1. Fishing for Chromosomes
Ankur Shah

2. Chromosome Structure 23 pairs of chromosomes (22 autosomes)
p and q arms; centromere and telomere
Normal karyotypes: 46,XX and 46,XY
Prophase & metaphase chromosomes consist of 2 identical sister chromatids (held together by the centromere)
Each germ cell contains only 23 chromosomes (1 member of each pair)

3. Introduction to Karyotypes
A karyotype is a picture of an organism's genetic make-up in which the chromosomes of a cell have been stained so that the banding pattern of the chromosomes appear.
Cells in Metaphase are stained to show distinct parts of the chromosomes
The cells are then photographed through a microscope and enlarged
The chromosomes are cut from the photograph and arranged according to size, shape, centromere position, and banding patterns.

4. A Sample Cell during Metaphase

5. Normal Male Karyotype (46,XY)

6. Chromosome groups: A - G

7. Chromosome Abnormalities - Aneuploidy:
N = 23 chromosomes
Euploidy:
Diploid (2n)
Triploid (3n)
Tetraploid (4n)
Aneuploidy
A chromosome number that’s not an exact multiple of n (23 chromosomes)
Due to meiotic non-dysjunction
E.g. Trisomy (T13, 18, 21); Monosomy (Turner syndrome)

8. Aneuploidy - Trisomy 13

9. Aneuploidy - Trisomy 18

10. Triploid Karyotype (69, XXY)

11. What is FISH?
Fluorescent In
Situ
Hybridization

12. Why Use Fish? Fast Can utilize Interphase Cells Translocations
Deletions
Rearrangements
Makes Karyotyping much easier

13. The Downside of Fishing
Requires large number of cells ( )
Expensive!
Can only search for one defect at a time

14. Examples of Fish

15. More Examples of Fish

16. Just a few more

17. Hey that isnt Fish!
THE END