Virus resurrected from 700-year-old caribou dung

Written by: Lisa Stelzner

Primary Source: Daily Dose of Science Blog

Scientists found 700-year-old caribou dung frozen in ice cores removed from icy patches on the Selwyn Mountains in Canada.  To some people, dung may be the last thing they think of as useful for study, but food that animals eat can have tons of viruses in them, including plant matter eaten by caribou.  These viruses can be found in poop after going through the digestive system, and well-preserved DNA and RNA from the viruses can sometimes be sequenced.  Caribou like to hang out on ice patches to avoid biting insects and heat during the summer, so when they poop on the ice, and more ice covers the poop for thousands of years, the virus DNA and RNA from plant viruses or insect viruses (spread by insects attracted to the feces when they were fresh) does stay well-preserved.  In fact, scientists recently recovered a full plant virus genome from the caribou dung that was unlike any present-day plant viruses that are sequenced.  They were able to inoculate a type of tobacco plant with the virus (tobacco is often used for scientific research and is susceptible to many plant viruses), and the virus infected the leaves of the plant!  A partial insect RNA genome was also recovered from the dung.

Since these viruses are from plants and insects, people do not need to worry that they are a health threat for us. However, it is interesting to think that with increased Arctic ice melt, viruses will be released into the environment and can still infect some plants and insects that are exposed to them.

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Lisa Stelzner
I'm a plant biology PhD student studying monarch butterflies in Michigan, but I'm interested in lots of other types of science, too. I am interested in how breeding monarch butterflies choose their habitat based on floral species richness and abundance. Few studies have been conducted on optimal foraging theory when it involves an organism searching for two different kinds of resources, and butterflies are an ideal study system to investigate this, since many species are ovipositing specialists and only lay eggs on one species of hostplant, but are feeding generalists and nectar from a broad variety of flowering forbs.