What is genetics? What is genomics?
Genetics is the study of inheritance, how personal traits, such as eye and hair color, are passed from one generation to the next through genes. Genes contain the instructions for making specific proteins, which direct cell functions. Genomics is the total set of genes in an individual, and it is the study of a person’s network of genes, how they interact with each other and with that person’s environment.
What is genomic medicine?
Genomic medicine is the use of genotypic analysis (DNA testing) to enhance the quality of medical care, including presymptomatic identification of susceptibility to disease, preventive intervention, selection of pharmocotherapy, and individual design of medical care based on genotype.
What is DNA?
DNA is the double-stranded molecule that encodes genetic information in the nucleus of cells. A DNA strand is composed of four different nucleotides or base pairs (adenine, guanine, cytosine, and thymidine). It determines the structure, function and behavior of the cell. In animals and plants, long strands of DNA are arranged into structures called chromosomes.
Genes are sometimes known as the physical unit of heredity. Genes are formed from DNA, carried on the chromosomes and are responsible for the inherited characteristics that distinguish one individual from another. Each human individual has an estimated 30,000 separate genes.
Chromosomes are the self-replicating genetic structures of cells. They contain the cellular DNA that bears in its nucleotide sequence the linear array of genes.
RNA is the single-stranded molecule that is transcribed from DNA and ultimately translated into a chain of amino acids that form a protein.
Proteins are the principal constituents of the protoplasm of all cells. Each protein has a unique, genetically defined amino acid sequence that determines its specific shape and function. Proteomics is the study of proteins and how they work.
How do genes work?
While each cell contains a full complement of DNA, a normal cell activates just the genes it needs at the moment and actively suppresses the rest. Some genes enable cells to make proteins needed for basic functions, some play a role in early development of the embryo and are then shut down forever, and many encode proteins that are unique to a particular kind of cell and that give the cell its character - making a brain cell, say, different from a bone cell.
How are genes linked to disease?
Many diseases have their roots in genes. Genes determine everything from how efficiently we process foods to how vigorously we respond to infections. More than 4,000 diseases are thought to stem from mutated genes inherited from at least one parent. Common disorders such as heart disease and most cancers arise from a complex interplay between multiple interacting genes (genetic susceptibility) and environmental factors. Individual susceptibility to these common disorders is often associated with prevalent DNA variations in the human genome (polymorphisms).
What is genetic testing?
Genetic testing is a type of laboratory test that looks for changes in a person’s genetic material (DNA, genes or chromosomes) or in the products that the genes make. Most times genetic testing is done by taking a blood sample, but sometimes other body samples (like cheek cells or skin) are needed.
There are many genetic conditions for which no testing is available. If testing is available and is done, results are usually given in person during a second genetic counseling session. Anyone who has unanswered questions about disorders or traits that run in their family could benefit from genetic testing and counseling.