The document details the fluorescent in-situ hybridization (FISH) technique used in cytogenetics, developed in the early 1980s, which employs fluorescent probes to identify specific DNA and RNA sequences in chromosomes. Protocols for FISH include preparation of probes, hybridization, and visualization under a microscope, with applications in genetic counseling, disease diagnosis, and evolutionary studies. FISH is particularly useful for detecting specific genetic conditions and evaluating gene presence or absence across different species.

1. FISH FLOURESCENT IN-SITU HYBRIDIZATION
NARENDRA YADAV
PAPER 3 UNIT 2

2. INTRODUCTION
 FISH is a cytogenetic technique that uses fluorescent probes that bind to
only those parts of the chormosomes with a high degree of sequences
complementarity.
 Fluorescent probe-DNA complex can be studied under fluroscent
microscope.
 Developed by the biomedical researchers in early’ 1980s.

3. Protocol Outline
 Preparation of the fluorescent probes
 Denaturation of the probe and the target
 Hybridization of the probe and the target
 Detection

4. DENATURE OF
DNA
DENATURE OF
PROBE
LABELLING WITH
PROBE
HYBRIZATION OF DNA-
PROBE
DETECTION

5. Flourescent labled organism

6. MicroRNA(green) and mRNA(red) visualization in
differentiating C1C12 cells

7. Probes
 Complementary sequences of target nucleic acids
 Designed against the sequence of interest.
 Probes are tagged with fluorescent dyes like biotin, fluorescein,
Digoxigenin
 Size ranges from 20-40 bp tO1000bp.

8. PROBES
 Stellaris(R) RNA FISH probes.
 Fiber FISH.
 Q-FISH.
 Flow-FISH.

9. APPLICATION
 Use to detect and localize the presence and absence of the specific DNA
sequences on chormosomes.
 FISH often used for finding specific features in DNA for use in genetic
counselling, medicine, and species identification.
 FISH can also be used to detect and localize specific RNA target (mRNA,
IncRNA, miRNA) in cells.
 Also used to detect circulating tumor cells, and tissues samples.

10. Continue…
 Diseases that are diagnosed using FISH include Angelman syndrome,
22q13 deletion syndrome,, acute lymphoblastic leukemia, Cri-du-
chat, and Down syndrome.
 FISH can also be used to compare the genomes of two biological
species, to deduce evolutionary relationships.

11. BIBLIOGRAPHY
 GOOGLE-IMAGES
 WIKIPEDIA

12. THANK YOU