Can life be created simply by injecting a non-egg cell with sperm? It seems like very basic knowledge – to create a mammal embryo the egg from the female needs to be fertilized by the sperm from the male. Well, apparently not according to scientists, led by Dr Tony Perry, from the Department of Biology & Biochemistry at the University of Bath.
For many years, we have known that some living beings, such as certain insects can reproduce asexually, in a process known as parthenogenesis. In the case of mammals, embryos produced this way have never previously been able to survive. However, the researchers have found a way of inserting cells, known as parthenogenesis, with sperm that allows them to survive in 24% of cases in mice. In comparison, about 2% of mammal embryos created by nuclear transfer cloning will survive. What this means, is that viable embryos might be able to be produced without fertilizing an egg cell with sperm in the normal way and without cloning. The implications are huge.
This is a major breakthrough for embryologists who until now had ‘thought that only an egg cell was capable of reprogramming sperm to allow embryonic development to take place’ according to Dr Tony Perry. He continued that ‘our work challenges the dogma, held since early embryologists first observed mammalian eggs around 1827 and observed fertilization 50 years later, that only an egg cell fertilized with a sperm cell can result in a live mammalian birth.’
The mice that were born from this method initially displayed different DNA patterns from normal mice, but developed healthily nonetheless. That DNA showing different epigenetic marks can lead to the same development is also something that has not previously been seen.
The research is still in early stages, but the results could have significant implications in the future. For example, it could be a lifeline for various endangered species if scientists are able to start breeding them in this way. For some species, such as the giant panda, a lifeline like this may be the only chance they have got of surviving as a species in the long-term.
There will almost certainly be implications for fertility treatment. Women whose fertility has been compromised by cancer treatment may at some point in the future, be able to use this method to have healthy babies. This new way of making embryos is without a doubt going to spark a new debate as to whether or not it would be ethical to use human parthenogenesis in this way. Until now this had not been seen as possible, as embryos produced this way were not able to survive. It may well be that the ethical considerations and political lobbying against this advancement will prove to be a bigger hurdle for scientists than any technical, scientific obstacles they face.