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| in situ hybridization (ISH) | | in situ hybridization (ISH) | ||
| good way to find gene losses and duplications (one colour) and gene splits and fusions (two colours); | | '''intermediate resolution''' - better resolution than karyotyping for the specific target of the given ISH; good way to find gene losses and duplications (one colour) and gene splits and fusions (two colours); can be done on [[formalin]] fixed paraffin embedded tissue | ||
| target specific (if the target is wrong no information is gained ''or'' one is mislead by the negative result); NOT good for "going on a fishing expedition", i.e. looking for changes when one doesn't quite know what is wrong | | '''target specific''' (if the target is wrong no information is gained ''or'' one is mislead by the negative result); NOT good for "going on a fishing expedition", i.e. looking for changes when one doesn't quite know what is wrong | ||
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| karyotyping | | karyotyping | ||
| finds large scale gains, losses | | finds '''large scale changes''' (gains, losses, rearrangements); good for "going on a fishing expedition", i.e. looking for changes when one doesn't quite know what is wrong | ||
| low resolution (completely misses small scale changes); requires fresh tissue/cell culture (as it is based on metaphase nuclei) | | '''low resolution''' (completely misses small scale changes); '''requires fresh tissue/cell culture''' (as it is based on metaphase nuclei) | ||
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| PCR + sequencing ''or'' enzyme digestion and electrophoresis | | PCR + sequencing ''or'' enzyme digestion and electrophoresis | ||
| high resolution (can find very small changes, e.g. base pair substitutions); can be done on [[formalin]] fixed paraffin embedded tissue | | '''high resolution''' (can find very small changes, e.g. base pair substitutions) - considered gold standard; can be done on [[formalin]] fixed paraffin embedded tissue | ||
| expensive; thus, limited to small regions | | expensive; thus, limited to small regions ('''target specific'''); enzyme digestion and electrophoresis is a compromise of sorts where one needs to know something about the expected abnormality; (gene) duplications may be difficult to prove; regions with many repeats difficult to sequence | ||
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