Practice question

Complete linkage denotes zero recombinant chromosomes observed among progeny indicating loci so tightly adjacent that crossover never occurs between them in examined sample or structural feature like inversion suppresses exchange. All gametes retain parental configurations producing only two phenotypic classes mirroring original coupling phase. Historically Morgan observed near-complete linkage for black body and vestigial in Drosophila without recombinants demonstrating genes reside close together on same chromosome and co-segregate. Modern fine mapping with larger populations may detect rare recombinants revealing small distance even in tight linkage.