25
Dec
2009
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Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

L

L
Leucine.
lagging strand
The DNA strand synthesized in a discontinuous fashion, 5' to 3' away from the replication fork.
leading strand
The DNA strand synthesized in a continuous fashion, 5' to 3' toward the replication fork.
length abridgment
The gradual shortening of pseudogenes during evolution that is caused by an excess of deletions over insertions.
lethal mutation
A mutation that causes either death or sterility of its homozygous carriers.
ligation
The formation of a phosphodiester bond to link two adjacent bases separated by a nick in double-stranded DNA. Used to link sticky ends produced by restriction-endonuclease digestion. The process is catalyzed by the enzyme ligase.
likelihood ratio test
A statistical test for goodness-of-fit.
LINE (Acronym of Long INterspersed Element)
An interspersed repetitive sequence typically longer than 5,000 base pairs found in large numbers in the genomes of multicellular eukaryotes.
linkage
A condition in which two or more nonallelic genes reside in close proximity to each other and tend to be inherited together.
linkage disequilibrium
Non-random, non-Mendelian association among polymorphic sites or alleles among loci.
localized repeated sequences
Tandemly arrayed, repetitive sequences, usually made up of short simple repeated motifs (e.g., satellite DNA)
locus (plural loci)
The site on a chromosome where a particular gene or DNA segment is located.
lowly repetitive genes
Genes appearing in only a few copies in the haploid genome.
LRT
(see likelihood ratio test)