Karyotyping
The word ‘karyotype’ is derived from the Greek word kernel which means content of the nucleus. The process of pairing and ordering all the chromosomes present in an organism is called karyotyping. In other words, karyotyping is simply a technique that is used to examine and analyse the chromosomes in a sample of cells.
The normal human karyotype contains 22 pairs of autosomal chromosomes and one pair of sex chromosomes. Karyotype of women contain two X chromosomes and are denoted as 46XX. Karyotype of men have both X and Y chromosome and are denoted as 46XY.
WHY IS KARYOTYPING DONE?
Karyotyping is done
- To identify and locate the changes in the chromosome number
- To spot the structural abnormalities of the chromosome
- To identify the incorrectly arranged chromosomes.
WHAT ARE THE MOST COMMON SAMPLES EMPLOYED FOR KARTYOTYPING?
Karyotyping can be performed on
- Amniotic fluid
- Bone marrow
- Blood
- Placenta
APPLICATIONS OF KARYOTYPING IN DIAGNOSIS
- Duplications, deletions, translocations and other such abnormalities in the chromosomes can be identified.
- Birth defects of foetus can be identified.
- Chromosomal abnormalities like aneuploidy can be identified e.g Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome)
- Genetic disorders can be identified.
- Karyotyping also helps in gender identification