Question

A dikaryon is formed when
A)Meiosis is arrested
B)The two haploid cells do not fuse immediately
C)Cytoplasm does not fuse
D)None of the above

Answer 1

Dikaryon is a defect of the cell and has two nuclei. In some fungi, this phenomenon is observed without undergoing cell division, which duplicates their DNA content.

Complete answer:
A dikaryon is a pair of linked but unfused haploid nuclei of a fungus cell capable of participating until their final fusion as independent individuals in repeated cell division. A dikaryon is formed when two haploid cells do not spontaneously fuse.
Karyogamy is delayed in higher fungi and occurs only prior to meiosis. In the mechanism that interferes with plasmogamy and karyogamy, the cells often have two nuclei or Dikaryons (n+n). These cells are called dikaryotic cells. In Ascomycetes and Basidiomycetes, the mechanism is known as Dikaryophase.

For the Dikarya subkingdom, which consists of the Basidiomycota and the Ascomycota, the development of a dikaryon is a plesiomorphic character. The preservation of the dikaryons is encouraged by the creation of croziers in the Ascomycota and clamp connections in the Basidiomycota. Some fungi have, however, developed other methods for preserving the dikaryons in both of these phyla, and thus neither croziers nor clamp ties in either phylum are widespread.

Hence, the correct answer is option (B)

Note: This attribute is most commonly present in the ascogenous hyphae and ascocarp in the Ascomycota, while the mycelium's bulk remains monokaryotic. This is the primary process in the Basidiomycota, with most Basidiomycota monokaryons growing weakly and becoming short-lived.