Overview On Available Fish Banding Methods

Five different FISH banding methods are available at present, which differ in their probe composition as well as in their banding resolution:

1. The cross-species color banding (Rx-FISH) or Harlequin FISH probe set provides the lowest resolution of 80-90 bands per haploid human karyotype and consists of flow-sorted gibbon chromosomes.[6] A set of 110 human-hamster somatic cell hybrids (split into two pools and labeled with two fluorochromes), when hybridized to human chromosomes, leads to about 100 ''bars'' along the genome. This pattern has been called ''somatic cell hybrid-based chromosome bar code.''[7] A combination of the latter and the aforementioned Rx-FISH probe set results in 160-chromosome region-specific DNA-mediated bands in human karyotypes.1-7-1

2. Spectral color banding (SCAN) was described ex-emplarily for one chromosome up to the present. Eight microdissection libraries were created along chromosome 10 with the goal to obtain a banding pattern similar to GTG banding at the 300-band level.[8]

3. A chromosome can be characterized as well by a specific signal pattern produced by yeast artificial chromosome (YAC) clones. The first attempts to label each chromosome by subregional DNA probes in different colors were performed by Lichter et al.[9] and Lengauer et al.[10] A YAC-based chromosome bar code was created especially for chromosome 12 but not for the entire human karyotype yet (for review, see Refs. [2] and [3]). A resolution of up to 400 bands can be achieved, depending on the number of the applied probes.

4. The Interspersed PCR multiplex FISH (IPM-FISH) approach[11] has an approximate resolution of 400 bands per haploid karyotype, mainly dependent on chromosome quality. In IPM-FISH, whole chromosome painting probes are used, which are modified by interspersed PCR, leading to a 24-color FISH painting plus an R-band-like pattern.

5. The high-resolution multicolor banding (MCB) technique is based on overlapping microdissection libraries producing fluorescence profiles along the human chromosomes, and was initially described exemplarily for chromosome 5 in 1999.[12] MCB allows the differentiation of chromosome region-specific areas at the band and subband levels at a resolution of 550 bands per haploid karyotype. As the number of pseudocolored bands per chromosome can freely be assigned using the isis software (MetaSystems, Altlussheim, Germany), a resolution higher than that of GTG banding of the corresponding chromosome can be achieved (e.g., up to 10 MCB bands for chromosome 22 equal 800 bands per total haploid karyotype).[2] An MCB set of approximately 140 microdissection libraries covering the entire human genome was described in 2002.[13] A DNA-specific MCB pseudocolor banding pattern on normal human chromosomes is depicted in Fig. 1. A YAC/bacterial artificial chromosome (BAC)-based MCB set turned out to be of lower quality.[14] However, a combination of microdissection-based MCB probes sets with locus-specific or breakpoint-specific probes is very

13 14 15 16 17 18

Fig. 1 MCB pseudo-color pattern for all 24 human chromosomes in a ~ 380-band level. Two homologue autosomes and one gonosome each are presented. The chromosomes depicted here have been put together from 24 different MCB experiments. (View this art in color at www.dekker.com.)

promising.[15] Recently, the simultaneous use of all human MCB libraries in one hybridization step for the characterization of complex karyotypes was per-formed.[16]

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

Get My Free Ebook


Post a comment