Genetics and health: how heredity affects our well -being

Genetics and health: how heredity affects our well -being

I. Fundamentals of human genetics: the key to understanding heredity

1. Human genome: a complete set of instructions

   • Definition genome: The human genome is a complete set of genetic information encoded in DNA. It includes all genes, as well as non -dodging areas of DNA, which play an important role in the regulation of genes activity.
   • DNA structure: DNA consists of two complementary circuits forming a double spiral. Each chain consists of nucleotides containing a nitrogen base (adenin, guanine, cytosine or thyamin), deoxybosis sugar and phosphate group. Adenin (a) is always connected to Timin (t), and guanine (G) with cytosin (C).
   • Chromosomes: DNA packaging: The human genome is divided into 23 pairs of chromosomes located in the nucleus of each cell. One chromosome from each pair is inherited from the mother, and the other from the father. Chromosomes consist of DNA, tightly rolled around proteins called histones.
   • Genes: units of heredity: Genes are DNA areas containing instructions for protein synthesis. Proteins perform a variety of functions in the body, from structural to regulatory.
   • Non -dodging DNA: Most of the human genome (about 98%) consists of non -dodging DNA. It was previously believed that this DNA has no function, but now it is known that it plays an important role in the regulation of genes activity, maintaining the structure of chromosomes and other processes.

2. Genes inheritance: transmission of genetic information

   • Mendelevskoye inheritance: The basic principles of inheritance were formulated by Gregor Mendel in the 19th century. He found that the signs are inherited discretely through genes, and that each organism receives one copy of the gene from each parent.
   • Alleles: Genes options: Alleles are various options for the same gene. For example, the gene responsible for eye color can have alleles for brown, blue or green eyes.
   • Dominant and recessive alleles: The dominant allele is manifested in the phenotype (external signs) even in the presence of only one copy, while the recessive allele manifests itself only in the presence of two copies.
   • Genotype and phenotype: The genotype is the genetic constitution of the body, that is, a set of alleles that it carries. The phenotype is the observed characteristics of the body, which are the result of the interaction of the genotype and the environment.
   • Mendel’s laws:
     • The law of the uniformity of the first generation hybrids: When crossing two homozygous organisms (having the same alleles), all descendants of the first generation will be heterozygous (having different alleles) and will have the same phenotype due to the dominant allele.
     • The law of splitting signs: When crossing two heterozygous organisms in the second generation, there is a splitting of signs in a certain ratio (usually 3: 1 for dominant and recessive features).
     • Independent inheritance law: Genes located on different chromosomes or far from each other on one chromosome are inherited independently of each other.

3. Mutations: changes in the genetic code

   • Determination of mutations: Mutations are changes in the DNA sequence. They can occur spontaneously or be caused by the influence of mutagenes (chemicals, radiation, etc.).
   • Types of mutations:
     • Particular mutations: Changes in one nucleotide.
       • Replacements: Replacement of a number of nucleotide others.
       • Inserts: Insert one or more nucleotides.
       • Deletions: Removing one or more nucleotides.
     • Chromosomal mutations: Changes in the structure or quantity of chromosomes.
       • Deletions: Removing the chromosome site.
       • Duplications: Doubling the site of the chromosome.
       • Inversions: The coup of the chromosome site is 180 degrees.
       • Translocations: Moving the chromosome section to another chromosome.
       • Aneuploidii: Changing the number of chromosomes (for example, trisomy, when there are three copies of chromosome instead of two).
   • The influence of mutations: Mutations can be neutral, useful or harmful. Harmful mutations can lead to the development of genetic diseases.
   • Mutations in germ and somatic cells: Mutations in the germ cells are transmitted to offspring, while mutations in somatic cells are not transmitted, but can lead to the development of diseases such as cancer.

