Chromosome analysis is the scientific examination of genetic material. Comprised of proteins and DNA, human chromosomes provide extensive information about the genetic makeup of individuals. As human understanding of genetics has expanded, careful study and interpretation of chromosome composition has become a vital medical tool. Chromosome analysis can show the presence of genetic abnormalities, and may serve as a road map to potential genetic conditions in both the individual and blood-related family members.
Most humans have 46 chromosomes, 23 from each genetic parent. These are contained in the nuclei of cells throughout the body, and samples for analysis can be harvested from the blood, bone marrow or bodily tissues. Samples are treated over several days to cause chromosomes to expand for easier examination. Analysis typically involves 15-20 samples from one patient, in order to ensure that results are redundant as far as possible. Results are typically interpreted by a doctor or geneticist, in order to properly explain the discovered information to patients.
Chromosome abnormalities can occur for several reasons. As genetic material passes from one generation to the next, chromosomes may accidentally rearrange, making it more difficult for cells to divide equally and sometimes causing reproductive problems. People can also have extra or missing chromosomes, which can lead to a variety of health conditions. Down syndrome was one of the first conditions known to be related to the presence of an extra chromosome. In that case, patients with Down syndrome usually feature a second copy of a chromosome known as “21.”
Animal chromosome analysis began in the early 19th century, but human chromosome analysis went largely unexplored until the 20th century. Since the 1950s, huge advances in the understanding of human genetics have been made by dozens of scientists in different fields of study. Less than a century after human chromosomes were first studied for clues to genetic conditions, the practice of chromosome analysis has become a common way to gather medical information about an individual’s genetic code.
Often, chromosome analysis is performed to determine if a family has a genetic predisposition for certain diseases and health conditions. Some people planning to become parents undergo analysis to determine if future children might be at risk for disabilities or illnesses due to a dormant genetic abnormality. Often, the appearance of an abnormality does not guarantee that conditions will ever develop or genetically pass to offspring. It is important to consult with doctors who have expertise in genetics, in order to accurately interpret analysis results.