As an unexpected treat, Angus and Hal get a chance to genotype their American chestnut friends Cassie & Denny. They collect three discs from a leaf of each tree, place them in tiny test tube, and ship them with other samples to Australia. Then a bunch of lab geeks will genotype them (that means reading a portion of their genome, aka genetic code, aka DNA). The data will then be fed into a massive model built by the not-so-evil genius Jared Westbrook (Director of Science at The American Chestnut

Chestnut blight changed everything. Watch how this deadly fungus transformed a once-mighty tree. | The American Chestnut Foundation

One of the greatest ecological disasters the US has ever seen. Chestnut blight wiped out the American chestnut tree in less than 50 years. A tree that once made up nearly 25% of the eastern forests was reduced to a functionally extinct species. The Asian fungus Cryphonectria parasitica was accidentally introduced into the United States in the late 1800s. While a few diseased chestnuts were noted in the 1880s and 90s, it wasn't until 1904 that the pathogen was identified in New York City. From th