Contribution of Molecular Cytogenetics in Gene Mapping of Band 22.1 on the Long Arm of Chromosome 16

Abstract

The technique known as FISH, relies on the unique ability of a portion of single stranded DNA, known as a probe to hybridise with its complementary target sequence wherever it is located in the genome. The probe is conjugated . with a fluorescent label allowing it to be visualised under ultraviolet light. We have demonstrated the contribution of FISH in mapping 16q22.1 as refined LOH mapping in primary sporadic breast tumour has shown allelic imbalance of SR02 located at this region. The construction of a high resolution map covering 2.8 Mb on 16q22.1 was essential for the identification of disease gene(s) implicated in the development of this tumour. FISH has been used for localising of 22 PAC probes at 16q22.1. This has been performed by the hybridisation of each probe separately on human metaphase preparations of peripheral blood followed by interpretation of the hybridisation signals of at least 15 metaphases.Six out of 22 probes have been proved to be chimaeric, so they were eliminated from our series. We succeeded to prove the localisation of the remaining probes on 16q22.1.