CHROMOSOME ANALYSIS
- Chromosome analysis
- karyotyping
- metaphase chromosomes of a somatic cell are obtained and photographed
- from this photograph individual chromosomes
- are cut and arranged according to standard classification
- for preparation rapidly dividing cells used are
- lymphocytes from peripheral blood
- most commonly used
- fibroblasts from skin
- bone marrow cells
- chorionic villi
- amniotic fluid cells
- procedure
- approximately 5 ml of venous blood
- collected under sterile condition
- mixed with heparin to avoid clotting
- lymphocytes are separated from red cells
- white cell suspension is then put in culture vial
- vial contains culture media and fetal calf serum that nourish lymphocytes
- it also contains phytohemagglutinin that stimulates cell division in lymphocytes
- culture is then put in an incubator for 3 days
- the cells divide rapidly
- at end of third day colchicin is added
- prevents the formation of spindles
- thus arrests cell division during metaphase
- metaphase chromosome are highly condensed and easily visible
- cells are separated with centrifuge
- treated in hypotonic saline
- causes to swell and chromosomes to separate
- CHROMOSOME BANDING
- G banding
- Q banding
- R banding
- C banding
- Fluorescence insitu hybridization
- centromeric probe
- Chromosome specific unique sequence probe
- Whole chromosome paint probe
- Multicolor Spectral Karyotyping
Discussion