Cytogenetics

The cytogenetic is studying the chromosomes of the human body and the diseases which are related to such body units which can be caused by a number or structure abnormal chromosomes. These studies are carried out by means of microscopy techniques . It is important to remember that chromosomes are structures that are located in the nucleus of the cell and that they are made up of DNA , histones, RNA, proteins, and different types of polysaccharides.

What does cytogenetics study

The cytogenetic is a branch of genetics that focuses on the study of structure , function and behavior of chromosomes . Through the techniques used, the presence of a tumor cell out of 20 normal cells can be identified. The most important advantage of cytogenetic studies is that all chromosomes can be visualized at the same time. This type of cytogenetic study is required to be carried out in the evaluation of those hematological neoplasmsthat they presented some type of alteration when the diagnosis is given. It is a very useful tool used by doctors and scientists to define different diseases related to chromosomes and provides us with information to understand the mechanisms involved in their pathogenesis .

History

The first time chromosomes were observed was in plant cells by Karl Wilhelm von Nägeli in 1842. During the 20th century, genetics began to develop from the concept that chromosomes were responsible for carrying genes . Research on the human karyotype took several years to find out how many chromosomes a normal human cell had . In 1912, Hans von Winiwarter collected 47 chromosomes in spermatogonia and 48 in oogonia. Later in 1921, Theophilus S. Painter demonstrated the presence of the Y chromosomein the testes and defined the total chromosomes as 48 . In 1956, Tjio from Indonesia and Albert Levan from Sweden determined that the number of chromosomes in the human species was actually not 48, but 46 . Ford and Hamerton confirmed this theory. This finding was decisive in the beginning of human cytogenetics .

Applications

Cytogenetic studies have become very important in the diagnosis of neoplasms and malignant hematitis . It is important along with the studies to take into account the patient’s history and laboratory tests . At the same time, cytogenetics helps to characterize the type of leukemia and its prognosis, it is even possible to know the origin of a certain neoplasm . It is key in the discovery of Mendelian or monogenic inherited diseases, multifactorial diseases , mitochondrial and diseaseschromosomal . It can be used to make determinations of hereditary diseases that affect the chromosomes while the baby is still in the mother’s uterus, to determine the sex in genetic diseases associated with sex, and, to know if the parents are carriers of some type of structural alteration .

Conventional cytogenetics

The study of chromosomes by means of G bands is known as conventional cytogenetics .  It is the study that is carried out when it is necessary to identify chromosomal alterations in terms of number and structure, such as, for example, trisomies and monosomies . It is used in the medical field to perform a complete analysis of the karyotype of tumor cells . This type of study requires a certain number of metaphases and does not have the ability to detect submicroscopic changes or reorganizations.of chromosomes. It is for this reason that conventional cytogenetics must go hand in hand with band analysis, fluorescent in situ hybridization or comparative genomic hybridization.

Molecular cytogenetics

Molecular cytogenetics are the studies that are carried out by means of different analyzes using molecular biology tools such as fluorescent in situ hybridization , better known in the field of medicine as FISH . In other words, it is the study and identification of duplications or micro deletions of the genome . Its main contribution is that it has allowed the study of chromosomes with specific probes, making it a powerful diagnostic tool to detect diseases before and after birth, numerical and structural chromosomal aberrations that could not be detected with conventional cytogenetics..

Clinical cytogenetics

Clinical cytogenetics is the study of the human body’s chromosomes , their structure and inheritance , applied to the practice of medical genetics. This branch was the first science to offer a perspective on medical genetics based on human genomes . It detects diseases such as congenital malformations and hemato-oncological disorders.

Human cytogenetics

Human cytogenetics is the science that studies the discoveries about cytogenetics from scientific studies carried out by scientists Tjio, Levan, Ford and Hamerton , who confirmed that the number of human chromosomes was 46, XX in women and 46 XY in men. mens.