Karyotyping

Karyotyping is a laboratory procedure that allows scientists to visualize an individual's chromosomes. It is a key tool in genetics and genomics, used to identify chromosomal abnormalities and to study the genetic makeup of an organism.

Overview

Karyotyping involves the staining and imaging of chromosomes, typically during the mitotic phase of cell division when the chromosomes are most visible. The resulting image, or karyotype, displays the complete set of chromosomes arranged according to their size and shape. This arrangement is referred to as the idiogram.

Procedure

The process of karyotyping begins with the collection of a sample of cells, often from blood, bone marrow, or amniotic fluid. The cells are then cultured in a laboratory to encourage them to divide. Once the cells are in the metaphase stage of mitosis, they are stained and photographed under a microscope. The resulting image is then analyzed, with the chromosomes being counted and arranged according to their size and the position of their centromere.

Applications

Karyotyping is used in a variety of scientific and medical contexts. In prenatal diagnosis, it can detect chromosomal abnormalities such as Down syndrome or Turner syndrome. In cancer research, it can identify chromosomal changes that may be associated with specific types of cancer. In evolutionary biology, it can provide insights into the evolutionary relationships between different species.

Limitations

While karyotyping is a powerful tool, it has its limitations. It can only detect large-scale chromosomal abnormalities and is not capable of identifying smaller genetic changes such as single gene mutations. Additionally, the procedure requires cells to be in the metaphase stage of mitosis, which can be challenging to achieve in a laboratory setting.

See also

• Genetic testing
• Cytogenetics
• Chromosome abnormality