Last summer I interned at the Genetics Laboratory, Department of Assisted Reproduction and Genetics, Jaslok Hospital. Here is a powerpoint of my hands on experience of karyotyping blood sample from the stage of culture set-up to chromosome analysis

1. Observership
at
Jaslok Hospital
By Kush Puri
Cathedral & John Connon School

2. About the Observership
• Location: Genetics Laboratory, Department of Assisted Reproduction and Genetics at
Jaslok Hospital
Tasks Completed
• Observed routine Cytogenetic diagnostic techniques on various human tissues such as
peripheral blood, bone marrow, amniotic fluid and chronic villi from products of conception.
• Hands on experience of karyotyping blood sample from the stage of culture set-up to
chromosome analysis
• Observed FISH (Fluorescence in situ hybridisation) set up, hybridisation, post hybridisation
washes and analysis.

3. Techniques
• Cytogenetics- Study of chromosomes and their abnormalities
• Karyotyping and FISH- used to diagnose genetic diseases.

4. Karyotyping
• Duration: 12 day process
• Took my own blood sample and carried out the entire process.

5. Method for Karyotyping
• Planting: Culture the tissue for appropriate amount of time (usually 48 to 72
hours).
• Harvesting: Add a spindle poison (we used colchicine) to “arrest” the cells in
metaphase. The is because chromosomes are maximally condensed in
metaphase and thus easiest to see. Then add a hypotonic solution to swell up the
cells.
• Washing: Wash the cells
• Dropping: Drop the sample onto the slide from a height
• Banding: Stain with designated nuclear stain. This helps to identify individual
Chromosomes. (Giemsa banding/G banding done in this case)
• Analysing: Capture images of slides under microscope and using software
arrange the chromosomes into a karyotype.

6. Karyotyping
Day 1: Planting Process

7. Karyotyping
• Day 4: Harvesting

8. Karyotyping
• Day 5: Washing

9. Karyotyping
• Day 7: Dropping

10. Karyotyping
• Day 8: Banding

11. Karyotyping
• Day 9: Analysing

12. Sample of My Chromosome Analysis

13. FISH
• Fluorescence In Situ Hybridisation
• Take DNA probe that is complementary to the
selected region on the chromosome.
Denature the probe and chromosome
sample.
• Hybridization takes place for 3 hours, or
overnight. Washing is then done. Observe
coloured signals under fluorescent
microscope. Capture image. Chromosome
deletions, aneuploidies (duplications) and
translocations (rearrangements) can be
detected.
• A specific chromosome is looked at, which
gives the observer some idea of which
disease they’re testing for.

14. DNA extraction
• Some diseases can only be
diagnosed on a molecular level
(not via chromosomes). Thus
using the patient’s DNA, one can
test for microdeletions.
• PCR- polymer chain reaction. A
specific gene is located, and that
gene is replicated.

15. Letter from Jaslok Hospital