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The following Scientific Terms are defined as follows:
Gamete
Mature male or female reproductive cell (sperm or ovum) with a haploid set of chromosomes (23 for humans)
Gel Electrophoresis
a DNA separation technique that is very important in DNA sequencing. Standard sequencing procedures involve cloning DNA fragments into special sequencing cloning vectors that carry tiny pieces of DNA. The next step is to determine the base sequence of the tiny fragments by a special procedure that generates a series of even tinier DNA fragments that differ in size by only one base. These nested fragments are separated by gel electrophoresis, in which the DNA pieces are added to a gelatinous solution, allowing the fragments to work their way down through the gel. Smaller pieces move faster and will reach the bottom first. Movement through the gel is hastened by applying an electrical field to the gel.
Gene
The fundamental physical and functional unit of heredity. A gene is an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional product (i.e., a protein or RNA molecule).
Gene expression
The process by which a gene's coded information is converted into the structures present and operating in the cell. Expressed genes include those that are transcribed into mRNA and then translated into protein and those that are transcribed into RNA but not translated into protein (e.g., transfer and ribosomal RNAs).
Gene family
Group of closely related genes that make similar products.
Gene mapping
Determination of the relative positions of genes on a DNA molecule (chromosome or plasmid) and of the distance, in linkage units or physical units, between them.
Gene product
The biochemical material, either RNA or protein, resulting from expression of a gene. The amount of gene product is used to measure how active a gene is; abnormal amounts can be correlated with disease causing alleles.
Genetic code
The sequence of nucleotides, coded in triplets (codons) along the mRNA, that determines the sequence of amino acids in protein synthesis. The DNA sequence of a gene can be used to predict the mRNA sequence, and the genetic code can in turn be used to predict the amino acid sequence.
Genetics
The study of the patterns of inheritance of specific traits.
Genome project
Research and technology development effort aimed at mapping and sequencing some or all of the genome of human beings and other organisms.
Genomic library
A collection of clones made from a set of randomly generated overlapping DNA fragments representing the entire genome of an organism.
Genomic sequence
The order of the subunits, called bases, that make up a particular fragment of DNA in a genome. DNA is a long molecule made up of four different kinds of bases, which are abbreviated A, C, T, and G. A DNA fragment that is 10 bases long might have a base sequence of, for example, ATCGTTCCTG. The particular sequence of bases encodes important information in an individual's genetic blueprint, and is unique for each individual (except identical twins).
Guanine (G)
A nitrogenous base, one member of the base pair GC guanine and cytosine).
Gene Therapy
The technology that uses genetic material for therapeutic purposes. This genetic material can be in the form of a gene, a representative of a gene or even a small fragment of a gene. The introduced genetic material can be therapeutic in several ways: It can make a protein that is defective or missing in the patient's cells (as would be the case for a genetic disorder), or one which will correct or modify a particular cellular function, or a protein that elicits an immune response. In gene therapy approaches, the genetic material may be introduced into the patient in several different ways. It can be directly injected for some applications in a process known as genetic vaccination, or it can be introduced by using bioengineered viruses that will carry the therapeutic gene as part of their own genetic cargo and deliver it into the cell.
Genome
All the genetic material in the chromosomes of a particular organism; its size is generally given as its total number of base pairs.
Genomics
The study of genomes, which includes genome mapping, gene sequencing and gene function.