A research team led by András Simon at Karolinska Institutet have managed to sequence the giant genome of a salamander, containing six times more DNA than the human genome. The project was enabled by sequencing at the SciLifeLab National Genomics Infrastructure (NGI) and SciLifeLab Bioinformatics services. Amongst the early findings is a family of genes that can provide clues to the unique ability of salamanders to rebuild complex tissue, even body parts. The study is published in Nature Communications.
The sequencing of the Iberian ribbed newt salamander is the first time that an entire newt genome has been sequenced, an achievement that can give rise to new discoveries on the amphibian’s ability to recreate brain neurons as well as entire body parts. Amongst the first findings are a multitude of copies of a certain microRNA group, which in mammals is mainly found in embryonic stem cells, but also in tumour cells. Even though the abundance of stem cell microRNA genes is quite surprising, it alone cannot explain how salamanders regenerate so well. András Simon predicts that the explanation lies in a combination of genes unique to salamanders and how other more common genes orchestrate and control the actual regeneration process.
One of the reasons why salamander genomes have not been sequenced before is its sheer size – six times bigger than the human genome in the case of the Iberian newt, which has posed an enormous technical and methodological challenge.
“It’s only now that the technology is available to handle such a large genome,” says Professor Simon. “The sequencing per se doesn’t take that long – it’s recreating the genome from the sequences that’s so time consuming.”
Read the full paper in Nature communications