centric fusion

ro·bert·so·ni·an trans·lo·ca·tion

translocation 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 translocation 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 translocation is trisomic for the long arm of the chromosome.
Synonym(s): centric fusion
[W.R.B. Robertson, U.S. geneticist.]

ro·bert·so·ni·an trans·lo·ca·tion

(rob'ĕrt-sō'nē-ăn tranz'lō-kā'shŭn)
Translocation 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; if the translocation is balanced, the individual is clinically normal but a carrier of the translocation; if the translocation is unbalanced, the individual is trisomic for the long arm of a chromosome.
Synonym(s): centric fusion.
[W.R.B. Robertson, U.S. geneticist.]

centric fusion

the joining together of two ACENTRIC CHROMOSOMES to produce one METACENTRIC CHROMOSOME.

Robertson,

W.R.B., U.S. geneticist, 1881–.
robertsonian translocation - translocation in which the centromeres of two acrocentric chromosomes appear to have fused, forming an abnormal chromosome. Synonym(s): centric fusion
References in periodicals archive ?
In our case, the breaking point was located in the centromeric region, whose union is called centric fusion (15).
As in all these Micropholcus the chromosomes are biarmed, it is possible that tandem fusions, instead of centric fusion, were implied in the process.
Akodon cursor (ACU) presents variation in diploid numbers (2n = 14 to 16) due to a complex rearrangement involving chromosomes 1 and 3, in which pericentric inversions followed by a centric fusion gave rise to a karyotype with 2n = 15 when in heterozygosis or 2n = 14 when in homozygosis [6,8].
The large Y chromosome in both species likely represents centric fusion between an autosome and a morphologically cryptic Y chromosome, giving rise to a situation of multiple sex chromosomes: [X.sub.1][X.sub.1][X.sub.2][X.sub.2] in females and [X.sub.1][X.sub.2]Y in males (Uyeno and Miller, 1971; Levin and Foster, 1972).
When compared with the karyomorph 2n = 42, these differences are most probably due to a centric fusion.
Chromosome polymorphisms and natural selection in Leptysma argentina (Orthoptera): external phenotype affected by a centric fusion predicts adult survival.
Once a neo-XY system has arisen by centric fusion, it may undergo a further conversion into an X1X2Y system through a Y-autosome fusion, if a second pair of teleo/acrocentric autosomes is available to become incorporated into the sex-chromosome mechanism (White 1973, Hewitt 1979, Castillo et al.
Robertsonian centric fusion has been used to explain chromosome number reductions in Pectinidae.
The Y chromosome originated by the centric fusion of a large neo-Y and a medium-size autosome.
There was a centric fusion involving a long acrocentric X chromosome, the biggest one ofthe set, which is totally heteropicnotic during the first prophase; the biggest of the second group was formed by acrocentric autosomes, giving rise to the biggest element of the set that becomes submetacentric and is now recognized as neo-X.
The drastic reduction in diploid number from 48 chromosomes to 2n = 36 and 2n = 34, respectively, along the presence of large metacentric pairs is evidence of sequential Robertsonian rearrangements or centric fusions (Figures 2(c) and 2(e)).
The most commonly observed rearrangements were centric fusions, tandem fusions and pericentric inversions.