translocations - translocations An unbalanced translocation...

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translocations An unbalanced translocation may arise spontaneously and is also likely to arise as an offspring of a balanced carrier. There are likely to be symptoms which may be severe. Their exact nature will be unpredictable. Such translocation chromosomes are extremely useful to science in helping to pinpoint genes resposible for the conditions expressed by their bearers. Robertsonian Robertsonian translocations are a special case of 'almost balanced' translocations. Robertsonian translocations involve any two out of chromosomes 13, 14, 15, 21 and 22. These chromosomes are all acrocentric , that is, the centromere is very close to one end. The short arms contain few, if any, genes except for many tandemly repeated copies of the ribosomal RNA genes. Every diploid cell thus contains 10 copies of the block of repeated genes. A Robertsonian translocation is a fusion between the centromeres of two of these chromosomes with loss of the short arms forming a chromosome with two long arms, one derived from each chromosome. The loss of the short arms
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translocations - translocations An unbalanced translocation...

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