Practice question

Cross revealing types of gametes formed is test cross where individual of interest mated to homozygous recessive tester. Because tester contributes invariant recessive allele, phenotype of each progeny directly reflects gamete received from tested individual, uncovering parental versus recombinant classes and frequencies. Self cross or back cross to dominant parent masks recessive gametes, reciprocal cross compares parental sex effects not gamete content. Test cross therefore provides information about gamete spectrum, recombination frequency and genotype composition essential for linkage mapping. Mastery ensures accurate interpretation of monohybrid and dihybrid progeny arrays, distinguishing dominance interactions from epistasis or linkage effects.