Fish And Genetic High-resolution Study Of The Physical Positioning

Molecular Cytogenetics,especially with the establishment,further improvement and development of fluorescence in situ hybridization, overcomes the limitation of conventional cytogenetics and molecular genetics. It has become a powerful tool for insight of genetic diseases and human genome. FISH technique improved the detection of numerical and structural aberration of chromosomes and dramatically sped up gene mapping.A case of complicated chromosome aberration was studied by FISH technique. The female patient with primary amenorrhea had a karyotype 46, X, del(Xq24)(7.1 %)/47, X, del(Xq24), +mar(81.4%)/48, X, del(Xq24), +mar, +mar(7.1%)/49, X, del(Xq24), +mar, +mar, +mar(1.4%)/50, X, del(Xq24), +mar, +mar, +mar, +mar(1.4%). It was priliminarily revealed that the marker chromosomes were from a segment of Xq24 → ter and with different shapes. With X chromosome specific probe in FISH,It was showed that the supernumerary marker chromosomes derived from chromosome X in fragments or rings,each of which contained a centromere.To determine the true rate of aneuploidy and to elucidate the mechanism of aneuploidy,the sperms were decondensed for FISH analysis. It was found that the disomic frequencies of chromosome X was 0.208%. A new decondensation method was developed by trypsin treatment. The basic morphology of sperm was maintained.