Question

Why have some biologists called zygotene a zipper stage?

Answer 1

Zygotene:

1. Zygotene is the second stage of prophase-I observed in meiosis I.
2. Before the zygotene stage, the chromosomes condense into long strands and appear threadlike.
3. During zygotene, the homologous chromosomes pair up in synapsis.
4. Synapsis occurs at the ends of chromosomes and is conducted by the synaptonemal complex, a complex of proteins.
5. The pairing up of chromosomes occurs in a zipper-like fashion.