Definition

1. Noun:
   • The third stage of the prophase of meiosis: In biology, "pachytene" specifically refers to the third sub-stage of prophase I during meiosis, the process of cell division that creates gametes (sperm and egg cells). During this stage, homologous chromosomes are fully paired (a state called synapsis) and genetic recombination (crossing over) occurs.

Usage Examples

• Noun:
  • During pachytene, the paired chromosomes become visibly thicker.
  • Crossing over is a critical genetic event that takes place in the pachytene stage.

Advanced Usage

• Technical Context: The term is used almost exclusively in specialized fields like genetics, cytology, and cell biology.
  • The analysis focused on chromosomal abnormalities detectable during pachytene.

Variants and Related Words

• Pachytene stage: A common synonymous phrase.
• Diplotene: The stage following pachytene in meiotic prophase.
• Zygotene: The stage preceding pachytene in meiotic prophase.

Synonyms

• Pachytene stage: The full technical term.
• Third prophase I stage: A descriptive synonym.

Related Terms and Concepts

• Synapsis: The pairing of homologous chromosomes, which is completed in pachytene.
• Crossing over: The exchange of genetic material between homologous chromosomes, a defining event of pachytene.
• Bivalent: The structure formed by a pair of homologous chromosomes during synapsis, prominent in pachytene.

Noun

1. the third stage of the prophase of meiosis