Scientists have recreated heteroplasmy by producing embryos with both maternal and paternal mitochondrial DNA:
A new study published in the Proceedings of the National Academy of Sciences (PNAS) from the University of Missouri has succeeded in creating embryos with "heteroplasmy," or the presence of both maternal and paternal mitochondrial DNA. This new innovation will allow scientists to study treatments for mitochondrial diseases in humans as well as the significance of mitochondrial inheritance for livestock.
When parents pass along their genes to their children, most of the DNA from the mother and father is evenly divided. However, children only receive one type of [mitochondrial DNA] from their mothers, while the fathers' mitochondrial DNA is naturally removed from the embryos. Peter Sutovsky, a professor of reproductive physiology at Mizzou and lead author Won-Hee Song, a doctoral candidate in the Mizzou College of Agriculture, Food and Natural Resources, have found a way to prevent this paternal mitochondrial DNA removal process in pig embryos, thus creating embryos with "heteroplasmy."
"As many as 4,000 children are born in the U.S. every year with some form of mitochondrial disease, which can include poor growth, loss of muscle coordination, learning disabilities and heart disease," Sutovsky said. "Some scientists believe some of these diseases may be caused by heteroplasmy, or cells possessing both maternal and paternal mitochondrial DNA. We have succeeded in creating this condition of heteroplasmy within pig embryos, which will allow scientists to further study whether paternal heteroplasmy could cause mitochondrial diseases in humans."
Autophagy and ubiquitin–proteasome system contribute to sperm mitophagy after mammalian fertilization (DOI: 10.1073/pnas.1605844113) (DX)
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Project to Repair Mitochondria Funded
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It could soon be possible to create a baby from three people, if it is made legal.
The technique, using eggs from two women and one man's sperm, would be used to prevent deadly mitochondrial diseases. The UK fertility regulator said there was no evidence that it would be unsafe, but called for extra checks. Changes to fertility regulations are being considered by government.
The illnesses are caused by damage to the tiny power stations in every cell of the body called mitochondria. One in every 6,500 babies are born with severe mitochondrial disease which means they have insufficient energy to function it leads to muscle weakness, blindness, heart failure and even death.
Mitochondria are the organelles ("small organs") within almost all biological cells that provide energy to the cell (in the form of ATP) but they also have a number of other crucial functions and biological importance in relation to diseases and death.
The SENS Research Foundation (SRF) (Wikipedia link) co-founded by Aubrey de Grey (who also co-founded the Methuselah Foundation (Wikipedia link)) are ultimately looking for ways to defeat death, or less controversially stated "ending aging" or even less so "transform the way the world researches and treats age-related disease" and identified mitochondrial mutations as one of seven key types of cellular damage they wished to find strategies and cures against.
As part of this the SRF launched a crowdfunding campaign called the MitoSENS Mitochondrial Repair Project which has now surpassed its funding target. The aim of the project is to engineer replacements for mitochondrial genes from copies of the genome so that mitochondrial functions can restored when lost as happens during aging and mitochondrial diseases.
An excerpt from the MitoSENS funding page:
At the SENS Research Foundation, we are in the early stages of creating an innovative system to repair these mitochondrial mutations. If this project is successful we will have demonstrated, for the first time, a mechanism that can provide your cells with a modified backup copy of the entire mitochondrial genome. This genome would then reside within the protective confines of the cell's nucleus, thereby mitigating damage to the mitochondrial genome. In fact, during the long course of evolution, this gradual transfer of genetic information into the nucleus has already occurred with the majority of mitochondrial genome, leaving behind a mere 13 protein coding genes within the mitochondria. Demonstrating the effectiveness of this technology would be a major milestone in the prevention and reversal of aging in the human body.
A National Academy of Medicine (formerly known as the Institute of Medicine) committee has given conditional backing to the use of mitochondrial replacement techniques (MRT). Three-person in vitro fertilisation was approved and legalized in the United Kingdom last year, but has been banned by the U.S. Food and Drug Administration since 2001, despite having been used to conceive a patient back in 2000. Mitochondrial replacement is intended to allow a couple to conceive a child, but with healthy mitochondria inserted into the embryo from a female donor:
Would it be ethical for scientists to try to create babies that have genetic material from three different people? An influential panel of experts has concluded the answer could be yes. The 12-member panel, assembled by the National Academies of Sciences, Engineering and Medicine, released a 164-page report Wednesday outlining a plan for how scientists could ethically pursue the controversial research. "The committee concludes that it is ethically permissible" to conduct such experiments, the report says, but then goes on to detail a long list of conditions that would have to be met first.
For example, scientists would have to perform extensive preliminary research in the laboratory and with animals to try make sure it is safe. And then researchers should initially try to make only male babies, because they would be incapable of passing their unusual amalgamation of DNA on to future generations. "Minimizing risk to future children should be of highest priority," the committee writes.
The report was requested by the Food and Drug Administration in response to applications by two groups of scientists in New York and Oregon to conduct the experiments. Their goal is to help women have healthy babies even though they come from families plagued by [mitochondrial] genetic disorders.
The PDF of the report, "Mitochondrial Replacement Techniques: Ethical, Social, and Policy Considerations" (DOI: 10.17226/21871) is 8.1 MB and can be downloaded "as guest" with no email confirmation.
