Apoptosis
Apoptosis signifies a process in which certain signals lead cells to self-destruct. This is one way by which the organism protects itself against cells which have taken the first step in the transformation into cancer cells. Cancer cells, on the other hand, often carry mutations that make them resistant to this form of cell death.

Bioinformation technology
A method involving comparison of genetic information obtained in the form of sequences by computing methods. Bioinformation technology particularly allows comparison of genomes of different species and the detection of biological processes preserved during the course of evolution.

Biotechnology
A term designating the use of genetic engineering for practical purposes, notably the production of proteins in living organisms or some of their components (bacteria, mammalian cells).

Cell
The fundamental unit of all living things. Some organisms are formed only of one cell, such as bacteria and protozoa. Most plants and animals are formed from several million cells of various types, each specializing in a particular function.

Chromosomes
The organized structure that carries the genetic information, often appearing as rods in the nucleus. All the cells of an individual of a given species contain the same number of chromosomes. Humans have 46 chromosomes, half of which come from the father and the other half from the mother.

Cloning
The isolation and artificial multiplication of DNA. The repeated multiplication or reproduction of genetically identical cells or organisms.

DNA (Deoxyribonucleic acid)
A macromolecule containing the bases adenine, thymine, cytosine and guanine, the sugar deoxyribose and phosphate groups. By means of the sequence of bases along its strands, DNA codes the genetic information in all living organisms.

Electrophoresis
The separation in an electrical field of the macromolecular constituents in a mixture (proteins, nucleic acids).

Gene therapy
A therapeutic strategy aimed at introducing genes into an organism for the purpose of correcting genetic defects.

Gene
DNA segment which, due to its individual composition of pairs of bases, is responsible for the production of specific proteins. Genes are the basic units of heredity. The order in which the 4 bases of DNA are linked in a gene is called the sequence of a gene.

Genetic engineering
The use of molecular biology tools for the deliberate modification of DNA, with the consequence of modifying the nature and expression of genes for the purpose of understanding their function.

Genome (or genetic make-up)
All the genetic information of an individual. genome.

Molecular biology
A science covering the study of phenomena occurring inside cells, particularly the chemical structure and expression of genetic information.

Mutation
A random or induced event that can lead to an inheritable modification of the genome.

Nucleus
It contains the chromosomes that carry the genetic information (DNA) of a cell.

Oncogene
A gene coding for a protein that can contribute to the transformation of a normal cell into a tumor cell.

PCR (Polymerase Chain Reaction)
A process allowing the multiplication and detection of minute traces of DNA.

Protein
A macromolecule formed from a sequence of amino acids synthesized according to the genetic information coded by RNA (translation). Proteins are the fundamental functional and structural constituents of cells.

Restriction enzymes
Biological scissors (enzymes) that recognize and cut a specific DNA sequence.

Sequencing
The determination of genetic information coded in the form of its basic building blocks (nucleotides: G, A, T, C). All the human genetic information will be sequenced within a few years from now.

Transgenesis
The introduction of foreign genes into an organism to confer new properties on that organism. This method is generally used to study the function of genes in the context of a living organism.