Definition

1. Noun:
   • A stage in cell division: Zygotene is the second stage of prophase I during meiosis, the process of cell division that creates gametes (sex cells). In this stage, homologous chromosomes begin to pair up and align closely in a process called synapsis.

Usage

• Scientific Context: This term is used almost exclusively in cell biology and genetics to describe a specific, microscopic phase of meiosis.
  • During zygotene, the synaptonemal complex starts to form between homologous chromosomes.
  • Researchers observed the zygotene stage under the microscope to study chromosome pairing.

Advanced Usage

• Technical Description: Zygotene is characterized by the initiation of synapsis, where homologous chromosomes (one from each parent) find each other and align gene by gene. This pairing is essential for genetic recombination in the next stage (pachytene).

Variants and Related Words

• Zygotene stage: A synonymous phrase for zygotene.
• Prophase I: The larger phase of meiosis I that includes zygotene, as well as leptotene, pachytene, diplotene, and diakinesis.
• Synapsis: The pairing process that defines the zygotene stage.
• Synaptonemal complex: The protein structure that forms between homologous chromosomes during zygotene to facilitate synapsis.

Synonyms

• Second prophase I stage: A descriptive synonym.
• Synapsis stage: Refers to the key event occurring during zygotene.

Related Terms (Not Phrasal Verbs or Idioms)

• Leptotene: The stage immediately before zygotene, where chromosomes condense.
• Pachytene: The stage immediately after zygotene, where crossing over occurs.
• Meiosis: The overall type of cell division in which zygotene occurs.
• Homologous chromosomes: The paired chromosomes that align during zygotene.

Noun

1. the second stage of the prophase of meiosis