Computed and positron emission tomography and other sensitive diagnostic methods using instrumental analysis have recently become common clinical practice. One of such promising methods for early diagnosis of various pathologies is a method based on the study and analysis of genetic markers. Modern laboratories have long offered services for the determination of oncomarkers and markers of various pathological conditions in human blood. What are genetic blood markers, how their indications are used, what they are - we will talk about this in this article.
Let's define the concepts
A genetic marker is a label, a nucleotide sequence of a DNA (deoxyribonucleic acid) segment with a known position on a particular chromosome. This is a feature that is convenient for analysis, which allows you to track the nature of the inheritance of traits linked to this marker.
Modern molecular biology highlightsthe following types of molecular genetic markers:
- Plots of structural (coding for certain proteins) genes.
- Protein-coding regions of structural genes.
- Markers for various DNA sequences that are not related to structural genes.
- Microsatellite regions of DNA (short repeats).
Genetics in our life
Since 2003, when the human genome was sequenced (the international project "Human Genome", The Human Genome Project, HGP), genetics has ceased to be a fundamental science, but has entered the scope of its practical application. Research of DNA markers is used today in many branches of medicine and not only.
Genetic analysis is used to detect pathologies in a patient, to study a specific allergic reaction, to assess the risks of developing hereditary pathologies in adults and children (asthma, diabetes, thrombophilia, schizophrenia, epilepsy).
In prenatal (before birth) medicine, it is genetic analysis that makes it possible to identify pathologies in the embryo (Down, Klinefelter, Edwards, Turner syndromes). Genetic markers can determine the causes of infertility and abortion.
Gene diagnostics is widely used in pharmaceuticals. It provides an explanation for the fact that drugs affect people differently. And why the side effects of drugs have a more severe effect on certain categories of people.
Well, besides, genetic analysis todayallows you to determine in which sport your child can achieve the best results, and which diet is right for you.
Molecular genetic diagnostics
This is a rather young diagnostic method for examining a person's personal "code" and allows you to identify viral and bacterial infections, pathological mutations in genes. The identification of genetic markers in the genome allows a fairly accurate assessment of the risk of hereditary and other diseases.
The main advantage of such diagnostics is minimal medical intervention, because every cell of our body (including blood cells) contains a complete set of all our genes. It is blood from a vein that is the most common material for this study, although other biological fluids (saliva, amniotic fluid, secretions) or tissues (mucous scrapings, hair, nails) can be used.
How it's done
In Russia, not all clinics are yet able to offer molecular diagnostics, although this non-invasive examination method with high accuracy of results is already widely used in countries with a developed he althcare system.
The research steps are as follows:
- Sampling of biomaterial from a patient.
- Isolation of DNA or RNA.
- Research on one of the methods of molecular analysis.
- Study and interpretation of the result.
- Conclusion of a geneticist.
Modern technologies
The detection of polymorphism (diversity) in the structure of DNA has many methods in its arsenal, the main of which are the following:
- Molecular cytogenetics method - analyzes DNA-based markers or RFLP markers (Restriction Fragment Length Polymorphism, RFLP). The method uses DNA extraction, obtaining a fragment of it and analyzing it using a DNA spectrum specific to each individual.
- PCR markers. The method uses a polymerase chain reaction (PCR) using specific primers (sections) of DNA with different lengths and nucleotide sequences. The most popular method in molecular diagnostics.
- Fluorescent DNA hybridization method (FISH). This method works with atypical DNA regions located in a specific locus of the chromosome. It is this method that is used in the detection of oncological pathologies (tumor markers), in prenatal diagnosis (markers of hereditary diseases of the fetus).
- Microchipping method. In this case, fluorescently labeled sections of the patient's DNA are compared with samples on microarrays. Widely used in cardiology (genetic markers of thrombogenic risk) and oncology.
When it matters to the patient
There are situations when recourse to genetic analysis becomes vital, namely:
- When an accurate diagnosis is needed. For example, when determining allergens, viral infections.
- When prevention can prevent the development of pathology. For example, with a positive test for geneticmarkers of thrombophilia (a tendency to form blood clots in the bloodstream) lifestyle adjustments are possible to prevent pathology.
- When the patient's life depends on the effectiveness of treatment. This is exactly what happens when assessing the impact of therapy on the course of oncological diseases.
When it matters for the future
An important area of genetic analysis is risk assessment when planning or having a baby. So future parents can study genetic compatibility and assess the risks of hereditary pathologies in offspring. Methods of molecular genetic diagnostics can examine the condition of the fetus during pregnancy, identify dangerous syndromes and developmental pathologies.
It is possible to diagnose diseases in a born baby and assess the risks of their development. For example, in the presence of genetic markers of diabetes mellitus identified in a child, it is quite possible to adjust nutrition in order to prevent the development of non-hereditary forms of diabetes.
In addition, these methods are used with a high degree of probability in determining paternity and motherhood.
Tumor markers in the fight against cancer
The realism of modern society with its polluted environment and the presence of bad habits gives a rather disappointing prognosis for oncological pathologies. And the main problem of high mortality among patients of oncological dispensaries is the detection of the disease at its late stages.development.
It is the genetic markers that are characteristic in the presence of an oncological process that can detect pathology in the early stages, which significantly increases the survival rates of patients. Tumor markers are biological characteristics that affect the clinical course of the oncological process and its prognosis. In addition, a blood test for genetic markers of oncopathology makes it possible to track the response of the patient's body to therapeutic effects.
Genetics on guard of the law
DNA doesn't lie. It is on this that the work of modern forensic geneticists is based. Comparative analysis of DNA markers from crime scenes with a database is today one of the priority areas in the investigation of serious crimes.
16 DNA markers and a sex marker are used in forensic genetics. Recent advances in the field suggest the race, height, and even appearance of the perpetrator.
However, despite the successes, there are mistakes in judicial practice today. But no one is safe from them.
