A paper published in Nature Communications showed that mouse sperm injected with modified inactivated embryos can produce healthy offspring. The results showed that sperm can mature without eggs, which was previously thought to occur only in eggs. This motivates researchers to explore how this developmental process occurs. The fertilization process involves multiple steps in the transformation of sperm and eggs into embryos.
During the process of fertilization, a process called reprogramming takes place many chromosomal and DNA changes. These changes make the sperm mature and divide to produce differentiated cells in the body. This ability is called pluripotency. However, the general view is that sperm can only be reprogrammed in eggs to achieve pluripotency. Anthony Perry and his colleagues injected sperm cell nuclei into chemically engineered mouse embryos and then allowed them to divide into two cells for the first time. These embryos are chemically treated to contain only a set of unpaired chromosomes, not the paired chromosomes that are usually produced by the fusion of sperm and egg. The resulting embryos grow into healthy individuals (although the highest percentage is only 24% of the control group).
The author has not shown how to reprogram the sperm genome, but found that the modified embryo and the control group have certain chromosomal and DNA similarities, but there are also differences in the ability to perform cell operations, which means that the two have been reprogrammed. The programming path is different.
The above results show that in some cases, the sperm maturation process of the egg can be bypassed, but this discovery is too early for human applications. The viability of injected embryos is very low. In addition, this study was conducted in mouse embryos, and there is no evidence that human embryos can be successful.