Parthenogenotes are egg cells that have been “tricked” into becoming an embryo without actually being ferti,

lized by sperm. Parthenogenotes die after only a few days.

Researchers previously thought parthenogenotes were not viable vehicles for life. But as part of the latest research effort, scientists injected the parthenogenotes with mouse sperm. The non-traditional embryos produced mice offspring 24 percent of the time.

“This is first time that full term development has been achieved by injecting sperm into embryos,” Tony Perry, a researcher at the University of Bath, said in a news release. “It had been thought that only an egg cell was capable of reprogramming sperm to allow embryonic development to take place.”

The newborn mice are all healthy and were able to produce an additional two generations of mice.

However, their DNA development was marked by different epigenetic signatures than those observed during traditional fertilization. The findings, detailed in the journal Nature Communications, suggest successful mammalian birth can be achieved via at least two different epigenetic pathways.

“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,” added Perry.