In the news

In a recent milestone, researchers from Cambridge University and the California Institute of Technology achieved a remarkable feat: transforming a sexually reproducing fruit-fly species into one capable of asexual reproduction through minor genetic modifications.

About Drosophila

Drosophila is a genus of two-winged flies commonly known as fruit flies that are used in evolutionary and developmental studies.
It is a genus of flies, belonging to the family Drosophilidae, whose members are often called “small fruit flies” or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit.
The Drosophila melanogaster genome has 200,000,000 base pairs distributed across four DNA molecules, encoding about 13,600 genes.
Hence it is one of the most widely-used and preferred model organisms in biological research across the world for the last 100 years.

Parthenogenesis Discovery: Parthenogenesis, or fatherless reproduction, was observed in Drosophila mangebeirai, a species consisting solely of females.
Facultatively Parthenogenetic Species: Approximately 76% of sexually reproducing species, including Drosophila mercatorum, were found to exhibit facultative parthenogenesis, wherein isolated virgin females hatch eggs that develop into offspring without fertilization by males.
Canonical Species: Drosophila melanogaster, the standard species for research, strictly reproduces sexually.

Identifying Relevant Genes: Researchers aimed to identify genes facilitating parthenogenetic development in Drosophila mercatorum eggs and modify the Drosophila melanogaster genome accordingly.
RNA Sequencing: Utilizing RNA sequencing, researchers identified 44 genes in parthenogenetic D. mercatorum eggs that exhibited differential expression compared to sexually reproducing eggs.

Genetic Modifications: Researchers manipulated the expression levels of specific genes in the Drosophila melanogaster genome to mimic those observed in parthenogenetic D. mercatorum eggs.
Outcome: Genetic alterations, including overexpression of the pologene and Myc gene and reduced expression of the Desat2 gene, resulted in approximately 1.4% of D. melanogaster eggs exhibiting parthenogenesis, with viable offspring reaching adulthood.
Reproductive Potential: Parthenogenetically produced adult flies were capable of mating with males and producing progeny, demonstrating facultative parthenogenesis in a strictly sexually reproducing species.

Role of Polar Bodies: Polar bodies, by-products of chromosome transmission mechanisms during fertilization, were implicated in initiating embryonic development in unfertilized eggs.
Efficiency Alterations: Genetic modifications likely impaired the sequestration and disposal of polar bodies, enabling them to substitute for the missing male pronucleus and initiate embryonic development.

Pest Management: Raises concerns about unintended consequences in pest control strategies reliant on sterilization or genome editing.
Genetic Engineering: Opens avenues for genetic manipulation in model organisms, aiding research in gene drive technology and population control.
Conservation Biology: Offers insights into species adaptability and potential impacts of genetic interventions on natural populations.