Translocation reciprocal

Reciprocal Translocations. These can result from the exchange of chromosomal segments between two chromosomes and, depending on the position of the centromeres in the rearranged chromosomes, different configurations will result. 

Petrij F, Dorsman JC, Dauwerse HG, Giles RH, Peelers T, Hennekam RC, Breuning MH, Peters DJ (2000b) Rubinstein-Taybi syndrome caused by a De Novo reciprocal translocation t(2 16)(q36.3 pl3.3). Am J Med Genet 92 47-52... 

As its name implies, a translocation is reciprocal when genetic material is exchanged between two chromosomes. For example, parts of the short arms of chromosomes 2 and 8 could be exchanged (Fig II-3-4). The individual who carries the reciprocal translocation (46,XX,t[2p 8p]) will not usually be affected clinically because he or she has the normal complement of genetic material. However, his or her offspring can inherit unbalanced chromosome material (e.g., a copy of the normal 8 and a copy of chromosome 2 that contains the translocated piece of 8, resulting in a partial trisomy of the 8th chromosome and partial monosomy of the second chromosome [Fig II-3-4]). 

Drosophila melanogaster, reciprocal translocations -H 440 ppm in feed Yoon etal. (1985)... 

Chromosomal abnormalities included the presence of aneuploidy, a second Ph chromosome, and trisomy 8. The loss of one p53 allele by an alteration of the short arm of chromosome 17 was seen in seven patients, and new reciprocal translocations were seen in two patients. In eight cases, multiple cytogenetic abnormalities were also present (40). 

Pelecanos, M. (1966) Induction of cross-overs, autosomal recessive lethal mutations, and reciprocal translocations in Drosophila after treatment with diethyl sulphate. Nature, 210, 1294-1295... 

The first chromosome abnormality found to be associated with a cancer was the Philadelphia chromosome, which arises as a result of a reciprocal translocation between chromosomes 9 and 22 (fig. S4.4). The tumor associated with this translocation is chronic myelogenous leukemia and results from the activation of the c-abl oncogene, which is normally located on chromosome 9. 

The Philadelphia chromosome arises by a reciprocal translocation between chromosomes 9 and 22. Note that the abl protooncogene is moved in the translocation process. 

Valencia et al.1 77 analyzed published reports of mutagens that induced reciprocal translocations, partial chromosomal loss as a result of very large deletions, and... 

Sixty compounds were tested for their ability to induce reciprocal translocations in male germ cells 26 were classified as positive, 8 as negative, and 26 as inconclusively tested. There were 76 compounds reported in tests for chromosomal breakage involving partial chromosome loss 27 were classified as positive, 13 as negative, and 36 as inconclusive. Many of these studies involved less sensitive test systems than are now available and were done at a time when screening was not the objective of the experiment. 

RECIPROCAL TRANSLOCATION An exchange of segments between two non-homologous chromosomes. 

TRANSLOCATION The shift of a portion of a chromosome to another part of the same chromosome or to a different chromosome. (See also RECIPROCAL TRANSLOCATION)... 

Fig. 6. Physical detection of reciprocal translocations. The chromosomes shown are identical to those in Fig. S. Vertical arrows represent recognition sites for a single restriction enzyme horizontal arrows correspond to synthetic oligonucleotide primers and lines below the chromosomes indicate the sizes of restriction or PCR fragments. In (A), the alteration in restriction fragment size as a result of exchange is illustrated. Such alterations can be detected by Southern analysis using the duplicated sequence as a probe. In (B), the production of a PCR product from one of the exchange chromosomes is illustrated. Neither parental chromosome directs synthesis of a PCR product.

Structural and Numerical Alterations. The basic principles underlying in vivo cytogenetic assays are the same as those for in vitro assays, discussed above (Section 25.3.4b). The cell types that are available for the analysis of chromosome alterations are those that are cycling cell populations, such as bone marrow and spermatogonial cells. For acute exposures, analysis of metaphase cells at their first metaphase after S-phase treatment and analysis of all aberration types is appropriate for hazard evaluation. For chronic exposures, it is inappropriate to analyze unstable aberration types the informative approach is to analyze stable types (e.g., reciprocal translocations and inversions) using FISFI. 

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