Kariotüüpi

Kariotüüpi refers to the complete set of chromosomes in a cell or organism. It is an individual's chromosome complement, which is typically arranged in homologous pairs. Humans, for example, have a normal diploid karyotype consisting of 23 pairs of chromosomes, totaling 46 chromosomes. These include 22 pairs of autosomes and one pair of sex chromosomes (XX for females and XY for males).

The karyotype is usually determined by examining a cell during metaphase, when chromosomes are maximally condensed and visible under a microscope. Chromosomes are stained and then arranged in order of size, from largest to smallest, with the sex chromosomes placed last. This ordered display is called a karyogram or idiogram.

Analyzing the karyotype is crucial in genetics and medicine. It can reveal chromosomal abnormalities, such as aneuploidy (an abnormal number of chromosomes, like in Down syndrome, where there are three copies of chromosome 21) or structural rearrangements (like deletions, duplications, translocations, or inversions). These abnormalities can lead to various genetic disorders, developmental issues, and health conditions. Karyotyping is used for prenatal diagnosis, identifying genetic causes of infertility, and diagnosing certain types of cancer.