Monash Researchers Find Antarctic Microbes Actively Swapping Genes To Survive On Trace Gases

Microbes living in Antarctic desert soils are far from dormant. New research led by scientists at Monash University has found that bacteria in some of the continent’s harshest environments are frequently acquiring genetic material from neighbouring organisms, including distantly related species, to maintain the metabolic functions needed to survive on atmospheric trace gases.

The study, published in Nature Communications, analysed 676 metagenome-assembled genomes from 16 soil sites in the Mackay Glacier region of Antarctica’s McMurdo Dry Valleys. The researchers identified 10,942 horizontal gene transfer events involving 98.2 per cent of the genomes studied, revealing that gene sharing between microbes is widespread across Antarctic soil communities.

The findings challenge longstanding assumptions that Antarctic soil microbes are largely inactive, and provide evidence that previously unrecognised evolutionary dynamics are actively shaping how microbial communities function in one of Earth’s most extreme environments.

Swapping genes for energy

The research was led by scientists from the Securing Antarctica’s Environmental Future (SAEF) ARC Special Research Initiative, based at Monash University in Melbourne.

The central finding is that genes involved in energy production and conversion are transferred between microbes at a higher frequency than expected. This contrasts with patterns observed in more temperate environments, where energy metabolism genes are among the least frequently transferred.

Of particular interest are genes for aerotrophy, the process by which microbes consume atmospheric trace gases such as hydrogen and carbon monoxide to generate energy, fix carbon and produce metabolic water. These genes were among the most frequently shared between organisms and were also subject to intense natural selection to preserve their function.

Lead Author and SAEF PhD Candidate at Monash University, Yongyi Peng, explained: “In harsh environmental conditions, microbes tend to have smaller genomes because there is limited energy available. But they still need the essential functions required for survival. Frequent gene transfer between species can help them maintain those key biological processes.”

“Genes for aerotrophy were among the most frequently identified, and these genes were also strongly selected, helping preserve their function over time. Largely because aerotrophy is critical to microbial survival in Antarctica.”

How aerotrophy sustains life in polar deserts

Antarctic desert soils are extremely low in organic carbon, the primary energy source for microbial life in most ecosystems. Aerotrophic bacteria overcome this limitation by using high-affinity enzymes to oxidise hydrogen and carbon monoxide from the atmosphere at trace concentrations.

The research found that approximately a quarter of the carbon monoxide dehydrogenases and [NiFe]-hydrogenases identified in the study were predicted to have been horizontally acquired, and were often associated with mobile genetic elements such as insertion sequences, transposons and phage recombinases.

Previous work from the same research group has shown that bacteria capable of atmospheric chemosynthesis comprise roughly 90 per cent of microbial communities in Antarctic polar desert soils, spanning nine phyla. The new study provides a mechanism for how this capability has become so widespread: horizontal gene transfer allows the trait to spread across distantly related lineages rather than relying solely on vertical inheritance through cell division.

Strong selection preserves function

The study went beyond identifying gene transfer events to examine how natural selection acts on horizontally acquired genes.

Analysis of genetic polymorphisms across the 16 soil metagenomes revealed widespread purifying selection, where deleterious mutations are removed, across Antarctic protein-encoding genes. Aerotrophy genes showed significantly lower ratios of nonsynonymous to synonymous mutations compared to genome-wide averages, indicating that natural selection is acting to conserve their function.

The researchers used predicted protein structures to examine where mutations were tolerated within hydrogenase enzymes. Nonsynonymous changes, which alter the amino acid sequence, were concentrated in surface-exposed and structurally flexible regions of the proteins. Buried sites and those near the catalytic active centre were highly conserved, with mutation rates at active-site cysteine residues markedly lower than the overall average.

These patterns were confirmed in an independent dataset of nine Antarctic metagenomes from geographically distinct regions across East Antarctica, including Dronning Maud Land, Robinson Ridge and Bunger Hills.

Co-occurrence drives gene sharing

The study also examined ecological factors influencing which organisms exchange genetic material. The researchers found a positive correlation between microbial co-occurrence, meaning species that tend to be found together, and the frequency of gene transfer between them.

Closely related species exchanged genes more frequently, with within-phylum transfers occurring more often than between-phylum transfers. However, several cross-phylum transfer events were also identified, including notable gene flow between Desulfobacterota_B and Acidobacteriota.

The dominant phylum, Actinomycetota, accounted for more than half of all inferred horizontal gene transfer events, consistent with its prevalence across Antarctic soil communities.

Implications for climate adaptation

Co-Author and SAEF Researcher, Ry Holland, noted that horizontal gene transfer combined with natural selection provides a framework for understanding how microorganisms diversify and adapt in natural environments.

“This study is a big piece of the puzzle helping us understand how these dynamics shape metabolic traits in Antarctic soil microbes, which experience extremes of temperature, aridity, light, UV, salinity and nutrients,” Dr Holland remarked.

“We hypothesize that these eco-evolutionary dynamics are of particular importance in Antarctica to overcome slow growth and turnover that would otherwise result in slow rates of adaptation.”

The authors suggest the findings may also offer insight into how Antarctic microbial communities will respond to climate change. Because horizontal gene transfer enables rapid genetic diversification independent of cell division rates, these communities may already be equipped to adapt to shifting environmental conditions, though whether that increases their resilience or vulnerability remains an open question.

The research was supported by ARC SRIEAS Grant SR200100005 and contributes to the Australian Antarctic Science Decadal Strategy. The study’s data and analysis code are publicly available through NCBI BioProject PRJNA630822 and GitHub.

Last Updated on September 6, 2026 by Nick Ross