Q.Mention the key features of meiosis.
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Start your 14-day free trial to unlock the full solution →Meiosis has two divisions after one DNA replication, halves the chromosome number, involves synapsis and crossing over, and yields four genetically varied haploid cells.
Key features of meiosis:
- Two successive divisions, one replication:
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DNA replication occurs only once, but the nucleus divides TWICE - meiosis I (reductional division) followed by meiosis II (equational division). Hence a single diploid cell produces four cells.
- Reduction of chromosome number:
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Meiosis reduces the chromosome number from the diploid (2n) to the haploid (n) number. This maintains a constant chromosome number across generations after fertilisation.
- Pairing of homologous chromosomes (synapsis):
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During prophase I, homologous chromosomes come together and pair, forming bivalents (tetrads).
- Crossing over and recombination:
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Segments are exchanged between non-sister chromatids of homologous chromosomes at points called chiasmata (crossing over), producing new gene combinations (genetic recombination/variation).
- Formation of four haploid cells: …
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