4. Epigenetics: heredity without changing DNA

   • Determination of epigenetics: Epigenetics is a study of changes in the expression of genes (genes’ activity), which are not associated with changes in the sequence of DNA.
   • Epigenetic mechanisms:
     • DNA methylation: Connection of a methyl group to cytosin in DNA. Methyling usually leads to suppression of genes expression.
     • Modification of histones: Changes in the structure of histones around which DNA is wrapped. Histonian modifications can activate or suppress the expression of genes.
     • Non -pounding RNA: Non -leading RNAs (for example, micrord) can regulate the expression of genes, contacting MRNA and blocking its broadcast into protein.
   • The influence of epigenetics on health: Epigenetic changes can affect the development of various diseases, including cancer, cardiovascular diseases and neurodegenerative diseases.
   • Inheritance of epigenetic changes: Epigenetic changes can be inherited during several generations, which means that the experience of ancestors can affect the health of descendants. Environmental factors, such as nutrition, stress and the effects of toxins, can cause epigenetic changes that are inherited.

II. Hereditary diseases: when genes become a problem

1. Classification of hereditary diseases

   • Monogenic diseases: Caused by a mutation in one gene.
     • Autosomal dominant: The disease is manifested in the presence of at least one copy of the mutant gene (for example, the disease of the hydroxide).
     • Autosomal recessive: The disease manifests itself only in the presence of two copies of the mutant gene (for example, cystic fibrosis, phenylketonuria).
     • Linked to the floor (X-linked): The mutant gene is located on the X-chromosome. In men with only one X-chromosome, the disease manifests itself in the presence of one copy of the mutant gene (for example, hemophilia, Dyushenna dystrophy). In women, the disease manifests itself only in the presence of two copies of the mutant gene (in the case of recessive inheritance).
     • Y-linked: The mutant gene is located on the Y chromosome. The disease is transmitted only from father to son.
   • Chromosomal diseases: Caused by a change in the number or structure of chromosomes (for example, Down syndrome, Turner syndrome).
   • Mitochondrial diseases: Caused by mutations in mitochondrial DNA. Mitochondria is transmitted along the maternal line.
   • Multifactorial diseases: Caused by the interaction of genetic factors and environmental factors (for example, type 2 diabetes, cardiovascular diseases, cancer).

2. Examples of common monogenic diseases

   • Cystic fibrosis (cystic fibrosis): An autosomal recessive disease caused by a mutation in the CFTR gene, which encodes a protein that regulates the transport of chloride through cell membranes. This leads to the formation of thick mucus in the lungs, pancreas and other organs, which causes problems with breathing, digestion and reproductive function.
   • Phenylketonuria (FCU): An autosomal recessive disease caused by a mutation in the PAH gene, which encodes the enzyme phenylalain nyxilosis. This enzyme is necessary for the splitting of phenylalanine, amino acids coming from food. The accumulation of phenylalanine in the blood can lead to damage to the brain and mental retardation.
   • Gentington disease: Autosomas and dominant disease caused by a mutation in the HTT gene, which encodes the Hunting protein. The mutation leads to the formation of an abnormal protein, which accumulates in the cells of the brain and causes their degeneration. The disease is manifested in adulthood and is characterized by involuntary movements, cognitive impairment and mental disorders.
   • Sickle -cell anemia: An autosomal recessive disease caused by a mutation in the HBB gene, which encodes beta-globin, a hemoglobin component. The mutation leads to the formation of abnormal hemoglobin, which deforms red blood cells, giving them a sickle form. Cherpate red blood cells do not tolerate oxygen and can clog blood vessels, causing pain, organs damage and other complications.
   • Hemophilia: A X-linked recessive disease characterized by a impaired blood coagulation. It is caused by mutations in genes encoding blood coagulation factors (usually factor VIII or factor IX).

3. Chromosomal abnormalities and their consequences

   • Down Syndrome (Trisomy 21): It is caused by the presence of three copies of the 21st chromosome instead of two. It is characterized by mental retardation, characteristic features of the face, heart defects and other health problems.
   • Turner syndrome (monosomy x): It is caused by the absence of one of the X-chromosomes in women. It is characterized by low growth, ovarian underdevelopment, infertility and other health problems.
   • Klainfelter syndrome (XXY): It is caused by the presence of an additional X-chromosome in men. It is characterized by high growth, underdevelopment of testicles, infertility and other health problems.

