Practice question

Second division segregation indicates crossover occurred between gene locus and centromere, keeping allelic differences heterozygous after first division despite reductional segregation of centromeres. Daughter nuclei at end meiosis I still contain both alleles on sister chromatids, so alleles separate only at meiosis II equational division producing alternating spore patterns like AAaa or 2:2:2:2 alternation displaying recombination. Presence SDS demonstrates recombination between centromere and gene, diagnostic for distal position. Frequency SDS increases with gene-centromere distance, allowing calculation centromere linkage and chromosome organization inference accurately.