The stem cell technique used by the researchers is not entirely new, but all previous attempts faced seemingly insurmountable problems.
However, by editing 20 different genes in the mice’s stem cells, the researchers were able to prevent these issues.
Co-author of the study Dr Wei Li says: ‘This work will help to address a number of limitations in stem cell and regenerative medicine research.’
Since the technique requires editing the genome of the parent’s stem cells, it is also prohibited in humans.
The International Society for Stem Cell Research’s ethical guidelines for stem cell research do not allow heritable genome editing for reproductive purposes nor the use of human stem cell-derived gametes for reproduction because they are deemed as currently unsafe.
The first mouse with two biological fathers has survived until adulthood, a new study has revealed.
Researchers from the Chinese Academy of Sciences say they have succeeded in breeding mice using only genetic material from two males.
Through a technique called ’embryonic stem cell engineering’, scientists created eggs from the sperm of one father which could be fertilised by the other.
The researchers’ stem cell technique is not a novel one, but all earlier attempts encountered seemingly intractable issues.
When mice were bred with two sets of male genes, they either didn’t grow at all or had serious developmental defects that kept them from growing up to adulthood.
Researchers were able to avoid these problems, though, by altering 20 distinct genes in the mice’s stem cells.
Dr. Wei Li, a co-author of the study, states: “This work will help to address a number of limitations in stem cell and regenerative medicine research.”. “…
This significant discovery could open the door for gay men to have children who are biologically related to both fathers, even though it is currently only feasible in mice.
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The researchers first had to change the male sex cells from one parent into female sex cells in order to produce children with two biological fathers.
By injecting mouse sperm into an oocyte—an immature egg cell that has had its genetic material removed through a process known as enucleation—the researchers were able to create a new cell.
Because of this, a stem cell—a type of cell that can develop into any other kind of cell in the body—was produced that only contained male DNA from the first parent.
One of these stem cells and a sperm cell from a different male were then injected into another enucleated immature egg by the researchers.
By combining the DNA of both parents, these male cells produced an embryonic stem cell that was used to create an embryo that could be implanted in a surrogate mother.
Only the genetic material from the two males was present in the offspring that the mother gave birth to after the embryo had fully developed.
The technique has been used to produce viable embryos, and scientists have long known that this is possible.
On the other hand, no one has ever succeeded in producing “bi-paternal” mice that can truly live to adulthood.
The sperm’s genetic material from a male and the ovum’s (egg) genetic material from a female combine during heterosexual reproduction.
This is known as “crossing over,” and it occurs when a set of genes from the mother, known as “homologous chromosomes,” join forces with those from the father.
“Imprinting abnormalities” result from improper gene copying when both sets of homologous chromosomes originate from either two males or two females.
Developmental defects brought on by these anomalies may keep the children from leading healthy lives.
Because of imprinting genes’ special properties, scientists think that they are a major obstacle to unisexual reproduction in mammals, according to co-author Dr. Qi Zhou.
These genes cause bi-maternal or bi-paternal embryos to develop improperly and stall at some stage of development, even when they are created artificially. “.”.
To avoid imprinting abnormalities, the researchers in this study altered the mice’s DNA using a gene editing technique known as CRISPR.
Following the creation of stem cells from the sperm of the first male, they added or deleted genetic code segments that regulate imprinting at 20 different locations in the mice’s DNA.
These genetically altered stem cells had a far higher chance of developing normally when mixed with another male’s sperm.
As a result of these modifications, mice with two fathers were able to survive to adulthood for the first time.
These findings offer compelling evidence that imprinting abnormalities are the primary obstacle to mammalian unisexual reproduction, according to study co-author Dr. Guan-Zheng Luo of Sun Yat-sen University in Guangzhou.
This strategy has the potential to greatly enhance the developmental results of cloned animals and embryonic stem cells, opening up a promising avenue for the development of regenerative medicine. “.”.
The authors do admit that these results have some important limitations.
Not every pup that was born survived to adulthood, and only 11.8 percent of the viable embryos were able to develop to birth.
The adult-surviving mice were sterile, had stunted growth, and had shorter lifespans.
Nonetheless, these findings represent the first encouraging attempts to allow gay men to have children with both fathers.
Theoretically, a similar method might be used to produce an embryo from sperm from one human partner and stem cells from the other.
The child would have only genetic material from both fathers, but still require a female surrogate to carry them to term.
The researchers currently intend to test this strategy on larger animals, such as monkeys, but caution that the technological challenges will be much greater.
This implies that it might take years of work to get the method to work in people.
Even though it is feasible, not everyone agrees that researchers should attempt to develop this technology in people.
As psychologists refer to it, “I do understand that some might have a strong desire to have biological children because it offers some virtual immortality,” Lukasz Konieczka, executive director of the LGBT+ charity Mosaic Trust, told MailOnline.
I don’t believe that investing time and money in this kind of technology is necessary because there are still children in the world today who are in the foster system because their biological parents were abusive or neglectful. “…
In humans, the method is also forbidden because it involves altering the parent stem cells’ genome.
Heritable genome editing for reproductive purposes and the use of human stem cell-derived gametes for reproduction are prohibited by the International Society for Stem Cell Research’s ethical guidelines for stem cell research because they are currently considered unsafe.