Gene Cloning

450 Gene Cloning
Phenotype The observable characteristics of
an organism. The phenotype results from
genetic or environmental factors, or the
interactions between the two.
Phylogenetic tree A branching diagram showing
the evolutionary relationships between
organisms or molecules.
Plaque The clear area seen in a bacterial lawn
where bacteria have been infected and lysed
by bacteriophage.
Plasmid A small circular non-essential extra
chromosomal DNA molecule that replicates
autonomously. Plasmids are very widely used
as cloning vectors.
Polylinker In a cloning vector, a short synthetic
region containing the recognition
sequences for several restriction enzymes.
Also called a multiple cloning site.
Polymorphism The occurrence of two or
more variants of a gene or DNA sequence in a
population at a frequency that cannot be
accounted for by recurrent mutation. A variant
that occurs in less than 1% of the population
is considered a mutation rather than a
polymorphism.
Polyploid Having more than two complete
sets of chromosomes.
Another name for map-
Positional cloning
based cloning.
Pre-implantation Refers to an embryo fertilized
in vitro before it is transferred into the
uterus.
Prenatal
After conception and before birth.
Primer A short single-stranded DNA molecule,
often a synthetic oligonucleotide, which
provides a 3' hydroxyl for the initiation of
DNA synthesis by DNA polymerase.
Probe A short single-stranded DNA molecule,
often a synthetic oligonucleotide, which is
labeled and used to detect a complementary
sequence to which it hybridizes.
form of a matrix in which the frequency of
each amino acid at each position is recorded.
Prokaryote Organism without a membranebound
nucleus or other membrane bound
organelles. Bacteria and archaea are prokaryotes.
See eukaryote.
Promoter DNA sequence recognized by RNA
polymerase for subsequent initiation of
mRNA synthesis. Now often used to include
the regulatory sequences that affect RNA
polymerase binding.
Promoter probe A plasmid containing a
reporter gene without a promoter. Cloning of
a DNA fragment encoding a promoter
upstream of the reporter will result in expression
of the reporter allowing the identification
of promoter sequences and study of
their properties.
Proteome All of the proteins expressed by a
cell, tissue or organism at a particular time
under specific conditions.
Proteomics The large-scale analysis of all the
proteins in a cell or tissue at a specific time
and under specific conditions.
Reading frame A series of triplet codons starting
from a particular nucleotide. There are
three possible forward and three reverse
reading frames.
Recombinant Used in gene cloning to describe
a new combination of DNA fragments.
Recombination The process of breaking and
rejoining of DNA strands usually resulting in
the exchange of genetic material.
Regular expression Used in bioinformatics to
describe a string of characters that describes
a series of related DNA or amino acid
sequences.
Reporter gene A gene encoding a protein with
an easily detectable property or effect on the
organism’s phenotype. Used to detect and
measure gene expression and in promoter
probe vectors.
Profile In bioinformatics this is a description
of the members of a protein family in the
Reporter protein
reporter gene.
The protein product of a