33 groups of virus genera, 28 of which are not known to modern science have been identified by scientists in 15,000-year-old ice cores samples extracted from a Tibetan glacier.
In 1992, a team of researchers collected samples of ice cores from a glacier on the Tibetan plateau; They calculated that the ice was approximately 15,000 years old. The ice was collected from the Guliya ice cap (northwestern Tibetan Plateau, China).
Some of the samples were stored in a frozen state for later study.
Then, in 2015, another team collected samples of ice cores from the same glacier; They were also stored for later study.
Then, researchers at the Ohio State University and the Lawrence Berkeley National Laboratory conducted a portion of the planned tests for the nuclei, observing what kind of organisms could get trapped in them.
When the 1992 and 2015 teams originally collected their ice core samples, they did not make sure that the equipment they were using would not contaminate the cores they were collecting.
That meant that the researchers of the new study had to take special care to eliminate any contamination that had occurred during the initial extraction and ensure that they did not introduce any contaminants themselves.
In order to ensure having a pristine sample, the researchers, working in a cold storage facility, first cut part of the outer layer of each core sample.
Then, each sample was washed with ethanol to melt approximately half an inch of ice.
Each was washed again with sterile water to melt the same.
The team also created test samples by repeating the same cleaning procedure in the ice cores that had first been covered with known viruses and bacteria.
The samples that remained were considered pristine and ready for study.
A close look at the newly cleaned ice cores revealed the presence of 33 groups of virus genera, 28 of which are not known to modern science.
“viral particle enrichment and ultra-low-input quantitative viral metagenomic sequencing from ∼520 and ∼15,000 years old ice revealed 33 viral populations (i.e., species-level designations) that represented four known genera and likely 28 novel viral genera (assessed by gene-sharing networks),” the researchers wrote in the study.
The researchers, who publish results on bioRxiv, noted that the viruses they found in the nuclei of the two sites differed from each other, probably because they represented different points in time and, therefore, differences in climate.
They point out that their work could increase in importance as the planet warms due to global warming and melts glaciers, possibly reactivating deadly viruses, scary scenario mankind will face if we don’t control rapid temperature rises.