Basic Components of Human Genetics INTRODUCTION
What is Genetics? • Genetics – • It is the branch of biological sciences which deals with the transmission of characters from parents to offspring. • The term genetics was coined by Bateson in 1906. It has been derived from the Greek word ‘gene’. • (gene= ‘to become’) • Genes – • set of characteristics inherited from your parents • Found on chromosomes and contain DNA
Heredity • The transfer of character or traits from the parents to offspring.
Variations • The similarities and differences between the character or traits among the individuals of the same species.
IMPLICATIONS OF GENETICS TO HUMAN WELL-BEING • Knowledge of genetics is helpful in understanding the causation of diseases. • It also helps us to understand how normal variation between individuals are brought about. • Knowledge of genetics has also led to possible means of prevention of genetic disorders through genetic counseling and antenatal diagnosis. • Genetics serves to solve even legal problems. Legal cases involving disputed parentage may be sorted out by an analysis of blood groups or other inherited characteristics.
Genetics in relation to other sciences Cytogenetics Biochemical Radiation Genetics Eugenetics Developmental Clinical Physiological Immunogenetics
1. Cytogenetics • A branch of genetics that is concerned with the study of the structure and function of the cell, especially the chromosomes. • This discipline is concerned with the cytologic and molecular bases of genetics. • Example: Down syndrome (trisomy 21) • Patau Syndrome (trisomy 13) • Edward Syndrome (trisomy 18) • Chronic Myelogenous Leukemia (has a small chromosomes in WBC)
2. Biochemical Genetics • the study of fundamental relationships between genes, protein, and metabolism. • This involves the study of the cause of many heritable diseases. • Example: • SICKLE CELL ANEMIA and THALASSEMIA • PHENYLKETONURIA and GALACTOSEMIA
3. Developmental Genetics • The branch of science of development which attempts to understand the role of genes in development. • the process that gives rise to tissues, organs and anatomy. • It is a process which brings about various changes in fertilized egg to make it into a complete adult.
4. Physiological Genetics - This branch of genetics involves the use of knowledge of physiology to elucidate the effects produced by genetic factors on an individual. - relationship of hereditary diseases and genetics
5. Immunogenetics - It is a branch of science which is concerned with the genetic aspects of immunity mechanisms.
6. Clinical Genetics - It is a branch of genetics which helps to establish the causative factors responsible for certain disease like Diabetes Mellitus, Haemophilia etc.
7. Radiation Genetics - This branch of genetics involves the study of effects of various radiation on genes.
8. Eugenics- “eu” means “good/well”genes means born - It is a branch of science which deals with the application of principles of heredity to the improvement of mankind. - Francis Galton defined eugenics as the study of all agencies under human control which can improve or impair the racial quality of future generations.
2 Categories of Eugenics 1. Positive Eugenics • Aimed at encouraging reproduction among the genetically advantaged • Example: the reproduction of the intelligent, the healthy and the successful • Approaches: • Financial and political stimuli • Targeted demographic analysis • In vitrofertilization • Egg transplants • cloning
2. Negative Eugenics • Aimed to eliminate through sterilization or segregation • Physically, mentally or morally undesirable • Approaches: • Abortions • Sterilization • Or other methods of family planning
Human Genome Project The Human Genome Project formally began in 1990 and was completed in 2003
What is Human Genome Project? • Is an international scientific research project • The Project was coordinated by the National Institutes of Health and the U.S. Department of Energy. • Additional contributors included universities across the United States and international partners in the United Kingdom, France, Germany, Japan, and China.
It is a collaborative venture to identify and mark all the locations of every genome of the human species. • In US, the HGP was started at 1990 and was expected to be a fifteen year effort to map the human genome. • 2003 the project accelerated its progress • Hopes to discover 50,000- 100,000 human genes and make them available for further biologic study.
Goals of Human Genome Project • Determine the entire sequence of human DNA (3,000,000,000 bases in the haploid human genome) • Identify all the genes in human DNA approximately 35,000 genes. • Store this information in databases • Improve tools for data analysis • Transfer related technologies to the private sector • Address the ethical, legal, and social issues (ELSI) that may arise from the project.
What is DNA sequencing? • Sequencing means determining the exact order of the base pairs in a segment of DNA. • Map-based (gene mapping) or BAC- based (bacterial-artificial chromosome)- is a method used by the HGP to produce the finished version of the human genetic code
Benefits of HGP 1. In the field of molecular medicine • Better diagnosis of disease, • Early detection of certain diseases • Gene therapy and control systems of drugs • In the future there should be new treatments in molecular medicine that don’t treat the symptoms but look at the causes of the problem at hand.
Benefits of HGP 2. In the field of microbial genomics • They may be able to find new energy sources, through the sequencing of a bacterial genome. • This could lead to discoveries that are useful in energy production, toxic waste reduction, and industrial processing.
Benefits of HGP 3.Can be very useful for the understanding of human evolution and human migration. - it may help lead scientists to find out how humans evolved and how humans are evolving today. 4. It will help to understand the common biology that we share with life on earth. Comparing our genome with others may help to lead to associations of diseases with certain traits.
Benefits of HGP 5. In the field of agriculture and livestock breeding - this technology could help to develop disease, insect, and drought resistant crops thus being able to produce more for the world. - it also help to produce healthier, more productive, and possibly disease resistant animals to be sent to market.
Disadvantages of Human Genome Project • Research cost is high • People are afraid of discrimination of genes • People don’t support gene therapy because it’s “against nature”
Ethical, Legal, and Social Issues • Fairness in the use of genetic information by insurers, employers, courts, schools, adoption agencies, and the military, among others. • Psychological impact, stigmatization, and discrimination based on genetic differences/ disorders. • Privacy and confidentiality of genetic information • Reproductive issues including adequate and informed consent and use of genetic information in reproductive decision making • Clinical issues including the education of doctors and other health-service providers, people identified with genetic conditions, and the general public about capabilities, limitations, and social risks; and implementation of standards and quality-control measures.
PREDICTIONS FOR THE NEXT TEN YEARS • Science Will Pinpoint What Makes Us Homo Sapiens In the near future, scientists will be able to compare our genome against those of our evolutionary cousins, such as chimpanzees and Neanderthals, to get a clearer sense of which genes are involved in making us Homo sapiens
2. Gene Therapy will cure diseases Gene therapy—curing ailments by replacing faulty copies of genes with normal ones—will finally become a reality, likely within the next decade.
3. Personal Genomes Will Spawn Made-to-Measure Drugs • Thanks to improving technology, within the next five years a person should be able to have his or her entire genome sequenced for about a thousand U.S. dollars, many experts say.
4. Personality Will Move From Art to Science • As scientists learn to better understand the information contained in our genomes, they will get better at predicting how genes influence the development of physical and mental traits and even behaviors.
Take detailed family history • Construct Pedigrees
Assess hereditary and non hereditary risk factors related to genetic diseases, or diseases with a genetic component • Provide genetic information to individuals and families
Interpret genetic tests and laboratory data • Manage and care for patients and families at risk for or affected by genetic diseases or diseases with a genetic component.
Provide genetic counseling, genetic consultation, and case management for persons with complex genetic health care needs.