Alan Roper, 2000

"there was an intellectual vigour generated by Ponte and by the flow of distinguished visitors whom he attracted."

The development of the ascomycete fungus Aspergillus nidulans as a convenient genetical tool led to the discovery in 1950 with Alan Roper of asexual reproduction, the parasexual cycle, in fungi. The consequences are similar to what happens in sexual reproduction, crossing over and recombination of genes. Pontecorvo realized that this phenomenon could be used to figure out the arrangement of genes on chromosomes.

The Parasexual Cycle was successfully patented in 1954 and was the first patent to be issued in any jurisdiction for a natural biological process.