Gene Cloning and DNA Analysis: An Introduction, Sixth Edition ...

Glossary 305
Liposome A lipid vesicle sometimes used to introduce DNA into an animal or plant
cell.
Lysogen A bacterium that harbors a prophage.
Lysogenic infection cycle The pattern of phage infection that involves integration of
the phage DNA into the host chromosome.
Lysozyme An enzyme that weakens the cell walls of certain types of bacteria.
Lytic infection cycle The pattern of infection displayed by a phage that replicates and
lyses the host cell immediately after the initial infection. Integration of the phage
DNA molecule into the bacterial chromosome does not occur.
M13 A bacteriophage that infects E. coli, derivatives of which are used as cloning vectors.
Mapping reagent A collection of DNA fragments spanning a chromosome or the entire
genome and used in STS mapping.
Massively parallel A high throughput sequencing strategy in which many individual
sequences are generated in parallel.
Mass spectrometry An analytical technique in which ions are separated according to
their mass-to-charge ratios.
Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) A type of mass
spectrometry used in proteomics.
Melting temperature (T m ) The temperature at which a double-stranded DNA or
DNA–RNA molecule denatures.
Messenger RNA (mRNA) The transcript of a protein-coding gene.
Microarray A set of genes or cDNAs immobilized on a glass slide and used in transcriptome
studies.
Microinjection A method of introducing new DNA into a cell by injecting it directly
into the nucleus.
Microsatellite A polymorphism comprising tandem copies of, usually, two-, three-,
four- or five-nucleotide repeat units. Also called a short tandem repeat (STR).
Minimal medium A defined medium that provides only the minimum number of different
nutrients needed for growth of a particular bacterium.
Mitochondrial DNA The DNA molecules present in the mitochondria of eukaryotes.
Mitochondrial Eve The woman who lived in Africa between 140,000 and 290,000
years ago and who carried the ancestral mitochondrial DNA that gave rise to all the
mitochondrial DNAs in existence today.
Modification interference assay A technique that uses chemical modification to identify
nucleotides involved in interactions with a DNA binding protein.
Molecular clock An analysis based on the inferred mutation rate that enables times to
be assigned to the branch points in a gene tree.
Multicopy plasmid A plasmid with a high copy number.
Multigene family A number of identical or related genes present in the same organism,
usually coding for a family of related polypeptides.
Multigene shuffling A directed evolution strategy that involves taking parts of each
member of a multigene family and reassembling these parts to create new gene variants.
Multiplex PCR A PCR carried out with more than one pair of primers and hence
targeting two or more sites in the DNA being studied.
Multiregional evolution A hypothesis that holds that modern humans in the Old World
are descended from Homo erectus populations that left Africa over one million years
ago.
Nick A single-strand break, involving the absence of one or more nucleotides, in a
double-stranded DNA molecule.