead of bacterium for the singular! :-)
Fair point :)
Mitochondrion and bacterium doesn't really bother me, since my native language doesn't use those suffixes, with a few exceptions like virus/vira.
Indeed. Even more since it is now suspected that eukaryotes happened within archaea (and not in parallel) www.nature.com/nature/journal/v504/n7479/full/nature12779.html
In fact, there are also the unicellular eukaryots without mitochondria.
Loved the video
The animation movie showed a double membrane bacteria being endocytosed by the eukaryot. Was it a mistake? I always thought (learnt) that the outer membrane of mitochondria came from the host cell.
+Nicolas Le Novere Prokryote cells have been shown to retain membranes of protist cells they form endosymbiotic relations with.
Thanks that was really good
“Aoife McLysaght explains how this special genetic link can be traced back to the origins of humans”.
Actually this traces back to ONE woman! I.e. every living person is descended from the SAME one woman!
Excellent explanation.
Thank you for the video
The brilliance of women!
Margulis didn't get pushback because she was a woman, even she stated that she didn't really experience sexism, she got resistance because symbiont theory was considered pretty radical at the time, at least in western science.
Margulis stated that much the basis of her work comes from Russian scientists from the early 20th century who just didn't have a way to test their hypotheses.
Great video. Thank tou
Symbiosis occurring on many Biological levels. Fascinating.
Excellent information..thank you
3:42 If mitochondrial DNA is inherited intact down the ancestral line, how did it originate? Its amazing how it has the ability to reproduce this coding. Seems like it always had the ability to do it too me.
It’s clear all us humans descended by one Mother of all. In fact, I wouldn’t be surprised if that fist female was able to reproduce by parthenogenesis. Then evolution took place in finding it good to evolve a male.
Wasn't Margulis odd personality and many strange beliefs (that germ theory is false for instance) more important in her ideas being rejected than her gender?
Actually there is 24 and 25 because they discovered that mitochondria are not inherited from mothers only but also from fathers. Check the principle of "Heteroplasmy" and see how there are different sequence of mtDNA in same cells of patients of lets say a mitochondrial disease like LHON (Leber Hereditary Optic Neuropathy)
Brilliant !
Great music.
What u used to made it
thanks
That's where that Adam's rip went.
So, mtDNA only evolves by pure chemical mutation as it splits?
So, does that mean its not really changed much in a billion years, other than being a better 'good' symbo parasite?
Does mtDNA look pretty much identical across all other living animals?
mtDNA evolves pretty quickly. Apart from recombination with DNA from other lineages, all the usual processes of evolution apply. Also, because only half the population can pass on their mtDNA (i.e., females) the "effective" number of mt genomes is half that of other DNA. Small numbers lead to faster evolution because unlikely things are more likely (think of the chances of getting all heads if you toss a coin five times vs the chances of getting all heads if you toss a coin 500 times).
So, in answer to your question, no the mtDNA isn't identical in all animals, but there are recognisable similarities, as there are for other regions of DNA.
Aoife McLysaght Also, mtDNA doesn't have quite the same repair mechanisms as nuclear DNA.
It's a shame there are so many men who still feel personally attacked when gender biases etc are mentioned. It's a significant part of the picture, it really doesn't need to get your back up. Jesus.
I'm disturbed by the phrase "proven true". Sure, her theory has been corroborated by evidence, but you can never "prove" anything in science, only confirm for the time being. I thought the RI would know better than that.
WHAT I LEARNED IN SCHOOL IS
Great video, but with an unfortunate and misplaced "explanation" that Margulis' proposal was opposed due to her gender.
Lovely!
i enjoyed this one and was not offender by the sleight after all i have lived thru gemain greer and it has not affected me or my reindeer ok i know rudolfs a girl!!!!
I've been a fan of Lynn Margulis from first hearing of her ideas (her book Microcosmos written with her son). So, it should be no surprise that I very much like this little video and its presentation and its presenter. Well done!
Great video. I have a question: What happens with the sperm mitochondria in in vitro fertilization? Do they get integrated in the new being? Thank-you.
There are no sperm mitochondria.
Finallyatheist are you sure? All cellular processes burn ATP and mitochondria synthesize ATP. so for that tail of the sperm cell to work it has to use ATP and a lot of it. Where is it getting that energy for cellular respiration? It has to have a mitochondria.
I know it was a nervous slip, but it is not "a mitochondria", but "a mitochondrion". Also, it wasn't just one proto-animal cell and just one procaryote (blue-green respirating spirochete) that established an endosymbiotic relationship. This happened millions or billions of times due to environmental atmospheric pressures-the era of Stromatolites and infusion of oxygen into the atmosphere 1.5 billion years ago.
And yes, this is a fact. Mitochondria were once free-living, respiratory, aerobic prokaryotes (true bacteria). Check out their bacterial chromosome consisting of 16,569 base pairs encoding for 37 genes.
from Germ Theory to Gravity, all theories are challenged when proposed, and could be called "slow to gain acceptance." There is no evidence in this video to support the claim that the gender of the scientist was a detriment to her success.
