A microcopic look at chromosomes with G-banding.
In cytogenetics, the study of chromosomes and their abnormalities, every chromosomal pair has a G-band pattern that is unique. This allows scientists to recognize specific chromosomes. Chromosomes are found in the nucleus of a cell.
History
G-banding was discovered in the late 1960s. Torbjorn Caspersson and his associates found that every chromosome has an identifiable banding pattern based on band width and order.
Chromosomes
Chromosomes are made of a mixture of protein and DNA. They contain all genetics information. There are 46 chromosomes in every human cell of which 1 through 22 are autosomal pairs and the last pair are the X and Y sex chromosomes.
Purpose
G-banding is a staining used to bring out the patterns in a chromosome for the purpose of counting and classifying. This gives scientists an overall picture of the cell.
Method
There is a very detailed method to staining the slides. The chromosomes must be in metaphase. The slides are prepared days in advance. They must be the right temperature and pretreated with trypsin to induce the bands. The Giemsa solution is time sensitive, and is washed off the slides with water and dried. The slides are checked for over and under banding.
Understanding
Banding patterns are international. There is an agreed system for describing the patterns throughout the world making different chromosomes recognizable anywhere.
Studying Chromosomes
Chromosome study helps us understand diseases. It also helps to identify some diseases or propensity to a disease early, and lets us do something about it. The study of chromosomes and the genetic codes they hold may help find a cure for many diseases.