A study by Newcastle University researchers has found that three-person in vitro fertilization is safe (does not adversely affect embryos) and can be routinely performed. Three-person IVF allows the transfer of donor mitochondria into an embryo in order to prevent mitochondrial disease:
Published today in the journal Nature, scientists at the Wellcome Trust Centre for Mitochondrial Disease at Newcastle University report the first in-depth analysis of human embryos created using a new technique designed to reduce the risk of mothers passing on mitochondrial disease to their children, which is debilitating and often life-limiting.
[...] Today researchers, in a study involving over 500 eggs from 64 donor women, publish results that indicate that the new procedure does not adversely affect human development and will greatly reduce the level of faulty mitochondria in the embryo. Their results suggest that the technique will lead to normal pregnancies whilst also reducing the risk of babies having mitochondrial disease. The results of this study will be considered by the Human Fertilisation and Embryology Authority's (HFEA) Expert Scientific Panel. The HFEA will ultimately decide whether to issue the first licence to a clinic. A licensed clinic would allow couples affected by mitochondrial disease to have the choice of whether to use pronuclear transfer to try and have healthy children.
Also at the BBC. You can fill out this form to donate eggs or sperm to the Newcastle Fertility Centre at Life.
Towards clinical application of pronuclear transfer to prevent mitochondrial DNA disease (DOI: 10.1038/nature18303)
Previously: UK Approves Three-Person IVF Babies
U.S. Panel Gives Tentative Endorsement to Three-Person IVF
(Score: -1, Offtopic) by Anonymous Coward on Friday August 26 2016, @03:18AM
By saying they need some muscle over here to get them to leave?
(Score: -1, Troll) by Anonymous Coward on Friday August 26 2016, @03:25AM
^ Pounds pug poon.
(Score: -1, Flamebait) by Anonymous Coward on Friday August 26 2016, @03:39AM
Mother Nature removes fathers' mitochondrial DNA because males are naturally inferior. This anti-Feminist research must be destroyed immediately and researchers executed.
(Score: 0) by Anonymous Coward on Friday August 26 2016, @03:46AM
Is how the Jewish God tells proper lineage of his flock from the chattel.
:)
(Score: -1, Troll) by Anonymous Coward on Friday August 26 2016, @04:01AM
What's this, Jews elevating themselves above chattel? Hebrews who were slaves themselves now fancy themselfs the slave masters? Irony, thy name is Israel.
(Score: -1, Flamebait) by Anonymous Coward on Friday August 26 2016, @05:10AM
This is great news for Francis! At least, if we can get him to stop sitting on his balls.
(Score: 2) by frojack on Friday August 26 2016, @07:37AM
"Some scientists believe some of these diseases may be caused by heteroplasmy, or cells possessing both maternal and paternal mitochondrial DNA.
Apparently they can test for paternal mitochondrial DNA, and apparently they must have found it in a significant number of cases. Otherwise there would be no basis for the belief.
So if it occurs naturally, why is this such a big deal? Testing enough pigs would have found some naturally occurring specimens, No?
What happens if ALL the maternal mitochondria are swapped out for paternal mitochondria mitochondria?
No, you are mistaken. I've always had this sig.
(Score: 1, Flamebait) by takyon on Friday August 26 2016, @08:29AM
Umm, err... they become MRAs!
https://en.wikipedia.org/wiki/Mitochondrial_DNA#Male_inheritance [wikipedia.org]
https://en.wikipedia.org/wiki/Paternal_mtDNA_transmission [wikipedia.org]
It seems like the debate is more about the extent to which it occurs than the possible effects, although there is some mention of male-inherited mitochondria being rejected in the first link.
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(Score: 2) by Immerman on Saturday August 27 2016, @01:35AM
For starters , a "significant number" can still be a quite tiny percentage of a large population. Detecting it in disease patients also tells you next to nothing about its prevalence in the larger population.
Assuming that there is correlation between heteroplasmy and some of these diseases, being able to artificially induce it also gives you another important advantage: the ability to see if it's actually the cause, or simply another effect of some other root cause.
(Score: 2) by GreatAuntAnesthesia on Friday August 26 2016, @02:15PM
I'm imagining our descendants trying to use mitochondrial DNA to study human history ten thousand years from now, when our drowned civilisation is barely more than myth and our knowledge all but lost,
This will really fuck with their heads. Why don't we just fake up some authentic-looking Indominous Rex fossils while we're at it and bury them in the bedrock? Hell, throw in a few Godzilla bones too.
(Score: 2) by mr_mischief on Friday August 26 2016, @03:25PM
"However, children only receive one type of DNA, called mitochondrial DNA, from their mothers, while the fathers' mitochondrial DNA is naturally removed from the embryos. "
That's misworded. Children receive one type of DNA, called mitochondrial DNA, only from their mothers while the fathers' mitochondrial DNA is naturally removed from the embryos. It's not that the mothers only contribute mitochondrial DNA. It's that only mothers contribute mitochondrial DNA. That's a big difference.
(Score: 2) by takyon on Friday August 26 2016, @05:27PM
They make grammar no good. Changed.
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