Glossary

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Gene: The basic unit of heredity, a gene is a segment of DNA containing the information a cell needs to make (or “encode”) proteins or perform a regulatory function. Humans have about 25,000 protein-coding genes.

Gene expression: Genes turn on and off (or more accurately, up and down) by producing more or less RNA. Since genes encode proteins, an alteration in gene expression can lead to disease, such as when the wrong protein, or too much or too little of the right protein, is made in a particular cell.

Gene mutation: A change in a DNA sequence that changes the DNA code and so might result in disease. Mutations can be caused by many factors, including exposure to mutagens in tobacco smoke.

Gene regulation: The 25,000 or so genes in the cell encode proteins, not all of which are required by each and every cell at all times. Gene regulation is how cells control which genes are active in each cell.

Gene variant: Gene sequences vary among individuals. A gene variant, determined by its DNA sequence, is the specific form of a gene that a person carries. For example, the major blood types, A, B, and O, are determined through the gene variants a person carries for the ABO gene.

Genetics: The branch of biology that studies heredity and variation in living organisms; the science of identifying the genes responsible for particular traits (such as risk for disease).

Genome: Refers to all the biological information—all the genes—encoded in an organism’s DNA and required for life. See also, human genome.

Genomic analysis: The use of techniques such as genome sequencing, genome-wide association studies, gene expression analysis, epigenetic analysis, together with bioinformatics, to understand the how changes in the DNA sequence, its structure, or how genes are expressed can be linked to disease. See also, Research Methods under "What We Do."

Genomic data: The information that comes out of genomic studies.

Genomic medicine: An emerging practice of medicine that involves using genomic data to better predict, diagnose, and treat disease.

Genomic science: See also, genomics.

Genomics: The branch of biology that involves the simultaneous study of large numbers of genes, or all the genes, in an organism.

Genotype: An organism’s unique genetic blueprint as contained in its DNA and inherited from previous generations.