4. Genetic predisposition to multifactorial diseases

   • Cardiovascular diseases: Genetic factors play an important role in the development of cardiovascular diseases, such as coronary heart disease, stroke and hypertension. Certain genes can increase the risk of developing these diseases, but environmental factors, such as diet, smoking and physical activity, also play an important role.
   • Type 2 diabetes: Genetic predisposition plays an important role in the development of type 2 diabetes. Certain genes can increase the risk of insulin resistance and insulin secretion disorders. However, environmental factors, such as obesity and sedentary lifestyle, also play an important role.
   • Cancer: Genetic factors can increase the risk of various types of cancer. For example, mutations in the BRCA1 and BRCA2 genes increase the risk of breast cancer and ovarian cancer. However, environmental factors, such as smoking, diet and exposure to carcinogens, also play an important role.
   • Autoimmune diseases: Genetic factors play an important role in the development of autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis and Crohn’s disease. Certain genes can increase the risk of developing these diseases, but environmental factors, such as infections and stress, also play an important role.
   • Mental disorders: Genetic factors play an important role in the development of mental disorders, such as schizophrenia, bipolar disorder and depression. Certain genes can increase the risk of developing these disorders, but environmental factors, such as stress and injuries, also play an important role.

III. Genetic testing and counseling: tools for evaluating and managing risk

1. Types of genetic tests

   • Diagnostic testing: It is used to confirm or exclude the diagnosis of a genetic disease in a person with symptoms.
   • Presumptomatic testing: It is used to detect genetic mutations that can cause the disease in the future, before the onset of symptoms (for example, hydroelectington disease).
   • Predictive testing: It is used to assess the risk of developing the disease in the future (for example, breast cancer in the presence of mutations in the BRCA1 and BRCA2 genes).
   • Screening of carriage: It is used to identify carriers of recessive mutations that can convey these mutations to their children.
   • The prenatal diagnostics: It is used to detect genetic abnormalities in the fetus during pregnancy (for example, amniocentesis, choriona biopsy).
   • Preimplantation genetic diagnostics (PGD): It is used to detect genetic anomalies in embryos created using extrakorporporic fertilization (IVF), before their implantation into the uterus.
   • Pharmacogenetic testing: It is used to determine genetic options that can affect a person’s reaction to certain drugs.
   • Full -seed sequencing (WGS): Determines the sequence of the entire human genome.
   • Full Exvenitation (WES): Determines the sequence of only exons, sections of genes, encoding proteins.
   • Targetic sequencing: Determines the sequence of specific genes or genes.

2. The process of genetic testing

   • Consultation with a geneticist: Before conducting genetic testing, it is recommended to consult a geneticist who will explain the goals and restrictions on testing, interpret the results and provide recommendations for risk management.
   • Sample collection: To conduct genetic testing, a sample of blood, saliva or tissue is usually required.
   • DNA analysis: A DNA sample is analyzed in the laboratory to identify genetic mutations or anomalies.
   • Interpretation of the results: The results of genetic testing are interpreted by a geneticist taking into account the medical history of man and family history.
   • Providing results and counseling: The results of genetic testing are provided to a person and are discussed with a geneticist. The geneticist provides recommendations for risk management, treatment and prevention of diseases.

3. Ethical and social aspects of genetic testing

   • Confidentiality: The results of genetic testing should be confidential and should not be transferred to third parties without human consent.
   • Discrimination: There is a risk of discrimination based on genetic information by employers, insurance companies and other organizations.
   • Psychological impact: The results of genetic testing can have a significant psychological effect on a person and his family.
   • Reproductive solutions: The results of genetic testing can affect the reproductive solutions of a person, such as family planning, the use of prenatal diagnostics or PGD.
   • Accessibility: Genetic testing should be available to everyone who needs it, regardless of their socio-economic status.
   • Informed consent: A person must receive complete information about the goals, risks and advantages of genetic testing and give informed consent to its conduct.

