New Genome Probes Promise To Unlock The Complexities Of Fungi-Ant Interaction

The story of this paper started a few years ago when I needed to sequence 300 weevils on a tight budget. So I adapted a method previously used, in which we “fish” the parts of a genome that we are interested in by using probes home-cooked in the lab (a genome probe is a single-stranded sequence of DNA or RNA used to search for its complementary sequence in a sample genome). These kinds of probes are costly to purchase, and their commercial version needs dry ice shipping and minus-80ºC preservation. It worked very well for weevils, so we decided to test the method with something that my friend Zhengyang Wang was working on: Ophiocordyceps fungi (aka zombie ant fungus) infecting moths in China. We were looking for the DNA traces of the caterpillars, which, by the time they are collected, are long gone and basically a shell full of fungi. Because almost all of the DNA left is fungal, many methods fail to sequence the caterpillars, but with this method we got their complete mitochondrial genomes. The method is also very cheap and uses widely available reagents.The authors propose that “PCR-based hybrid enrichment” will be useful worldwide, especially in places where it might be hard to get the traditional expensive and finicky probes. The approach allows customization of enrichment probes for any taxa at any number of genomic regions. In particular, since there is no commercially available hybrid enrichment probe set for ants, the authors suggest that the method would be particularly useful in elucidating the identities of innumerable fungal–ant symbiont complexes found across the globe.
August 9. 2024