Scientists have successfully genetically engineered invasive female fruit flies to reproduce without the need for males.
The researchers disclosed on Friday that they induced a “virgin birth” or parthenogenesis, in the Drosophila melanogaster (fruit fly) species, marking the first-ever occurrence of such a phenomenon in a traditionally sexually reproducing animal.
The offspring produced from these virgin births were able to further propagate without the need for mating. The comprehensive study was recently published in the journal Current Biology.
Facultative parthenogenesis is a cool trick some organisms have where they can switch between making babies the usual way, with a partner, and making babies all by themselves (which is called asexual parthenogenesis).
Researchers looked at two types of fruit fly species. One type needs a male to have babies (sexual reproduction), while the other type can have babies without a male (parthenogenesis). They studied the genetic makeup of these two types and found differences in how certain genes work in their eggs.
These researchers then wondered if they could make a related fruit fly species, which normally requires a male to reproduce, have babies without a male. They did this by tweaking some of the genes they found in the first type of fruit fly.
They focused on three specific genes: one called ‘polo’, another called ‘Desat2’, and a third one named ‘Myc’. By making ‘polo’ work harder and ‘Desat2’ work less, they managed to make the fruit fly that normally needs a male to have babies reproduce without one. And this effect was even stronger when ‘Myc’ was made to work harder.
According to the researchers, the eggs produced by these genetically modified flies were able to start developing into baby flies on their own. They managed to do this by creating their own center for cell division (centrosome), combining the cell division products, and starting to develop. These baby flies ended up having an extra set of chromosomes, making them triploid.
According to Barron’s, parthenogenesis, while rare, is not entirely alien to the animal kingdom. Certain species of lizards and birds, which reproduce by laying eggs, can bear offspring without the necessity for mating. Usually, this occurs later in life when males are unavailable. However, the ability to trigger such a process in a species that traditionally reproduces sexually is a first.
The outlet added that just last month, a female crocodile in a Costa Rican zoo that had no prior contact with a male surprised the world by laying an egg that carried a fully developed fetus. This was the first recorded instance of a virgin birth in reptiles.
While the science community celebrates the remarkable accomplishment, the ethical repercussions of this research have come into sharp focus.
Firstly, concerns have been raised about biodiversity and ecosystem balance. Parthenogenesis, the scientific term for virgin birth, typically occurs in nature when no males are available. This genetic engineering could disrupt the balance of sexes in certain populations if it became commonplace, with unforeseen impacts on ecosystems.
Additionally, critics argue that scientists are ‘playing God’ by interfering with the natural reproductive processes of animals.