Mechanism of reciprocal translocations

Nonhomologous chromosomes exchange parts without loss of genetic content. When meiotic division occurs, the normal and translocated chromosomes can only pair by forming a quadrivalent structure. The resulting segregation products include a normal chromosome complement, a balanced rearrangement, and four unbalanced products. The unbalanced products can be subdivided into two products with correct and two products with incorrect centromere segregation. The latter event is rare and associated with decreased viability.