Martian Rocks May Preserve Ancient DNA Fragments Despite Radiation, Study Finds

DNA Survival in Extreme Martian Conditions

Scientists have made a groundbreaking discovery that fragmented DNA could potentially be extracted from Martian surface rocks despite prolonged exposure to cosmic radiation, according to a recent study published in Communications Earth & Environment. The research indicates that between 1.48% and 8.45% of DNA sequences remain taxonomically identifiable even after exposure to radiation doses equivalent to 136 million years on the Martian surface, suggesting that genetic material might persist in similar environments on Mars.

DNA Survival in Extreme Martian Conditions
Martian Environment and Organic Preservation
Experimental Findings and Radiation Resistance
Implications for Mars Exploration Missions
DNA as a Definitive Biosignature
Future Research Directions

Martian Environment and Organic Preservation

The study draws parallels between Earth’s ancient sedimentary rocks and Martian conditions, with analysts noting that Mars hosted liquid water during the same period when life first emerged on Earth approximately 3500 million years ago. The Curiosity rover’s measurements at Gale Crater reportedly detected Total Organic Carbon concentrations of 201-273 ppm in 3500-million-year-old lacustrine mudstones, indicating that organic preservation is possible in Martian environments.

Sources indicate that Mars’s current hyperarid and cold conditions, combined with the absence of plate tectonics and liquid water, create an environment where organic molecules might be better preserved than on Earth. However, the planet’s thin atmosphere and lack of global magnetic field expose surface materials to intense cosmic and solar radiation, which presents the primary challenge for biomolecule preservation., according to industry developments

Experimental Findings and Radiation Resistance

Researchers extracted and sequenced DNA from terrestrial sedimentary rocks with varying organic carbon content, yielding between 184,000 and 3.8 million nucleobases from just 0.5-gram rock samples. After exposing samples to 10.45 MGy of gamma radiation—equivalent to 136 million years on the Martian surface—scientists measured a radiolytic constant of K = 0.17 MGy⁻¹ in both microbialite and iron formation samples., according to additional coverage

The report states that despite significant fragmentation, a small but measurable percentage of DNA sequences remained identifiable, demonstrating that genetic material can persist in rocks for over 100 million years under conditions similar to those on Mars. This finding is particularly significant given that the oldest DNA recovered on Earth dates back only approximately 2 million years.

Implications for Mars Exploration Missions

These findings strengthen the scientific justification for current and planned Mars missions, including NASA/ESA’s Mars Sample Return program and China’s Tianwen-3 mission. The Perseverance rover is already collecting sealed rock cores from Jezero Crater, an ancient paleolake system that once supported environments potentially conducive to life., according to market developments

According to reports, in situ analyses by Perseverance have provided strong evidence for organic compounds associated with sulfate and carbonate minerals, suggesting mineralogical contexts favorable to preservation. When Martian samples eventually return to Earth, they will undergo analysis in biosafety-controlled laboratories to search for biosignatures while maintaining strict containment protocols.

DNA as a Definitive Biosignature

DNA represents the most definitive biomolecule for life detection since all known terrestrial cellular life forms use it to encode genetic information. The report emphasizes that no non-biological processes are known to produce DNA, making its identification as a biosignature uncontroversial. Recent analysis of samples from asteroid Bennu by NASA’s OSIRIS-REx mission has identified all nucleobases found in terrestrial DNA and RNA, supporting the possibility that DNA building blocks can form and persist in extraterrestrial environments.

While synthetic biology has expanded to include alternative genetic polymers called Xeno Nucleic Acids (XNAs), analysts suggest that DNA remains an appropriate model for investigating radiation-induced damage in potential nucleic acid-based life beyond Earth, given shared structural characteristics and degradation mechanisms.

Future Research Directions

The study examined terrestrial analogue rocks from carbonate- and iron-rich sedimentary environments similar to those being sampled by Perseverance on Mars. Researchers indicate that future Mars missions targeting past habitable environments will likely focus on similar rock types rich in silica, iron oxides, carbonates, and sulfate salts.

Scientists suggest that understanding the long-term preservation of DNA in geological substrates over multimillion-year timescales is critical for both life detection and planetary protection safety assessments. The demonstrated persistence of identifiable DNA fragments despite extensive radiation exposure provides renewed optimism for finding evidence of past life on Mars, should it have ever existed.