In a move that is casting some serious doubt on assumptions about reproduction that have been held for centuries, scientists have just managed to breed mice without the need for fertilized eggs.
The team of embryologists at the UK’s University of Bath injected sperm into embryos and successfully spurred full-term development. One of the researchers, Tony Perry, told the Telegraph: “Our work challenges that dogma, held since early embryologists first observed mammalian eggs in around 1827 and observed fertilisation 50 years later, that only an egg cell fertilised with a sperm cell can result in a live mammalian birth.”
This means that a fertilized egg might not actually be the only thing that can divide and bring about life after all, and it also indicates that an egg cell is not the only type of cell that can reprogram sperm to spur embryonic development. This opens up the possibility of using other types of cells to accomplish this feat.
Until now, it was believed that a female egg was the only thing that could incite the changes in sperm needed to create a baby, because eggs form a specific type of cell division wherein only half of the number of chromosomes get carried over. Sperm cells also form in this way, so when an egg and sperm meet, they are able to form the full genetic quota; half of the DNA comes from the mother and the other half from the father.
The researchers took unfertilized eggs from female mice and managed to coax them into becoming a sort of “pseudo-embryo” called a parthenogenote, and the experiment reported a success rate of 24 percent. All of the resultant pups seem to be perfectly healthy, and some of them have gone on to have pups of their own in the traditional way. These subsequent generations also noted similar life expectancies.
This success rate compares quite favorably to the 1 to 2 percent success rate noted using the controversial cloning method of transferring DNA to donated eggs made famous by Dolly the Sheep.
Speaking to the Guardian, Perry said: “What we’re talking about are different ways of making embryos. Imagine that you could take skin cells and make embryos from them? This would have all kinds of utility.”
How could this fertilization method be used?
This technique could allow for a number of possibilities. For example, gay couples would be able to create a child who has the DNA of one half of each of them, although they would still need the services of a woman to actually carry the baby.
Women who face fertility issues as a result of radiotherapy would still be able to have their own children, as would women who are older and experiencing a decline in egg quality. It is also believed that the technique could help preserve endangered species. When non-egg cells are used there won’t be any need to recover eggs, so this could help keep certain species in existence longer.
There’s even a chance that a man could have his own child with his own sperm and cells, and the child would be akin to a non-identical twin, although it’s hard to imagine why anyone would ever feel compelled to do such a thing.
Mother Nature doesn’t usually take kindly to interference
Of course, any time you interfere with nature, all sorts of things could go wrong. One need only take the example of genetically modified crops and the host of problems they are causing to the health of humans and animals as well as the environment at large. This process could also ultimately open up some ethical and legal concerns depending on just how far the scientists are able to take it, how it is tested, and how it is actually used.