A deadly fungus has already wiped out 90 species and threatens 500 more but Anthony Waddle is hoping gene replacement could be their salvation

Standing ankle-deep in water between two bare cottonwood trees on a hot spring day, eight-year-old Anthony Waddle was in his element. His attention was entirely absorbed by the attempt to net tadpoles swimming in a reservoir in the vast Mojave desert.

It was “one of the perfect moments in my childhood”, he says.