- 1. Transposition of two segments between nonhomologous chromosomes as a result of abnormal breakage and refusion of reciprocal segments. 2. Transport of a metabolite across a biomembrane. [trans- + L. location, placement, fr. loco, to place]- bacterial t. the movement of bacteria or bacterial products across the intestinal membrane to emerge either in the lymphatics or the visceral circulation.- balanced t. t. of the long arm of an acrocentric chromosome to another chromosome; an individual with a balanced t. has a normal diploid genome and is clinically normal but has a chromosome count of 45 and as a result of asymmetric meiosis may have children lacking the genes on the translocated segment or have them in trisomy.- group t. a form of active transport across a biomembrane in which the transporting molecule is altered in the course of the transport.- robertsonian t. t. in which the centromeres of two acrocentric chromosomes appear to have fused, forming an abnormal chromosome consisting of the long arms of two different chromosomes with loss of the short arms. A carrier of a balanced robertsonian t. has only 45 chromosomes but near normal chromosomal complement and a clinically normal phenotype; however, he or she is at risk of having a child with unbalanced chromosomal complement. A person with an unbalanced robertsonian t. is trisomic for the long arm of the chromosome. SYN: centric fusion. [W.R.B. Robertson, U.S. geneticist, *1881]- unbalanced t. condition resulting from fertilization of a gamete containing a t. chromosome by a normal gamete; if this abnormality is compatible with life, the individual would have 46 chromosomes but a segment of the t. chromosome would be represented three times in each cell and a partial or complete trisomic state would exist.
* * *1) transfer of part of a chromosome to a different position esp. on a nonhomologous chromosome esp the exchange of parts between nonhomologous chromosomes2) a chromosome or part of a chromosome that has undergone translocationtrans·lo·cate -'lō-.kāt vb, -cat·ed; -cat·ing
* * *n.(in genetics) a type of chromosome mutation in which a part of a chromosome is transferred to another part of the same chromosome or to a different chromosome. This changes the order of the genes on the chromosomes and can lead to serious genetic disorders, e.g. chronic myeloid leukaemia.
* * *trans·lo·ca·tion (trans″lo-kaґshən) [trans- + L. locus place] 1. movement of a substance from one place to another; used particularly for movement within a biological fluid or across a biological membrane. 2. movement of the ribosome from one codon to the next along the messenger RNA (mRNA) in protein synthesis. 3. a structural chromosome aberration in which one segment of a chromosome is transferred to a nonhomologous chromosome, the result of breakage of both chromosomes with repair in abnormal arrangement. Called also interchange. Abbreviated t. See insertion (def. 3), and see illustration at aberration.
Medical dictionary. 2011.