She looks just like Anna Duggar! Maybe they're related? Investigate!
McLysaght says that Margulis' theory was rejected (at first) because she is a woman but doesn't offer any evidence to back up that claim. Most radical ideas whether from a man or a woman are rejected at first. "Tenacity" of the scientist should NOT bring about a change, but offering supporting evidence does. Dr. Margulis spent years providing enough evidence to support her idea, which is now accepted.
Hi James, we actually say that "it's disappointing to 'think' that the reason it wasn't accepted..." is that she was a woman. We suggest this, rather than state this as a 'fact' or as the ultimate reason it failed to gain traction.
As for the comment on her 'tenacity' - I do agree with what you say, tenacity alone should not push a theory through, but it is definitely a required trait when facing such fierce opposition. She must be commended, in part, for her personal courage in championing this idea.
It would be interesting to ponder the case, if a more senior (perhaps male) scientist had proposed the same theory at the time - would it have gained wider acceptance more rapidly and / or would it have required the same burden of proof?
I think it's important to highlight the fact that science - although it attempts to free itself from the bias of its human purveyors - can never exist in a social or cultural vacuum. Its development and progress is very much shaped by the same factors (funding bias / gender bias) that influence most other strands of our society. So in part we thought it was important that this video highlighted such things, rather than say just presenting a 'straight' explanation of the mitochondria.
Anyway, have a happy new year!
*****
Thanks for the reply. It _is_ sad to think that gender bias still exists in the sciences.
@@EdProsser I’m just surprised they didn’t want to steal her proposed theory, like most males did with female inventions.
So does this mean their is no more Eve...because if we come from Adam and Eve we should all have Eve's mitochondrial dna.
Remember this story was just another creation myth, all cultures have them. But there was a "mitochondrial eve" a common female ancestor.
@@AsFewFalseThingsAsPossible 😷😷 2020 👍👍
Marvellous what thoeries can be accepted as fact, as long as a creator is ruled out of any equation.
As it should be by anyone who is out of kindergarten.
Why is this about woman's history I'm just tryna learn biology
So the BLACK WOMEN STARTED THE Eve gene ?? GOT IT🤔👍🏾
It took less time for Lynn Margulis theory on mitochondria to be accepted than the time that it took for Barry Marshall to be accepted on his theory of H. pylori causing ulcers. It was peer review that took time not her gender! Even she bristled at the thought that her gender was ever an issue in science.
Lynn Margulis never cited being a woman as contributing to her challenges in being accepted academically.
She doesn’t need to. Imagine if she did too? She would be made a laughing stick and not believers. Especially by men.
first thought: huh o.o 24 ?
so are we getting a 25 one?
You'll be getting the Christmas Lectures :-) www.rigb.org/christmas-lectures
Well i hate to burst your bubble, but a paper published in Nature Genetics 15 in 1996 by Parsons, where a study was done on the substitution rate (mutations) and how often they occured in the mtDNA where they expected to find the "nearest common ancestor" to be about 150,000 y.a.. What he found was that mutations occur much faster and that mtEve was only 6500 yrs old. The "proof' of what you speak is purely deceptive. Because things have the same building blocks to begin with in no way indicates they came from the same thing. How then do you explain the ATP synthase? As you know it produces ATP. But what was required to build such a thing as the ATPsynthase? None other than ATP itself.
But correlation does not imply causation, just because something is similar doesn't make it proof, surely? Though if true, how did the former cell function, and produce ATP?
You're asking more than one question, and there isn't space to properly reply, but here's a quick response.
Generally, this is a huge area and there is a vast literature on this. Hopefully, this video served to pique your interest, and you might decide to read more about it.
I mention the similarity of the DNA sequence of the mtDNA with another bacteria (alphaproteobacteria). This is evidence of evolutionary relationship, and shows that the DNA of the mt is not just a derivative of the nuclear DNA, but is distinct.
As for how the cell operated prior to the mitochondrial endosymbiosis, well bacteria and archaea do that all the time. Specifically, how the cell that ended up becoming the eukaryotic cell might have worked is discussed in the Hydrogen Hypothesis en.wikipedia.org/wiki/Hydrogen_hypothesis
Happy reading! :-)
Correlation vs Causation does not apply here, you're thinking of a fallacy applied to statistics.
It is used to describe the fallacy that because two variables "move together" (i.e. show correlation, or "association" as it is properly called), it is commonly assumed that they must be dependent of each other, or caused by one another.
The short answer to your question is that has nothing to do with biology.
As Dr McLysaght replied, this is a very well researched topic. For my simple explanation, all cells can change foodstuff into energy, but mitochondria do it much more quickly and efficiently.
You cannot have causation without correlation. That said, what are you even talking about?
Oh beautiful!
I know some have commented previously and have been severely socially chastised for it but I must agree with some of the sociology-political irrelevant details contained within this'.
