Non-exhaustive list of definitions of technical terms used in gerontology and in senescence.info. Considered work-in-progress.
Aging: a progressive deterioration of physiological function, an intrinsic age-related process of loss of viability and increase in vulnerability. In humans aging is characterized by a complex phenotype.
Allele: an alternative form of a gene.
Aphagy: inability to feed oneself due to anatomical deficiencies, common in the adult phase of some species of animals.
Apoptosis: programmed cell death.
Antagonistic pleiotropy: theory by George Williams that explains the existence of aging by the existence of genes beneficial early in life but harmful at later stages.
Autophagy: digestion of the cell's organelles.
Caloric restriction (CR): diet regime consisting of eating fewer calories that has been considered as a potential method to delay aging.
Cellular, clonal, or replicative senescence: cessation of cell division, usually determined in a cell population, that can or not be accompanied by cell death.
Cellular immortality: the ability of certain cellular populations to divide indefinitely in culture.
Demography: the statistical study of human populations.
Developmental theory of aging (DevAge): theory that argues aging is an extension of developmental mechanisms.
Diphyodont: an animal that develops two successive sets of teeth, common in most mammals.
Diploid: a cell with two sets of chromosomes.
Dyskeratosis congenita: genetic disease caused by defects in the dyskerin protein, one of the components of telomerase.
Disposable soma theory: theory by Thomas Kirkwood that explains the existence of aging by the allocation of resources from somatic maintenance to reproduction.
Ectotherm: a cold-blooded animal, such as a reptile, fish, or amphibian, whose body temperature is mostly determined by the surrounding environment.
Endocrine system: group of hormone-producing glands and their secretions (hormones) that have been related to aging.
Endotherm: a warm-blooded animal, like a bird and mammal, capable of regulating its internal temperature.
Eutherian: a placental mammal. All mammals are eutherians with the exception of marsupials and monotremes.
Exonuclease: enzyme that cleaves nucleotides from one end of a strand of nucleic acid.
Free radical theory of aging: theory that argues that aging is a result of damage accumulation caused by reactive oxygen species.
Gene: DNA sequence that encodes a protein and represents the basic unit of inheritance.
Genomics: the study of an organism's genome.
Genome: the full DNA sequence of an organism.
Geriatrics: the medical study of diseases and problems of the elderly.
Gerontology: the scientific study of the aging process and old age. In the context of senescence.info, gerontology refers to the biological study of aging and old age.
Hayflick's limit: the inability of cells to replicative indeterminately in culture.
Helicase: an enzyme that unwinds the DNA helix.
IMR: initial mortality rate. The age-independent mortality rate obtained from the Gompertz equation.
Iteroparous: an organism that may reproduce more than once during its lifespan.
Life expectancy: how long, on average, an animal can be expected to live. Can be used interchangeably with average lifespan and average longevity.
Life history: the changes organisms undergo from conception to death, focusing particularly on the schedule of reproduction and survival.
Lifespan: the period of time in which the life events of a species typically occur.
Longevity: the period of time an organism is expected to live under ideal circumstances.
Oocyte: a female gametocyte that develops into an ovum after two meiotic divisions.
Oogenesis: formation of new oocytes.
Maximum lifespan (tmax): the maximum period of time organisms of a given species can live. Usually refers to the longevity of the longest-lived individual of a given species.
Mechanical senescence: age-related changes that are a consequence of mechanical usage.
Mitochondrion: cellular organelle that produces most of the cell's energy.
MRDT: mortality rate doubling time. The time required for the mortality rate to double. Inferred from the Gompertz equation.
Negligible senescence: organisms in which the aging process cannot be detected.
Phenotype: the characteristics of an organism as determined by both genetic makeup and environmental influences.
Phylogeny: the evolutionary development and history of a species or taxonomic group of species.
Polyphenism: the ability of a single genome to give rise to two or more morphologies.
Polyphyodont: an animal that develops several sets of teeth successively throughout its life.
Polyploid: a cell with three or more sets of chromosomes.
Progeria: genetic disease resembling accelerated aging which typically affects children. Also called Hutchinson-Gilford syndrome.
Progeroid: a phenotype with features resembling accelerated aging.
Quiescent: in cellular biology, a quiescent cell is one that is not dividing.
Rate of living theory: theory that argues lifespan inversely correlates with metabolic rates. Not supported by recent data.
Reactive oxygen species (ROS): any of a number of highly reactive forms of oxygen that are potential sources of damage.
Semelparous: organisms that reproduce only once, usually followed by death.
Senescence: the fundamental process of aging or aging itself. Can also refer to cellular aging in some contexts.
Soma: the entire body of an organism with exception of the germ cells.
Stem cell: a cell that can be differentiated into any type of cell.
Strategies for engineered negligible senescence (SENS): a proposal by Aubrey de Grey that details how by reversing seven cellular and molecular age-related changes will allow researchers to cure aging.
Stress-induced premature senescence (SIPS): the way subcytotoxic stress can accelerate the appearance of the senescent phenotype in cells.
Supercentenarian: someone 110 years-old or older.
Topoisomerase: an enzyme that regulate the supercoiling structure of the DNA.
Taxon (plural: taxa): a taxonomic group of any rank.
Telomeres: the long end sequences of a DNA strand occurring at the tip of the chromosomes that appear to be associated with replicative senescence.
Telomerase: enzyme that adds telomeric sequences to the telomeres and has been associated with cellular immortality.
Werner syndrome (WS): genetic disease resembling accelerated aging that typically has an adult onset.
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