1 FISH Techniques, FISH Probes and Their Applications in Medicine and Biology - An Overview
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much been based on achievements obtained in recombinant DNA technology, microscope hardware (epifluorescence and fIlter technology) as
well as in computer and software technology for the analysis and storage
of data.
The developments of the present day FISH-technology has mainly been
driven by geneticists and pathologists involved in human disease, because
these specialists have had an ever-increasing need for characterizing
genotype-phenotype correlations, a need which is also illustrated by
the development of large worldwide accessible databases harboring clinical as well as genetic information (e.g. OMIM - On Line Medelian Inheritance in Man). These developments were initiated by worldwide biotechnology programs such as the human genome program (HUGO) and the
methods developed within these programs have subsequently been
adopted by other fields in human and veterinary medicine and biology.
The draft sequence of the human genome which was completed in February 2001 (Lander et al. 2001, Venter Je et al. 2001 and references in these
publications) is an important step to further our understanding on how
the human genome is organized, how it functions, how malfunction relates to disease processes and is a fundamental advance in self-knowledge.
Basic principles of FISH
In situ hybridization (ISH) can be defined as the morphologicallocalization of genetic sequences. The objective of ISH is thus to determine the
presence or absence of specific DNA or RNA species and to localize these
species to particular cellular or chromosomal sites (Fig. 1). The identification of specific sequences within cells is achieved by exploiting a fundamental property of nucleic acids, i.e. their ability to anneal to one another
in a specific manner to form hybrids. This is true not only for two complementary strands of DNA but also for RNA-DNA and RNA-RNA combinations as well as hybrids between natural and artificial nucleic acids. By
labeling one of these two strands the annealed hybrids can be detected by a
variety of means, including isotopic and non-isotopic (fluorescent and
non-fluorescent) methods.
The basic requirements ofthe fluorescence in situ hybridization (FISH)
technique are therefore: 1) a probe that is specific for the sequence of interest; 2) fluorescent labeling of this probe to allow appropriate detection;
and 3) a biological specimen with preservation of sufficient morphological
detail to determine the localization of the labeled probe after hybridization.
5
much been based on achievements obtained in recombinant DNA technology, microscope hardware (epifluorescence and fIlter technology) as
well as in computer and software technology for the analysis and storage
of data.
The developments of the present day FISH-technology has mainly been
driven by geneticists and pathologists involved in human disease, because
these specialists have had an ever-increasing need for characterizing
genotype-phenotype correlations, a need which is also illustrated by
the development of large worldwide accessible databases harboring clinical as well as genetic information (e.g. OMIM - On Line Medelian Inheritance in Man). These developments were initiated by worldwide biotechnology programs such as the human genome program (HUGO) and the
methods developed within these programs have subsequently been
adopted by other fields in human and veterinary medicine and biology.
The draft sequence of the human genome which was completed in February 2001 (Lander et al. 2001, Venter Je et al. 2001 and references in these
publications) is an important step to further our understanding on how
the human genome is organized, how it functions, how malfunction relates to disease processes and is a fundamental advance in self-knowledge.
Basic principles of FISH
In situ hybridization (ISH) can be defined as the morphologicallocalization of genetic sequences. The objective of ISH is thus to determine the
presence or absence of specific DNA or RNA species and to localize these
species to particular cellular or chromosomal sites (Fig. 1). The identification of specific sequences within cells is achieved by exploiting a fundamental property of nucleic acids, i.e. their ability to anneal to one another
in a specific manner to form hybrids. This is true not only for two complementary strands of DNA but also for RNA-DNA and RNA-RNA combinations as well as hybrids between natural and artificial nucleic acids. By
labeling one of these two strands the annealed hybrids can be detected by a
variety of means, including isotopic and non-isotopic (fluorescent and
non-fluorescent) methods.
The basic requirements ofthe fluorescence in situ hybridization (FISH)
technique are therefore: 1) a probe that is specific for the sequence of interest; 2) fluorescent labeling of this probe to allow appropriate detection;
and 3) a biological specimen with preservation of sufficient morphological
detail to determine the localization of the labeled probe after hybridization.