Practice question

During sexual cycle diploid nucleus undergoes DNA replication producing four chromatids per chromosome pair followed two meiotic divisions reductional then equational segregation. End result four haploid nuclei each containing recombined chromosomes with new allele combinations. In ascomycetes each nucleus forms ascospore wall, so ascus contains four meiotic products collectively called tetrad. Number four corresponds to four chromatids originally present after replication and division. Even when post-meiotic mitosis creates octad eight spores, underlying genetic composition still four distinct chromatid products, each duplicated mitotically preserving segregation ratios.