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It is often said that there are no two identical people in the world, and each is unique and differs from others in everything: appearance, voice, inclinations, height. What does it all depend on? The human genetic code is responsible for this – it is it that contains all information about the organism and determines not only visible features, but also those that cannot be seen with the naked eye.
Genetic code – what is it?
Contrary to appearances, the genetic code is not the same as DNA. Its basic unit is a codon, or three nucleotides, which are designated by an amino acid in a protein. There are 4 nucleotides, namely: adenine, guanine, cytosine and lost / thymine – 64 different codons can be formed from them. However, it is always possible to indicate which of the codons is first and last. Besides the codons, there are also exons and introns.
The genetic code is non-overlapping. This means that the individual codons do not overlap. Moreover, the genetic code is also comma – this means that there are no null particles in the code and there are also no gaps between them. When the genetic code is degenerate, one amino acid can be marked with several codons – yet one codon always means only one amino acid.
What are the characteristics of the genetic code?
The genetic code is still the subject of much research. However, the current state of knowledge allows us to state that it is triple, i.e. it takes three nucleotides to form a codon – codons create an individual network of characters for each person. The genetic code is unique, which means that one codon is assigned one amino acid. Another feature of it is collinearity – the arrangement of amino acids in a protein accurately reflects the arrangement of codons in template RNA.
An interesting feature of the genetic code is its universality. A huge number of combinations can be made from nucleotides and codons – in this respect it can be compared, for example, with an alphabet. This means that there are no two identical people in the world – each of us has a different character, appearance and physiological predisposition. Interestingly, even twins differ in many ways.
What is the function of the genetic code?
It contains information about a person’s predispositions and characteristics. This means that it can be used to determine, for example, external appearance, voice color, height and character, and other features, such as eye color, hair color, and face shape. Nevertheless, many of these characteristics change as a person grows – for example, siblings brought up in the same home may have completely different interests.
An important issue related to the genetic code is the process of inheritance. New threads of genetic information are created during cell division as a result of replication. If an error occurs during the process, the consequences can be dangerous for the body. The genetic code includes, for example, a tendency to develop diseases – when we know that our relatives have suffered from a given disease, we can go to a geneticist and determine the likelihood of developing the same ailment.
What is genetic testing and what is it for?
A saliva or blood sample is needed to perform a genetic test. Usually, most genetic tests are performed with saliva, but in exceptional circumstances venous blood may be required. Saliva is the most readily available biological fluid and contains a lot of genetic information that can be used for diagnosis.
Genetic testing makes it possible to identify genetic disorders. Thanks to the test, you can determine why certain symptoms are occurring, quickly make a diagnosis and start treatment – including useful in the diagnosis of the causes of infertility in women and men.
Prognostic genetic tests are used to detect changes and polymorphisms in the patient’s genetic material. Their presence suggests that the development of one of the diseases, so healthy people or those in whom symptoms have not yet appeared are often taken in the study. The advantage of the tests is the possibility of determining the lifetime risk of, for example, cancer. In addition, the patient becomes aware of his inclinations and thus can go to a specialist and start preventive measures.
The advantage of performing a genetic test with saliva is that it does not cause pain and is non-invasive – the patient feels more comfortable and the doctor receives high-quality DNA. The saliva test is not stressful, which is especially important when the patient is a child. What’s more, the entire test can also be performed remotely – the test person can send the sample to the laboratory with the help of a courier.
Learn about the 8 most popular genetic diseases
- Huntington’s disease is an inherited neurodegenerative disease, which occurs at a frequency of 1,63 – 9,95 per 100 people in Europe. The inhabitants of other continents suffer from it much less frequently. The first symptoms most often appear in the 000th and 4th decade of life, and its adolescent form, the so-called the Westphal variant appears in people under the age of 5. Symptoms include chorea, less muscle tone, tremors, dysphagia, and dysarthria
- Down syndrome – the disease occurs with a frequency of 1: 800 to 1000 live births. It is a group of genetic defects, the symptoms of which are short stature, a small head, flattened in the occipital part, and a round, flat face. Patients also have deformed ears and mild, moderate or severe intellectual disability. However, people with Down’s syndrome are talkative and willing to engage in social interactions.
- Cystic fibrosis – The incidence of the disease in Europe is on average 1: 2 in 500 live born babies. Its main symptoms are malfunctions in the functioning of the respiratory and digestive systems. In Poland, newborns are tested for the presence of the disease. People suffering from it live about 40 years, but in highly developed countries about 50 years.
- Klinefelter’s syndrome is an inherited disease that occurs in men who have an extra X chromosome in their genetic material in all or some parts of the body’s cells. Affected men after puberty are tall, with underdeveloped muscles, small testicles, pale skin, sparse hair, and decreased libido. Many of them also have difficulty expressing their thoughts and needs, but are nevertheless able to work and function in society.
- Edwards syndrome – the incidence is approximately 1: 8000 births. It is caused by an abnormal structure of the genetic material containing the third chromosome 18. The symptoms of the disease include: low birth weight, microcephaly, protruding occipital bone, cleft lip, defects of the respiratory system and urinary system. It is not a hereditary disease.
- Turner syndrome – is a disease of girls, affecting 1 in 2000-2500 babies born. The reason is, among others the complete or partial absence of one of the X chromosomes in all or some of the cells in the body. One of the symptoms of the disease is the presence of an additional skin fold in the nape area – this is a condition that occurs in approximately 30% of girls. Other symptoms include short stature, abnormal shape of the reproductive organs and cardiovascular defects.
- Williams syndrome – the disease affects 1 in 10-20 thousand. births. It is caused by the loss of 26 to 28 genes within one of the chromosome pair 7. It is usually not hereditary. Its symptoms are the so-called elven beauty – the patient has fleshy lips, a wide forehead and auricles similar to elven turbinates. Sick people also suffer from mild mental disabilities and often have difficulty speaking.
- Muscular dystrophy – occurs in 1 in 3500 boys births, and in most cases they are the only boys. It is an inherited disease caused by a mutation in the DMD gene that causes dystrophin – the disease is passed on by mothers. The symptom is muscle wasting, which becomes weaker. The child cannot walk, has problems with balance, has shorter joints, spinal scoliosis, deformed calves and cardiac arrhythmias.