How radiation resistant bacteria share secrets with a tough cousin
A comparative genomic study reveals that the hardy microbe Deinococcus radiodurans is most closely related to Deinococcus wulumuqiensis, holding shared tools for survival across chromosomes and an extra DNA ring.
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The full story with proper science words explained.
A tough survival kit
Picture taking huge bursts of radiation, running out of food, and taking in toxic metals, yet staying alive. That is normal for Deinococcus radiodurans, one of the most famous radiation resistant bacteria known today.
A team set out to find its closest living kin and inspect its inner defence tools. First, they pulled out 16S rRNA. This is a common RNA code used to place single-celled life on family trees.
Next, the team built a tree using the maximum likelihood method. This is a maths tool that finds the tree shape most likely to produce the observed code. The tree linked test strain DSM 20539T directly to a partner, Deinococcus wulumuqiensis R12T.
Matching blueprints
To test this bond, the team ran an OrthoANI test. This computer check measures genome match by comparing shared DNA letters between two strains. It works like lining up two books to count identical lines.
The two strains scored about 85.6% similarity. This was higher than any other bug tested, confirming that the two are very close kin.
The team also mapped where the bug stores its survival gear. Codes that help it endure starvation, cell stress, and broken DNA sit across its main chromosomes and a megaplasmid. A megaplasmid is a large extra ring of DNA that holds helpful genes.
Through reannotation—updating and re-analysing gene maps with modern tools—the team identified new genes that encode heavy metal defence proteins.
Why it matters
Broad genomic studies on this exact strain are rare. Pinpointing its closest relative helps us see how extreme microbes adapt to harsh stress, mend broken DNA, and handle toxic metals.
Unanswered questions
The study text reports slightly conflicting OrthoANI scores, listing both 85.60% and 85.56%. Specific lab tests verifying the identified heavy metal defence proteins are not detailed in the paper.
Science words
- 16S rRNA
- A standard RNA gene component used in microbiology to determine evolutionary relationships among bacteria.
- Maximum likelihood method
- A statistical approach used to build evolutionary trees by identifying the tree structure most likely to produce the observed genetic data.
- OrthoANI
- An in-silico genomic metric used to measure overall sequence similarity between two bacterial genomes.
- Megaplasmid
- A very large, circular extra-chromosomal DNA molecule found in bacteria that carries non-essential but beneficial genes.
- Reannotation
- The process of updating and re-analysing the functional descriptions and locations of genes in a previously sequenced genome.
Check it yourself
This story is based on a real research paper in Scientific Publication by Hailu, Mohammed. We write with AI help and check it against the paper, but the original is the final word.