4. Genetic counseling: Assistance in decision -making

   • Genetic counseling goals:
     • Providing information about genetic diseases and risks of their development.
     • Interpretation of genetic testing results.
     • Assistance in making reproductive decisions.
     • Providing emotional support.
     • Help in risk management and disease prevention.
   • Genetic counseling process:
     • Collection of medical history and family history.
     • Discussion of the goals and restrictions of genetic testing.
     • Interpretation of genetic testing results.
     • Discussion of treatment and prevention of diseases.
     • Providing information about resources and support.

IV. The effect of heredity on specific aspects of health

1. Heredity and mental health

   • Schizophrenia: Genetic factors play an important role in the development of schizophrenia. The risk of schizophrenia is increasing if a person has relatives suffering from this disease.
   • Bipolar disorder: Genetic factors also play an important role in the development of bipolar disorder. The risk of developing bipolar disorder increases if a person has relatives suffering from this disease.
   • Depression: Genetic factors can increase the risk of depression, but environmental factors, such as stress and injuries, also play an important role.
   • Alarm disorders: Genetic factors can increase the risk of anxiety disorders, such as generalized alarming disorder, panic disorder and social alarm.
   • Autism: Genetic factors play an important role in the development of autism. Many genes were associated with an increased risk of autism.
   • ADHD (attention deficit syndrome and hyperactivity): Genetic factors also play an important role in the development of ADHD.

2. Heredity and cardiovascular system

   • Hypertension (high blood pressure): Genetic factors can increase the risk of hypertension.
   • Corny heart (coronary heart disease): Genetic factors play an important role in the development of coronary heart disease. Certain genes can affect the level of cholesterol, blood coagulation and other factors that increase the risk of IBS.
   • Stroke: Genetic factors can increase the risk of stroke.
   • Cardiomyopathy: Cardiomyopathy is a disease in which the heart muscle becomes thick, thin or rigid. Genetic factors play an important role in the development of cardiomyopathy.
   • Congenital heart defects: Congenital heart defects are structural anomalies of the heart that are present at birth. Genetic factors can play a role in the development of some congenital heart defects.

3. Heredity and immune system

   • Autoimmune diseases: Genetic factors play an important role in the development of autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, Crohn’s disease and systemic lupus erythematosus. Certain genes can increase the risk of developing these diseases.
   • Immunodeficiency: Immunodeficiences are conditions in which the immune system does not function properly. Genetic factors can play a role in the development of some immunodeficiency.
   • Allergies: Genetic factors can increase the risk of developing allergies, such as pollen allergies, food allergies and allergies to drugs.

4. Heredity and endocrine system

   • Type 1 diabetes: Genetic factors play an important role in the development of type 1 diabetes.
   • Type 2 diabetes: Genetic factors also play an important role in the development of type 2 diabetes.
   • Thyroid diseases: Genetic factors can increase the risk of thyroid diseases, such as hypothyroidism (lack of thyroid hormones) and hyperthyroidism (excess hormones of the thyroid gland).
   • Polycystic ovary syndrome (PCU): Genetic factors can play a role in the development of PCU.

5. Heredity and cancer

   • Breast cancer: Mutations in the BRCA1 and BRCA2 genes significantly increase the risk of breast cancer and ovarian cancer.
   • Ovary cancer: Mutations in the BRCA1 and BRCA2 genes also increase the risk of ovarian cancer.
   • Tolstoy Cancer: Genetic factors can play a role in the development of colon cancer. Lynch syndrome is a hereditary disease that significantly increases the risk of developing colon cancer.
   • Prostate cancer: Genetic factors can increase the risk of prostate cancer.
   • Melanoma: Genetic factors can play a role in the development of melanoma.

