NEETBotanyCell Cycle and Cell Division
What is the name given to the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes during pachytene stage?
Options
- ARecombination nodules
- BSynaptonemal complex
- CTetrads
- DChromosomal compaction
Correct answer
A. Recombination nodules
Step-by-step solution
During this stage, the four chromatids of each bivalent chromosomes becomes distinct and clearly appears as tetrads. This stage is characterised by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes. Crossing over is the exchange of genetic material between two homologous chromosomes. Crossing over is also an enzyme-mediated process and the enzyme involved is called recombinase.