I fail to understand the scientific relevance of the gender/colour/creed of whomever makes a discovery that leads to the furthering of our knowledge. Does that person deserve respect. Yes.
Whilst the plight of Margulis may indeed provide an interesting topic it should be dealt with outwith objective science. Her discovery was indeed groundbreaking and we should focus on that. Not her gender.
Political and social equality issues should be dealt with by Social scientists, politicians and debated appropriately there along with historical gender imbalance issues.Science should be about objective inquiry and the scientific method.
If every scientist decided to promote their own particular pet grievance within a scientific lecture then it would be a sad state of affairs.
Evidence of these 24 lectures shows that we are no longer holding onto those outdated values as 10 out of the 24 are hosted by women.
Perhaps that is not enough? Do we need a 50/50 gender balance along with an inclusive sexual orientation split containing individuals with national and cultural diversity and exploring an emotive back story for every scientist discussed?
This is the RI. Not X Factor.
At the fall of our society the left will be screaming “at least we had gender and race equity in all societal institutions”.
If only Galileo had had it so easy. Or Einstein and relativity, for that matter.
It would also be interesting to learn a bio-evolutionary explanation for paternal sur names, which probably stem from property, which, in turn, was a function of male physical dominance in hunter-gatherer societies wherein mothers exchanged certain powers in for protection and a home to raise their offspring. We're also learning that matriarchal hierarchies and social structures in the animal world aren't so gentle (etc.), on land or sea. As for the use of patrilineal surnames, that's a fairly recent practice, and the names were often tied to place or the father's trade. But why "John's son" and not Jane's? Because she was a baby-making cypher.
0.1
Very annoying music. Why should everyone who watches this associate mitochondria haplogroups with that cheery tune? Very poorly thought out and edited. And I was expecting to be told your mother's haplogroup, since it was mentioned at the outset. I would present this crucial information in a much more serious way, not as a factoid. The implications are yet to be uncovered, such as origin of life, or diagnosing hitherto unrecognised genetic illnesses. Serious approach for matters of importance. For anyone reading this, I'd highly recommend Nick Lane's books on the subject.
I think mitrocondrial DNA is not fully accurate to trace ancestors, since female usually do not follow men into wars in other nations. At one point, the tracing process will just stuck into same place, same nation. 🤔
Oh my Gosh! I want to learn a little about science. I don't want to be lectured to about how bad men were.
kgrgzafnkg huh?
I think you're just looking for reasons to complain, I personally found this video to be one of the most interesting of the series and I didn't even notice any anti manly man lecturing. Various types of discrimination delayed the acceptance of certain theories and I think it's relevant to mention IMHO.
Bach Irontzki oh
ha!
Ok, my first reaction is always very snarky in these situations, but I would really like to know what your opinion is on sexism in science. Do you think it exists? Is it towards men or women or both?
@ 2.11, one and half billion years ago preposterous hypothesis.
Woman Rule
"one bacteria"
Ugggh!
We are all African :)
Sperm has mitochodria
Hellòoooo!, Black Widow!
It's in every biology textbook? Oh, it must be true. For something to have been "proven," it must either be observed to occur, or totally recreated in a lab environment. Did either of these things happen?
Yes, I believe this theory yes. Now we have CoronaVirus that wants to be our companion.
So, it's inherited intact. Well, that's quite a dangerous situation. If that's true. Indeed. Because, I thought that it was a mixture. Mixup. And, so we get a copy of our Mother's microcondria, so I wonder what characteristics this shows. I think it's possibly responsible for the appearance of the skin. Although, it's been explained that this part of the cells is responsible for energy levels.
That's pretty interesting. I am drawn to this lecture. It's interesting. Thanks.
Oh 39 genes, and mainly involved in production of energy. Interesting.
All humans have mtDNA from one of three haplogroups, conveniently coded L,M,N. The region of intersection of these three groups is southwest Asia. The three women who were the ancestors of these three haplogroups were the three daughters-in-law of Noah.
Dear Aoife, you should think about changing your hair style. As you have to keep stroking your neck every few seconds to take them off your eyes :-)
who here because of coronavirus
RI why are you playing Racism
Every new scientific thesis undergoes scrutiny. Theories like evolution and gravity were met with doubt by their scientific community of their time and didn’t get the recognition they deserved till much much later and they were men. The idea that it’s because she was a woman proposing a scientific thesis and that’s why she wasn’t immediately praised for her break through is mind numbingly naive. Anyone male or female who proposes a scientific thesis is met with scrutiny.
Not really. Females take a way harder hit. I mean, even with inventions they were not made to be recognized and males would just steal their work saying its theirs. Happened extremely often, what makes you think this wasn’t also one of those cases? I say she got lucky!
God
1:00 "This is a mitochondria" ??? Did you get an F in Grammar? You cant really be a scientist.
Correct: This is a mitochondrion.
Thumbs down for the noob presenter.