Parasexual cycle was first discovered by Pontecarvo and Roper in 1952 Aspergillus nidulan.s.
It is also known as somatic recombination.
Parasexual cycle is defined as a cycle in which plasmogamy, karyogamy and meiosis take place but not at specified time or specified points in the life cycle of an organism.
According to Pontecarvo (1958), parasexual cycle in A. nidulans involves the following steps:
(i) Formation of heterokaryotic mycelium
(ii) Fusion between two nuclei (kaiyogamy)
[a] Fusion between like nuclei
[b] Fusion between unlike nuclei
(iii) Multiplication of diploid nuclei
(iv) Occasional mitotic crossing over.
(v) Sorting out of diploid nuclei
(vi) Occasional haploidisation of diploid nuclei.
(vii) Sorting of new haploid strains.