Aquaculture and Biotechnology
This domain links aquaculture production with biotechnology tools. Questions cover fish culture systems, water quality, induced breeding, disease control, recombinant DNA, PCR, ELISA and transgenic animals.
Core rules
- Aquaculture systems: monoculture, polyculture with rohu, catla and mrigal occupying different feeding niches, integrated fish farming and cage culture. Water quality depends on dissolved oxygen, pH, ammonia and temperature.
- Induced breeding: hypophysation uses pituitary gonadotropins to trigger spawning; environmental cues and hapa management support hatching.
- Fish health: bacterial, viral and fungal diseases; prevention through water quality, quarantine and vaccination where available.
- Biotechnology: restriction enzymes cut DNA; vectors carry inserts; transformation introduces recombinant DNA. PCR uses denaturation, annealing and extension with Taq polymerase. Gel electrophoresis separates DNA by size. ELISA detects antigens or antibodies. Transgenic animals carry foreign genes; gene therapy corrects defective genes; stem cells are unspecialised and can differentiate.
Worked example
To detect a specific DNA sequence in a fish tissue sample, extract DNA, add sequence-specific primers, Taq polymerase and nucleotides, and run repeated cycles: denaturation near 94 degrees Celsius, annealing near 55 degrees Celsius and extension near 72 degrees Celsius. Reasoning: each cycle doubles the target region, and the product is visualised as a band after agarose gel electrophoresis.
Traps
PCR needs primers and a thermostable polymerase. ELISA detects proteins, not DNA. A transgenic animal is not the same as a clone. Gene therapy usually targets somatic cells; germline editing raises different ethical issues. Induced breeding uses gonadotropins, not arbitrary hormones.