A statistical parameter used in calculating BLAST scores that
can be thought of as a natural scale for scoring system. The
value lambda is used in converting a raw score (S) to a bit
score (S'). (NCBI)
An unordered collection of clones (i.e., cloned DNA from a
particular organism) whose relationship to each other can
be established by physical mapping.
See also: genomic library,
arrayed library (ORNL)
The proximity of two or more markers (e.g., genes, RFLP markers)
on a chromosome; the closer the markers, the lower the probability
that they will be separated during DNA repair or replication
processes (binary fission in prokaryotes, mitosis or meiosis
in eukaryotes), and hence the greater the probability that they
will be inherited together. (ORNL)
Linkage disequilibrium
Where alleles occur together more often than can be accounted
for by chance. Indicates that the two alleles are physically
close on the DNA strand.
See also: Mendelian inheritance
(ORNL)
A map of the relative positions of genetic loci on a chromosome,
determined on the basis of how often the loci are inherited
together. Distance is measured in centimorgans (cM). (ORNL)
Local Alignment
The alignment of some portion of two nucleic acid or protein
sequences (NCBI)
Localisation
Numbers of domains that are thought from SwissProt annotations
to be present in different cellular compartments (cytoplasm,
extracellular space, nucleus, and membrane-associated) are shown
in annotation pages. (SMART)
Localize
Determination of the original position (locus) of a gene or
other marker on a chromosome. (ORNL)
The position on a chromosome of a gene or other chromosome
marker; also, the DNA at that position. The use of locus is
sometimes restricted to mean expressed DNA regions.
See also: gene expression
(ORNL)
Long-Range Restriction Mapping
Restriction enzymes are proteins that cut DNA at precise locations.
Restriction maps depict the chromosomal positions of restriction-enzyme
cutting sites. These are used as biochemical "signposts,"
or markers of specific areas along the chromosomes. The map
will detail the positions where the DNA molecule is cut by particular
restriction enzymes. (ORNL)
Low Complexity Region (LCR)
Regions of biased composition including homopolymeric runs,
short-period repeats, and more subtle overrepresentation of
one or a few residues. The SEG program is used to mask or filter
LCRs in amino acid queries. The DUST program is used to mask
or filter LCRs in nucleic acid queries. (NCBI)
