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Glossary of Genetics TermsA B C DEF G H I J K L M N O PQ R S TU V W X Y Z Clicking a letter will scroll the page to the relevant section below. It is not the intention of this page to provide exhaustive genetic terms and definitions, rather to be a useful resource in the interpretation of the information provided in this web. If you don't find a definition for a term you are looking for, try one of these useful genetics glossaries:
AAutosomal a genetically determined trait that is located on an autosome. Autosome a term referring to any chromosome that is not a sex determining chromosome. In humans, it is any one of the 22 pairs of chromosomes other that the X chromosome or Y chromosome.
BBase a molecule that is part of DNA, which codes for genes. A DNA base is one of the amino acids adenine (A), cytosine (C), guanine (G), or thymine (T). Birth Defect an abnormality that is present at birth, which
may or may not be the result of a gene or genes. CCell The basic unit of living organisms that are responsible for many of the biochemical processes of life. A human cell contains the complete human genome. Chromosome is a complex structure resulting from coiling of a large DNA molecule and contains the majority of human genes. In the human genome there are typically 23 pairs or 46 total chromosomes. Congenital a condition that is present at birth. Connexin 26 (also known as GJB2) is the name given to a particular gene, which when mutated, is known to cause non-syndromic hearing loss. It is primarily autosomal recessive mutation, which means that two copies of the gene must be present in order for hearing loss to occur. It is thought responsible for 50% non-syndromic recessive hearing loss. (see also connexin 30). Connexin 30 (also known as GJB6) is the name given to a particular gene, which when mutated, is known to cause non-syndromic hearing loss. It is primarily autosomal recessive mutation, which means that two copies of the gene must be present in order for hearing loss to occur. (see also connexin 26)
D E FDNA (deoxyribonucleic acid) a complex linear molecule composed of several components including the amino acids adenine (A), cytosine (C), guanine (G), and thymine (T). These amino acids may also be referred to as bases. The variable sequences of these amino acids on the DNA strand encode for genes. Dominant Gene a gene that requires only one of two copies (inherited from either parent) to cause a trait to express (see also recessive gene).
GGene is a discrete segment of information on the chromosome, encoded by amino acids on the DNA, that confers a trait or an aspect of a trait in an organism. Genetics is the study of hereditary variations in organisms resulting from genes. It focuses on the specific gene structures and gene variants with the aim to understand genetic traits and their inheritance. Genome is the sum of all of an organism's genetic makeup. Genomics is the study of the genome in its entirety and its complex actions. The term genome is used to refer to all the DNA contained in a cell including both the chromosomes within the nucleus and the DNA in the mitochondria. Genotype is the genetic constitution of a hereditary trait. (see also phenotype)
H I J KHereditary A trait that is transmitted genetically from one generation to the next.
LLocus The location of a gene on the chromosome.
MMedical Home is not just a building, house or hospital, but a team approach to providing health care. A Medical Home originates in a primary health care setting that is family-centered and compassionate. A partnership develops between the family and the primary health care practitioner. Together they access all medical and non-medical services needed by the child and family to achieve maximum potential. The Medical Home maintains a centralized, comprehensive record of all health related services to promote continuity of care. Mitochondria are structures within a cell primarily responsible for producing most of the cell's required energy. There are typically several mitochondria within a given cell. Mitochondrial DNA is DNA separate from that on chromosomes and is contained within the mitochondria. Mitochondrial DNA is is only inherited through the mother. Since multiple mitochondria are present in a cell, multiple copies of mitochondrial DNA are also present. Mutation an event that results in an altered gene sequence that may cause a disease condition.
NNonsyndromic Hearing Loss hearing loss that occurs as an isolated finding caused by a single altered gene, which only has hearing loss as the resultant effect (see also syndromic hearing loss).
OOncogene A gene that can cause normal cells to become cancerous by effecting uncontrolled cell division.
PQPrelingual Hearing Loss hearing loss that occurs prior to normal speech development. Phenotype is the physical manifestation of a genetic trait, resulting from a specific genotype and its interaction with the environment. Postlingual hearing loss that occurs after speech development.
RRecessive Gene a gene that requires two copies (one inherited from each parent) to cause the trait to express (see also dominant gene).
SSex Chromosome the chromosomes whose genes confer the sex of the organism. In humans, it is the X chromosome and Y chromosome. Normally, men have an X and Y chromosome while women have two X chromosomes. Sex Linked Gene is a gene that is located on either of the sex chromosomes (X or Y). Special Health Care Needs a condition or conditions that require ongoing medical intervention beyond that required by a typical person. Syndrome is a constellation of 2 or more abnormalities that occur together more frequently than chance would predict. A syndromic diagnosis does not necessitate that all associated conditions present in an individual. Syndromic Hearing Loss is hearing loss that may have a single cause, but is accompanied by additional associated conditions other than hearing loss (see also nonsyndromic hearing loss).
TUTrait (genetic trait) a distinguishing heritable characteristic determined by a gene.
VWVariant (gene variant) a gene sequence that, through variation in order or composition, causes different genetic traits or phenotypes in a organism.
XX Chromosome A sex chromosome that confers femaleness in humans, in the absence of the Y chromosome. A normal complement for females is a pair of X chromosomes (XX) (see also Y Chromosome). YY Chromosome A sex chromosome that confers maleness in humans, when present in the cell. A normal complement for males is a X and a Y chromosome (XY) (see also X Chromosome).
ZZygote The cell from which an organism develops, that results from the fertilization of the egg by the sperm. The zygote normally caries the full genetic complement of the organism.
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