Macronucleus:
- Primary nucleus
- Responsible for cellular activities, including growth, reproduction, and metabolism
- Polyploid, containing multiple copies of the genome allowing efficient gene expression
- Controls processes necessary for cell maintenance.
- Contains highly amplified genes required for cell division.
- Has limited genetic diversity due to frequent gene rearrangements.
Micronucleus:
- Smaller nucleus, often located near the macronucleus.
- Contains a single copy of the diploid genome
- Acts as a germline nucleus involved in sexual reproduction and genetic exchange.
- Undergoes meiosis during conjugation, a sexual process where genetic material is exchanged.
- It ensures genetic diversity and facilitates adaptation.
- Responsible for passing genetic information to offspring during cell division.
- Genetically stable, serving as a source of genetic material for macronucleus.
This dual-nuclear system provides ciliates with functional compartmentalization. The macronucleus supports daily cellular activities, while the micronucleus preserves genetic information and facilitates genetic diversity through sexual reproduction.
