Question

Parasexuality was discovered in
A. Bacteria
B. Virus
C. Fungi
D. None of the above

Answer 1

Hint: Parasexuality, also known as Somatic recombination is the process of recombination of genes from different individuals without meiosis and these recombinant genes are transferred on to the offspring. The microorganisms that are considered just like plants or from which plants evolved are the ones who represented this phenomenon for the first time.

Complete answer:
Guido Pontercorvo and J A Roper discovered this process of parasexulatily in Aspergillus nidulans for the first time in 1952. In this process the genetic material is transferred to the next generation without any sexual reproductive organ or meiosis. It is initiated by the development of hyphae during which the cytoplasmic content along with the nuclei occupy a cell which later on fuse with a cell having a different nuclei resulting in production of a diploid nuclei. This process leads to genetic recombination to occur along with crossing over followed by haploidization during which the cells are divided into haploids. Crossing over leads to the exchange of genes and haploidization leads to the mitotic nondisjunction that forms haploid cells.
This process includes four stages –
1. Diploidization – In this stage two haploid cells diffuse to form a diploid cell.
2. Mitotic chiasma formation – It is the breaking and rejoining of non-sister chromatids of the homologous chromosomes. This leads to the formation of a hybrid of the parental genetic material.
3. Haploidization – When the haploid nucleus divides which leads to nondisjunction of chromosomes. Due to this the cells get aneuploidy – uneven number of chromosomes being distributed.
Thus, the right option is C.

Additional information:
- Many species of filamentous fungi are known to exhibit parasexuality like –Fusarium, Penicillium, Verticillium, Ustilago, Candida and many more.
- Microbiologists use parasexuality as an industrial tool to develop different strains with desired combinations of chromosomes.
- Phycomycetes fungi like Olpidium do not show parasexuality and reproduce either sexually or asexually.

Note: Parasexuality is being observed in several fungal species which are used in industries due to which new strains of fungi keep on forming on their own naturally and sometimes these new strains are of better qualities than their parents.