I'm not sure how much of a "plot twist" this is - when I took my biology course decades ago, it was explained to me that both maternal and paternal mitochondria were passed on, but the Egg is so much larger than the sperm, that the impact of of paternal mitochondria, and amount passed on, was relatively minor. I guess the interesting detail here is that the amount present raises to the level of catching a DNA scan.
I agree. However, it can be hard to observe, even in the large, public sequencing data that is currently available. There is a large amount of mtDNA inserted into the nuclear genome, and this can make it appear that there is rampant heteroplasmy until you control for it. The actual contribution is extremely hard to observe.
"It’s not clear why mtDNA prefers being exclusively maternal"
Wait... I thought that the reason mtDNA came from your mother is that the egg from your mother forms your first cell and the sperm only delivers DNA into the nucleus. They cytoplasm all comes from your mother. In that cytoplasm swims your mother's mitochondria.
I assumed when I started reading this article that maybe somehow mitochondria from the sperm sneaks out into the cytoplasm of your initial cell.
Aside: this question came to mind today, is there any discernible genetic component from a surrogate mother (a womb donor, as it were)? It seems highly likely to me a priori?
Certainly an epigenetic contribution. It turns out that the mother's body during pregnancy can have a huge and heritable impact on the baby. E.g., studies have shown that nutritional problems (like famine) during pregnancy can cause the baby to have obesity problems later in life. These have been shown to be the result not of direct genetics (the fetus's DNA has already been selected), but by causing a different mix of genes to be expressed.
That shouldn't be too surprising. It seems logical that evolution would find a way to prepare a baby to be born into an highly-food-constrained environment so their metabolism will be more conserving of resources.
What really is surprising (at least to me) is that the child's propensity has been observed to be passed down even to the grandchild.
Yes, it is very easy to identify paternal mitochondrial inheritance in the current era. The catch is that a very low proportion of the population has mitochondrial genomic sequencing (currently). Typically, those who do have their mitochondrial genomes sequenced are those who are suspected of having mitochondrial disease and the prevalence of mitochondrial disease is very low. Of those who are sequenced, the overwhelming majority will have a mutation, that if inherited, is from the mother. I should also add that there are many 'common' mutations that cause the majority of mitochondrial disease and, as expected in a clinical diagnostic setting, these are the most frequently observed and identified molecular diagnoses. Paternal inheritance of mitochondria harboring a disease-causing mutation represents an extraordinarily rare etiology for an already very rare disease.
I work as a software developer at a DNA analysis company with an in-house lab. You might be surprised to know how much knowledge is regurgitated and how little actual research occurs.
This has been known for a long time. It's a myth that mtDNA only comes from the mother and was based on a misreading of an old paper decades ago. I don't know why the myth has so much traction among geneticists who should know better. Many claims have been made deriving from these assumptions. Nearly all research purporting to date past branches of populations based on mtDNA mutations by assuming a maternal clone is passed, and any differences are mutations, is completely off. All that research is and always has been invalid.
> Nearly all research purporting to date past branches of populations based on mtDNA mutations by assuming a maternal clone is passed, and any differences are mutations, is completely off. All that research is and always has been invalid.
This is a drastic and totally implausible statement that is not supported by any serious geneticist, nor by the Wikipedia article you've linked to.
mtDNA does not have to come exclusively, 100%, no-exceptions-ever from the mother, in order for population research which uses to be valid! 99% is quite sufficient. It is at least 99.9% accurate: as the Wikipedia article helpfully points out, there are 1000x as many mitochondria in an egg as in a sperm.
[+] [-] ghshephard|7 years ago|reply
[+] [-] ArchTypical|7 years ago|reply
I was taught differently in 1998.
There was the press coverage of: https://en.wikipedia.org/wiki/Lucy_(Australopithecus) which was referenced in a scene of https://www.imdb.com/title/tt2872732/
It can be said that it's a plot twist that was stoked for decades.
[+] [-] eridan2|7 years ago|reply
[+] [-] josephpmay|7 years ago|reply
[+] [-] eggie|7 years ago|reply
[+] [-] unknown|7 years ago|reply
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[+] [-] crusso|7 years ago|reply
Wait... I thought that the reason mtDNA came from your mother is that the egg from your mother forms your first cell and the sperm only delivers DNA into the nucleus. They cytoplasm all comes from your mother. In that cytoplasm swims your mother's mitochondria.
I assumed when I started reading this article that maybe somehow mitochondria from the sperm sneaks out into the cytoplasm of your initial cell.
Is that understanding not correct?
[+] [-] pbhjpbhj|7 years ago|reply
[+] [-] CWuestefeld|7 years ago|reply
That shouldn't be too surprising. It seems logical that evolution would find a way to prepare a baby to be born into an highly-food-constrained environment so their metabolism will be more conserving of resources.
What really is surprising (at least to me) is that the child's propensity has been observed to be passed down even to the grandchild.
[+] [-] matt4077|7 years ago|reply
BUT: the microbiome, as well as the immune system, are closely linked to the “physical” mother.
[+] [-] bookofjoe|7 years ago|reply
[+] [-] amelius|7 years ago|reply
[+] [-] abcc8|7 years ago|reply
[+] [-] inetknght|7 years ago|reply
[+] [-] sigstoat|7 years ago|reply
[+] [-] droithomme|7 years ago|reply
1996 paper on paternal mtDNA inheritance: http://www.pnas.org/content/93/24/13859.full
2002 paper on paternal mtDNA inheritance: https://www.newscientist.com/article/dn2716-mitochondria-can...
Wikipedia's been updating this article since 2006: https://en.wikipedia.org/wiki/Paternal_mtDNA_transmission
[+] [-] samatman|7 years ago|reply
This is a drastic and totally implausible statement that is not supported by any serious geneticist, nor by the Wikipedia article you've linked to.
mtDNA does not have to come exclusively, 100%, no-exceptions-ever from the mother, in order for population research which uses to be valid! 99% is quite sufficient. It is at least 99.9% accurate: as the Wikipedia article helpfully points out, there are 1000x as many mitochondria in an egg as in a sperm.
[+] [-] JohnJamesRambo|7 years ago|reply
[+] [-] iscrewyou|7 years ago|reply
1. https://news.ycombinator.com/item?id=18405636
[+] [-] robsanchez1954|7 years ago|reply