Caption:
Colour enhanced micrograph of a karyotype of an infertile male. There are 22 pairs of chromosomes and also the gender determining pair (lower right corner). In men, this comprises one X and one Y chromosome. In women, it is made up of two X chromosomes. The Y chromosome carries genetic information responsible for the development of male characteristics. Chromosomes carry genetic information in the form of genes, lengths of DNA that act as recipes for proteins. Karyotypes are an arrangement of chromosomes based on their appearance under a light microscope.