In a major breakthrough in the field of epigenetics, scientists at the Chinese Academy of Sciences may have just rendered males obsolete... well, for mice anyway.
According to a study published Thursday in the journal Cell Stem Cell, a team of researchers from the Chinese Academy of Sciences (CAS) used stem cells and gene editing to produce over two dozen healthy mice from female parents.
The newborn mice were healthy and able to go and have pups of their own.
Some reptiles, amphibians and fish can reproduce with one parent but it is challenging for mammals to do the same even with the help of fertilization technology.
The procedure generated 210 embryos, of which 29 survived to be born as healthy, normally developed mouse pups.
Stem cells are widely used for genetic studies because they have the potential to develop into any other type of cell.
Genomic imprinting simply refers to the suppression of selected genes, from either the mother or the father, during the development of the germ cells (sperm and egg cells) that pass on genetic information during reproduction.
In mammals, certain maternal or paternal genes are shut off during germline development by a mechanism called genomic imprinting, so that offsprings that don't receive genetic material from both a mother and a father might experience developmental abnormalities or might not be viable. According to Li Wei, another co-senior author, the defective mice were smaller than normal, or demonstrated poor motor skills.
Specifically, the scientists produced normal mice from same-sex parents using haploid embryonic stem cells with gene deletions. This created an embryo containing only genomic DNA from the two male parents.
"In order for same-sex parents to both have genetic contributions to their children in an assisted reproduction setting, it is likely another technological leap will be required".
In the case of the female mice, three "imprinting regions" were deleted from the stem cells, which were then injected into the eggs of another mouse.
Mice pups from two dads were also born using a similar but more complex approach, but they only survived for a couple of days. Of the 12 born, just two survived for more than 48 hours, but the technology is far from ready for the leap to humans, the scientists noted.
Despite having success with mice, Li said the same technique can not easily be applied to other mammals - such as humans - since each species has a unique set of problematic imprinted genes, and identifying these takes time. But by blurring the boundaries between egg and sperm with genetic adjustment, scientists are now helping us break the rules of mammalian reproduction.
However, experts have been quick to warn that use of the technique on human is extremely unlikely.
"If the research is reproducible, and also works in humans, it still has to be shown to be safe,"Bob Williamson, the chair of the Board of Stem Cells Australia, said". (Empty or not, an eggy enclosure is still necessary to bring sperm and sperm together.) These odd hybrid embryos-literal egg shells containing double doses of paternal DNA-were then transferred into a surrogate mouse mother.