Extreme environments leave genomic imprint in tiny organisms: Study

Illustration of Pyrococcus furiosus, an extremophile first discovered thriving at 100 C near a volcanic vent in Italy. (Michelle Kropf image) DNA of extremophiles living in comparably harsh conditions are similar despite being biologically unrelated The signature written in genomic DNA has long been linked to ancestry, not to geographic location. But a recent study using AI from Western University, published in the high impact journal Scientific Reports , provides evidence that living in extreme temperature environments leaves a discernible imprint on the genomes of microbial extremophiles. Using machine learning, an interdisciplinary research team co-led by Western biology associate professor Kathleen Hill and computer science adjunct professor Lila Kari found that, unexpectedly, the genomic signatures of microbial extremophiles living in comparable extreme environments are similar, even though they belong to two different domains of the Tree of Life, namely Bacteria and Archaea. Kathleen Hill (Rachel Keyes photo) "This discovery flies in the face of conventional thinking that pervasive, genome-wide, genomic signatures carry only information about naming, describing and classification of organisms," said Hill, an expert in gene mutation, population genetics and genome evolution. Extremophiles live in exceedingly harsh environments like volcanoes, deep-sea trenches and polar regions, all characterized by extreme conditions (high temperature, radiation, pressure or acidity), that would pose an existential threat to most other living organisms.