The translocation is a chromosomal exchange of material between different Chromosome S.

• If the translocation does not involve a loss of Gène, it is known as balanced . It there not of direct consequence for the first individual reached by the translocation but there is a risk of Trisomie and partial monosomy for the descent if this deterioration touches a germinal cell.

• If the translocation modifies a gene, it is known as unbalanced and there is a risk for the first individual reached by this translocation.

Reciprocal translocation

The carrier of such a translocation has a noted chromosomic chart: 46, XY, T (4,20).

The carrier of a reciprocal translocation in its genome will create during the meiosis of its gamètes quadrivalent in the place of bivalent. The quadrivalent one is, for example if the translocation took place between chromosome 4 and 20, the association of single chromosome 4, chromosome DER (4) (old chromosome 4 having undergoes the translocation), of chromosome DER (20) and of single chromosome 20, this can pose problem during the segregation of the chromosomes at the end of the first division of meiosis.

• Indeed it can have there a segregation putting in the same cell girl, chromosomes 4 and 20 on the one hand, and in the other cell girl chromosomes DER (4) and DER (20). If the child to be born is resulting from the first gamète quoted, then its chromosomic chart will be normal, if the child to be born is resulting from the spoiled second quoted, then it will have the same chromosomic chart as his/her relative reached: 46, X., T (4,20)
• the segregation can be done according to line 1 or line 2, in these cases they will have disorder there genomic important, however the weaker they will be, the more they will be viable.

Translocation robertsonnienne

Anomaly of structure characterized by fusion of two chromosomes acrocentric (type of chromosomes having at the end of their short arm a condensed mass called satellite; this one is attached to the chromosome by a secondary zone of restriction).

It will result from this translocation a chromosome with the two long arms of the chromosomes acrocentric, and a chromosome with the two short arms of the chromosomes acrocentric, that will be eliminated with the following mitosis. The carrier of such a translocation has a noted chromosomic chart: 45, XY, DER (14; 21), if for example the translocation took place between chromosomes 14 and 21.

The carrier of a translocation robertsonienne will create in its gamètes, with the following meiosis trivalent in the place of bivalent. That Ci will be for example if the translocation took place between a chromosome 14 and 21, the association of the single chromosome 14, single chromosome 21, and chromosome DER (14,21) which is the product of the translocation, this can pose problem during the segregation of the chromosomes at the end of the first division of meiosis.