| Allele |
One of two or more different genes that occupy the same place on a chromosome, allowing hereditary variation. |
| Amino Acid |
One of the building blocks of proteins; there are 20 common amino acids. |
| Autosome |
A chromosome that is not a sex chromosome (any one but X and Y). |
| Biotechnology |
The use of the properties of living things to make products or services. Applications include the removal of pollutants from the environment and the bulk production of drugs, synthetic hormones, and foodstuffs. |
| Codominance |
See Incomplete Dominance. |
| Chromosomes |
Rod-shaped structures found in the nucleus of every cell in an organism. The DNA of an organism is located on the chromosome. In males, all body cells have an X and a Y chromosome, in addition to the 44 ordinary chromosomes. In females, all body cells have two X chromosomes in addition to the 44 ordinary chromosomes. |
| DNA |
Deoxyribonucleic acid; the molecule that stores and passes on genetic information from one generation to the next. |
| Dominant Trait |
A trait that produces the same phenotypic effect whether it was inherited homozygously or heterozygously; an allele that "masks" another. See also heterozygote, homozygote, phenotype, recessive trait. |
| Electrophoresis |
A method of separating DNA fragments of different lengths by placing them in agarose gel and running electric current through the gel. |
| Exon |
A segment of DNA that codes for a protein or regulates the activity of other genes. |
| Gene |
The basic unit of heredity, which is passed down from parent to offspring and can be transcribed into a protein chain. |
| Gene Therapy |
The therapeutic replacement of defective genes in an individual. |
| Genetic Diversity |
The number of different genetic combinations available in a given gene pool. |
| Genetic Engineering |
The scientific alteration of the genetic material of an organism. |
| Genetic Fingerprinting |
A method of identification exploiting differences in the number of repetitions of certain DNA sequences between individuals. A multi-locus probe produces a "fingerprint" that resembles a bar code; while a less definitive but more sensitive single-locus probe produces two distinct bars. This method is often used in forensic science. |
| Genetic Screening |
The process of testing individuals in a population for certain hereditary defects. |
| Genetics |
The study of heredity, or the passing on of traits from an organism to its offspring. |
| Genotype |
The genetic makeup or constitution of an organism. |
| Heredity |
The passing down of traits from parents to offspring. |
| Heterozygote |
A organism who possesses two different alleles of a given gene. See also allele. |
| Homozygote |
An organism who possesses two identical alleles of a given gene. See also allele. |
| Human Genome Project |
A internationally funded project that plans to identify both the functions of genes and their locations on the chromosomes. |
| Incomplete Dominance (Codominance) |
From Genethics: The Clash Between the New Genetics and Human Values: A condition in which a heterozygous offspring has a phenotype that is distinct from, and intermediate to, homozygous, parental phenotypes. See also heterozygote , homozygote , phenotype. |
| Intron |
A non-coding segment of DNA; edited out during the transcription process. |
| Mutagen |
A substance or agent that causes genetic mutations. |
| Mutation |
A change in the DNA of an organism. Classified as insertion (addition of a base), deletion (subtraction of a base), or substitution (replacement of one base with another). |
| Nucleotide |
A chemical (adenine, thymine, cytosine, and guanine) that makes up nucleic acid. On the DNA "ladder", adenine pairs with thymine and cytosine pairs with guanine. In RNA, uracil replaces thymine. |
| PCR Amplification |
Polymerase chain reaction; a method of amplifying (increasing the amount of) a given DNA sequence. |
| Phenotype |
The physical characteristics associated with a certain genotype. See also genotype. |
| Protein |
A fundamental component of all living cells made up of amino acids and coded for by DNA. |
| Recessive Trait |
A trait that only produces its phenotypic effect when inherited homozygously; a trait "masked" by a dominant trait. See also dominant trait. |
| RNA |
Ribonucleic acid; a class of nucleic acids similar to DNA but having a uracil base instead of a thymine base. |
| Traits |
Physical characteristics. |
| Transcription |
The synthesis of messenger RNA from a DNA template. |
| Transgenic Organism |
An organism that contains genes from other species. |
| Translation |
The synthesis of a protein from a messenger RNA template. |
| Sex-linked (X-linked) |
Linked to the X chromosome. X-linked disorders are recessive and occur only in males. This is because males have no second copy of the X chromosome to "obscure" the effects of the abnormal gene. |
| Vector |
A "vehicle" (virus, bacterium, etc.) used to get a foreign DNA sequence into a cell. |
Created by Kate Stafford and Michael Mannor for ThinkQuest.