Reciprocal translocation

A reciprocal translocation is an exchange of
chromosomal material between two chromosomes.
Since usually no chromosomal material
is lost or added with a reciprocal translocation,
it does not cause clinical signs (i. e., it is
balanced). However, carriers of a reciprocal
translocation may form gametes with unbalanced
chromosome complements. During
meiosis, the chromosomes involved in the reciprocal
translocation take part as usual in the
homologous pairing of meiosis I. Each of the
chromosomes not involved in the translocation
pairs with its homologous partner that is involved
in the translocation. This leads to the formation
of a characteristic quadriradial configuration
of the involved chromosomes. When
these four chromosomes separate (segregation)
during anaphase of meiosis (see p. 116), one of
three possibilities may occur: With alternate
segregation, one gamete receives the two normal
chromosomes, and the other gamete the
chromosomes involved in the translocation,
i. e., it is balanced.