The pairs are numbered from big to small. The pairs 1 to 22 are the same for man and woman. By special staining bands on the chromosomes can be made visible as a kind of bar-code. Internationally agreements have been made about the numbering of the bands. This makes the medical equation of chromosome disorders the same in whole the world.
Chromosomes contain genetic information.
Although chromosomes can be studied well under a normal microscope, genes cannot be seen. This impregnated ovum partitions many times and all chromosomes partition as well. Chromosome research Research on chromosomes starts with withdrawal of cells. Blood-cells are put into a bottle with a special medium for their cultivation. After that various chemicals are added to make the chromosomes visible.