Question

In Paramecium, both autogamy and conjugation are sexual processes because of

• A. Fusion of two haploid nuclei
• B. Involvement of two individuals
• C. Recombination of genetic materials
• D. Rejuvenation

Answer 1

Answer: (C)

Recombination of genetic materials

In conjugation, direct contact between the donor and recipient Paramecium leads to the establishment of a cytoplasmic bridge between them and transfer of part or all of the donor genome to the recipient. Conjugation in Paramecium is shown in the picture above. In autogamy, the same type of reorganization as conjugation is effected by a single cell. At the time of first micronuclear division, the two small micronuclei increase tremendously in size and it is followed by 2 more divisions which result in the formation of gamete nuclei. As these nuclei are exact duplicates of those formed in conjugation, they are interpreted as meiotic divisions. Two of these nuclei fuse to form synkaryon which will divide 2 more times to form 4 nuclei. Two of them become macronuclear anlagen while the other two become functional micronuclei. These nuclei are distributed to two daughter cells. Since autogamy involves maturation and fertilization and hence may be regarded as a sexual process.

Thus, the correct answer is option C.