Practice question

Reciprocal translocation involves two-way exchange of terminal segments between non-homologous chromosomes. Two double-strand breaks occur, one in each chromosome, and fragments swap positions, creating derivative chromosomes with new juxtaposition of loci. No net loss occurs in balanced form, but pairing at meiosis forms quadrivalent cross-shaped figure. Segregation can be alternate producing normal or balanced gametes, or adjacent-1 and adjacent-2 producing duplicated deficient gametes. Phenotypic consequences arise from unbalanced segregation in offspring, causing partial trisomy and monosomy and frequent miscarriage, infertility, or congenital anomalies.