Practice question

Meiosis is characterised by single round of DNA replication in premeiotic S phase generating sister chromatids followed by two successive divisions. Meiosis I segregates homologous chromosomes, reducing ploidy from diploid to haploid, while meiosis II separates sister chromatids akin to mitosis. Resulting four haploid products carry recombinant chromatids. Descriptions of two replications with one division, single replication with single division or no replication apply to mitosis or abnormal cycles, not canonical meiosis essential for gamete formation and genetic variation. Conceptual clarity supports solving numerical problems involving segregation ratios, recombination frequencies and probability calculations in crosses.