Pair (bp): Nucleotide bases (adenine, thymine, guanine and cytosine)
are the building blocks of DNA. Two molecules of nucleotide bases held
together by weak bonds. Two strands of DNA are held together in the
shape of a double helix by the bonds between base pairs. The number
of base pairs is used to describe the size of a DNA molecule.
The self-replicating genetic structure of cells containing the cellular
DNA that bears in its nucleotide sequences the linear array of genes.
In prokaryotes, chromosomal DNA is circular, and the entire genome is
carried on one chromosome. Plant genomes consist of a number of chromosomes
whose DNA is associated with different kinds of proteins.
An exact copy made of biological material such as a DNA segment
(a gene or other region), a whole cell, or a complete organism.
Vector: A piece of DNA, such as a plasmid, into which a DNA segment
can be inserted, transferred into an organism, and replicated or reproduced.
(deoxyribonucleic acid): The molecule that encodes genetic information.
DNA is a double stranded molecule held together by weak bonds between
base pairs of nucleotides. The four nucleotides in DNA contain the bases:
adenine (A), guanine (G), cytosine (C), and thymine (T). In nature,
base pairs form only between A and T and between G and C; thus the base
sequence of each single strand can be deduced from that of its partner.
Expressed Sequence Tag: A unique, short DNA sequence derived from
a cDNA library. ESTs are useful for localizing and orienting the mapping
and sequence data reported from many different laboratories and serve
as identifying landmarks on the developing physical map of a plant genome.
Pattern: Gene expression is the process by which a gene's coded
information is converted into the structures or molecules present and
operating in the cell. Expression pattern refers to a set of genes expressed
under a set conditions (e.g. genes expressed in plants grown under drought
Genomics: Studies of the relationship between the structure and
organization of the genome and the function of the genome as it directs
growth, development, physiological activities, and other life processes
of the organism.
A public database where DNA sequences are deposited and made public.
It is operated and supported by the National Library of Medicine, part
of the National Institutes of Health, and is part of an international
consortium of a gene sequence database.
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).
Map: A map of the relative positions of genetic loci on a chromosome,
determined on the basis of how often the loci are inherited together.
The study of the patterns of inheritance of specific traits.
All the genetic material in the chromosomes of a particular
organism; its size is generally given as its total number of base
Project: Research and technology development effort aimed at
mapping and sequencing some or all of the genome of human beings
and other organisms.
Throughput Biology: An experimental approach that generates
massive amounts of raw data at the production scale using highly
automated technologies such as genome sequencing technology or microarray
technology, and processes the data by a batch method using computational
and other information management tools.
Genome Project: The national effort, led by DOE and NIH, was started in the
late 1980's. It includes several projects to (1) create an ordered
set of DNA segments from known chromosomal locations, (2) develop
new computational methods for analyzing genetic map and DNA sequence
data, and (3) develop new techniques and instruments for detecting
and analyzing DNA. While the ultimate objective is to understand
the structure, organization and function of the human genome, the
Human Genome Project supports studies on several model microbial
and animal genomes. No plant genomes are targeted by the Human Genome
The study of the application of computer and statistical techniques
to the management of information. In genome projects, informatics
includes the development of methods to search databases quickly,
to analyze DNA sequence information, and to predict protein sequence
and structure from DNA sequence data.
An unordered collection of clones (i.e., cloned DNA from a particular
organism), whose relationship to each other can be established by
Technology: New approach to the study of how large numbers of
genes interact with each other. This technology provides a quantitative
assessment of how a cell's regulatory networks control extensive
gene sets simultaneously. The method uses a robot to precisely apply
tiny droplets containing functional DNA to glass slides. Researchers
then attach fluorescent labels to DNA from the cell they are studying.
The slides are put into a scanning microscope that can measure the
brightness of each fluorescent dot; brightness reveals how much
of a specific DNA fragment is present, an indicator of how active
Map: A map of the physical locations of identifiable landmarks
on DNA (e.g., restriction enzyme cutting sites, genes); distance is
measured in base pairs. The highest resolution map would be the complete
nucleotide sequence of the chromosomes.
Genetics: An experimental approach that begins with information
about the primary DNA or protein sequence and uses this knowledge
to generate targeted mutations (heritable changes) or altered expression
levels. Observation of the resulting effects on the organism (a physical
attribute such as the color of the flower or the shape of the leaf)
yields information about the physiological function of the gene or
protein. This is the reverse strategy to a classical genetics approach
that proceeds from observing a defined genetic trait towards obtaining
sequence information for a specific gene.
Determination of the order of nucleotides (base sequences) in
a DNA or RNA molecule or the order of amino acids in a protein.
Genomics: Studies of the structure and organization of the genome
including DNA sequencing and physical and genetic mapping.
Map: Chromosomal maps showing the collinear relationships between
the genomes of different organisms. Often these chromosomal regions
from related organisms (such as various grass species) contain corresponding
genetic information and similar gene order.
Transfer: The process of converting scientific findings from research
laboratories into useful products by the commercial sector.