In a groundbreaking study published in Current Biology, scientists have successfully genetically engineered female fruit flies to reproduce without mating, marking the first time parthenogenesis, or “virgin reproduction,” has been induced in insects. This discovery has important implications for our understanding of reproductive biology and may shed light on the possibility of virgin birth in other species.
Hymenopteran reproduction, or parthenogenesis, is a rare phenomenon in the animal kingdom. Although some egg-laying animals, such as lizards and birds, are able to give birth without mating, it usually occurs later in life when males are absent. Last month, scientists reported the first recorded case of a “virgin birth” in a female crocodile at a zoo in Costa Rica, further emphasizing the prevalence of the phenomenon.
The study’s lead author Alexis Sperling, a researcher at the University of Cambridge, and her team set out to identify the genetic cause of “virgin birth” by studying fruit flies (Drosophila melanogaster). Fruit flies are widely used in genetic research because of their well-studied genomes and extensive knowledge base.
The researchers sequenced the genomes of two strains of another fruit fly species, Drosophila mercatorum. One of them reproduces exclusively by virgin reproduction, while the other requires a male. By comparing the results, the scientists sought to identify the genes responsible for virgin reproduction.
Using genetic manipulation techniques, they altered the genes of Drosophila melanogaster to match the genes observed in its close relative. This resulted in fully parthenogenetic flies that exhibited virgin births.
More than 220,000 fruit flies participated in the study, which lasted six years. When the genetically engineered flies were isolated from males, about 1-2% of them gave up on finding a mate about halfway through their life cycle (about 40 days) and gave birth to a virgin. The offspring of these flies – all females – also reproduced at the same rate.
Sperling emphasized the significance of this achievement, stating that it would be virtually impossible to replicate in any other animal because of the large amount of data available on fruit flies. Although mammals, including humans, are not capable of virgin birth due to the specific genes required for sperm, Sperling believes that more species than currently known may be capable of this phenomenon.
According to Sperling, “We can speculate that it happens later in life because they’ve given up on finding a mate – and then they just put themselves out there.” This suggests that virgin births may be a “last-ditch effort” to ensure the survival of the species, although further research is needed to confirm this theory.
