Researchers at the University of Namur have taken a close look at how spaceflight affects a tiny aquatic animal called the bdelloid rotifer Adineta vaga. These microscopic creatures were sent to the International Space Station (ISS) to explore how life responds to the unique conditions of space, such as microgravity and increased radiation. To do this, the team used RNA sequencing, a technique that allows scientists to see which genes are turned on or off in an organism under different conditions.

A Assembled Hardware with a transparent view illustrating the internal hardware frame and culture bag. On the top, iButton is visualized as purple ring. Photo credits: Kayser Italia B) View of the culture bag loaded inside the internal frame of hardware. Each bag contains 10,000 A. vaga individuals. Photo credits: Marc Guillaume. C ESA astronaut Luca Parmitano handling the experiment on board the ISS. Photo credits: ESA. D Operational Timeline and Procedures for the experiment. Similar timeline and temperature were achieved for space and ground samples

To grow the rotifers aboard the ISS, the researchers developed new hardware that allowed the animals to be cultured almost autonomously, meaning astronauts did not need to intervene much. After the rotifers spent time in low Earth orbit, the team analyzed changes in their gene expression. They found that nearly 19% of the rotifer’s genes responded significantly to the space environment. Many of these genes were related to critical cellular processes like protein synthesis, RNA metabolism, and DNA repair. These changes likely help the rotifers cope with the stresses of microgravity and radiation exposure.

One of the most intriguing findings was the involvement of genes that came from other organisms through a process called horizontal gene transfer. Unlike the typical inheritance of genes from parent to offspring, horizontal gene transfer allows organisms to acquire genes from unrelated species. The researchers found that these foreign genes were often among those most affected by spaceflight, suggesting they might help Adineta vaga adapt to extreme or novel environments such as space.

This research is important because it expands our understanding of how living organisms respond to space conditions beyond traditional models like mice or human cells. It also shows that Adineta vaga could serve as a valuable model for future experiments in space biology, helping scientists explore fundamental questions about life’s resilience and adaptability beyond Earth.