Chromosome translocations?

[sam2400]

Does anyone know how a reciprocal translocation can cause chromosome imbalance during meiosis?

[sorin]

it depends on the segregation of the homologous chromosomes whether the reciprocal translocation is balanced or imbalanced. Genetic material my become exchanged (or is already exchanged, if the individual is a carrier of a balanced translocation) in the germline (e. g. translocation between chr 9 and 22 --> cell with each one chrom 9 and 22, and two chrom t(9;22)). If during anaphase 1 one normal and one abnormal chromosome is transferred to a cell this results in a loss/excess of certain genes. This would not be the case if the two normal chrom 9 and 22 or the two abnormal t(9;22) chromosomes are separated together.

[akki313]

After the process of reciprocal translocation between two non homologous chromosomes.. There occur the formation of a cross like structure between those chromosomes because arms of one chromosome is similar to that of two different chromosomes. This cross like structure involves four chromosomes i.e 2 normal chromosomes and 2 mutated chromosomes.

After the formation of cross like structure there occur segregation in 3 ways:
1. Alternate Segregation
2. Adjecent 1 segregation
2. Adjecent 2 segregation

You can refer following image for the whole process.
http://sapientfridge.org/chromosome_cou ... 201-6.jpeg