V. Life and genetics: interaction and influence

1. Diet and genes: how nutrition affects the expression of genes

   • Nutrigenomy: Studies the effect of nutrients on the expression of genes.
   • The influence of the diet on epigenetic changes: Diet can cause epigenetic changes that affect the expression of genes and the risk of developing diseases.
   • Personalized diet: Genetic testing can help develop a personalized diet taking into account the genetic characteristics of a person.
   • Examples:
     • In people with a genetic predisposition to lactose intolerance, it is recommended to avoid the use of dairy products.
     • In people with a genetic predisposition to cardiovascular diseases, it is recommended to use a low content of saturated fats and cholesterol.
     • In people with a genetic predisposition to type 2 diabetes, it is recommended to use a diet with a low glycemic index.

2. Physical activity and genes: how exercises modulate a genetic predisposition

   • The influence of physical activity on the expression of genes: Physical activity can change the expression of genes associated with metabolism, immunity and health of the cardiovascular system.
   • Genetic factors and sports achievements: Genetic factors can affect the sports achievements of a person.
   • Personalized training: Genetic testing can help develop a personalized training program taking into account the genetic characteristics of a person.
   • Examples:
     • In people with a genetic predisposition to a slow set of muscle mass, it is recommended to engage in strength training.
     • In people with a genetic predisposition to high endurance, it is recommended to engage in aerobic training.

3. Stress and genes: how chronic stress affects heredity

   • The effect of stress on epigenetic changes: Chronic stress can cause epigenetic changes that affect the expression of genes and the risk of developing mental and physical diseases.
   • Genetic factors and sensitivity to stress: Genetic factors can affect human sensitivity to stress.
   • Stress management strategies: Strategies for stress management, such as meditation, yoga and physical activity, can help reduce the negative impact of stress on genetic predisposition.

4. Smoking, alcohol and genes: the interaction of bad habits and heredity

   • The effect of smoking and alcohol on epigenetic changes: Smoking and alcohol consumption can cause epigenetic changes that affect the expression of genes and the risk of cancer, cardiovascular diseases and other diseases.
   • Genetic factors and a predisposition to addictions: Genetic factors can affect a person’s predisposition to addictions such as nicotine and alcohol dependence.
   • Avoiding bad habits: Avoiding smoking and alcohol consumption can reduce the risk of developing diseases associated with genetic predisposition.

VI. Future of genetics and health: prospects and challenges

1. Development of genomic technologies: new opportunities for diagnosis and treatment

   • CRIPR-CAS9 (CRISPR-CAS9): Genoma editing technology that allows you to accurately change the DNA sequence.
   • Genotherapy: The treatment method, which consists in introducing genetic material into human cells for the treatment or prevention of diseases.
   • Liquid biopsy: The diagnostic method that allows you to identify genetic abnormalities in the blood or other body fluids.
   • Artificial intelligence (AI) in genetics: AI can be used to analyze large volumes of genetic data and identify new laws.

2. Personalized medicine: treatment based on a genetic profile

   • Pharmacogenomy: Studies the effect of genetic factors on a person’s reaction to drugs.
   • Personalized prevention: Development of diseases prevention programs that take into account the genetic characteristics of a person.
   • Target therapy: The development of drugs that affect specific genetic mutations that cause diseases.

3. Ethical and social challenges of the genomic era

   • Confidentiality of genetic information: Protection of genetic information from unauthorized access and use.
   • Equality of access to genomic technologies: Ensuring equal access to genomic technologies for all, regardless of their socio-economic status.
   • Genome editing regulation: Development of ethical and legal norms governing the use of genome editing technology.
   • Public understanding of genetics: Improving the level of knowledge about genetics in the population and a decrease in genetic illiteracy.

4. Integration of genetics into the healthcare system

   • Training of medical workers: Education of medical workers with the basics of genetics and genomic technologies.
   • Creation of genetic centers: Creation of specialized genetic centers providing genetic testing and counseling services.
   • Development of clinical recommendations: Development of clinical recommendations for the use of genetic testing in various fields of medicine.
   • Financing of genetic research: Increasing financing of genetic research to develop new methods of diagnosis and treatment of diseases.