CBSE Class 9 Answered

A karyotype is an organized profile of a person's chromosomes. In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest. This arrangement helps scientists quickly identify chromosomal alterations that may result in a genetic disorder.

To make a karyotype, scientists take a picture of someone's chromosomes, cut them out and match them up using size, banding pattern and centromere position as guides.

Any cell that contains a nucleus can be used to make a karyotype. However, white blood cells seem to work best for human karyotypes. After the cells are cultured, they are killed by using a drug that halts mitosis, and the chromosomes are then stained, observed, and a size order chart is produced.

A karyotype can be used to detect extra or missing chromosomes, chromosomal rearrangements, or chromosomal breaks.