Scientists have grown microscopic algae aboard the International Space Station to investigate how spaceflight affects their genetic stability. Space Algae-1 grew ultraviolet light-mutagenised Chlamydomonas reinhardtii in the ISS VEGGIE plant growth chamber for approximately 40 mitotic generations over one month. Whole-genome sequencing of pooled cell samples collected every 10 generations found that the spaceflight cultures had an approximately 50% increase in DNA polymorphisms compared with ground controls. According to Nasa, a novel base substitution signature among the mutations. The findings are part of research into whether microalgae could support biological life-support systems during long-duration and deep-space missions.
Why did algae grown on the ISS show about 50% more DNA changes
Whole-genome sequencing was carried out on pooled cell samples collected every 10 generations. The sequencing showed that the cultures grown in spaceflight had an approximately 50% increase in DNA polymorphisms compared with ground controls. The results therefore identified a difference in the genomic changes observed between the cultures grown aboard the ISS and those maintained in ground-based controls.The mutations identified in the spaceflight cultures also had what Nasa describes as a “novel base substitution signature”. According to the agency, suggested a risk that microalgae may be unstable for long-term production in space. The Space Algae research is therefore examining genomic stability in organisms that could have applications in biological life-support systems during space missions.
Why is Nasa studying algae for long-duration space missions
Nasa’s Space Algae programme is based on the potential use of plants and microbes for biological support during crewed space missions. The agency’s Space Algae research specifically focuses on photosynthetic organisms and how their genetic stability could be affected by the conditions of spaceflight. Understanding these effects is described by Nasa as essential for supporting productivity during long-duration and deep-space missions.The experiments are also connected to Nasa’s wider synthetic biology research, which aims to engineer biological systems that can provide resources for space exploration, including food, life support and materials. Nasa identifies Space Algae as one of its current efforts within its Synthetic Biology Group, alongside programmes including BioNutrients and carbon-dioxide-based manufacturing.
What is Nasa studying in its Space Algae-2 experiment
Nasa’s subsequent Space Algae-2 experiment focuses on Arthrospira platensis, an edible cyanobacterium commonly known as Spirulina. The experiment seeks to grow serial cultures so that researchers can study how the organism evolves during long-term spaceflight. This work follows the Space Algae-1 investigation into genomic changes in microalgae grown aboard the ISS.Biological responses in the Space Algae-2 cells will be assessed through multi-omics analyses. These analyses will examine mutation load, gene and protein expression, metabolic and nutritional composition, and cell morphology. The Space Algae experiments on the ISS investigate how spaceflight affects microalgae’s genomic stability, while ongoing research is focused on the long-term adaptation of Spirulina.
