- 1). Researchers start the karyotype by first isolating and staining chromosomes and then placing them under a microscope.
- 2). Through the microscope, a picture is taken. The picture must be cut up, separating the individual chromosomes.
- 3). The chromosomes are then rearranged according to size from largest to smallest.
- 4). A medical professional known as a cytogeneticist then examines the rearranged chromosomes and looks for abnormalities, such as too many, too few, missing pieces, or mixed up pieces. For example, a karyotype that has three copies of chromosome 21 has one too many. That person would have the genetic disease known as Down syndrome, or trisomy 21.
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