WHAT’S HAPLOIDING, HOT STUFF?: The hermaphroditic (left) and male (right) forms of the haploid gametophytes of Ceratopteris fernsJODY BANKS
In the mid-1990s, Jody Banks of Purdue University was mutating the genomes of ferns using dimethyl sulfate (DMS) and screening for changes in how the plants determined their sex. Ferns can grow as either males or females (the latter are really hermaphroditic, and in the absence of males can make a few sperm in order to self-fertilize). Normally, Ceratopteris richardii ferns grown alone develop into females, but plants grown near genetically identical spores develop into males.
“The female secretes a pheromone telling others to be male,” Banks explains. “If the female [pheromone] goes away, the male will switch back to female. It’s really cool.” This allows plants to outcross when they are near other developing ferns that respond to the pheromone—thought to be a type ...
