Biology Reference
In-Depth Information
Glossary
Allele:
alternative forms of a gene or section of DNA at a given genetic locus.
Allelic Drop Out:
non-detection of an allele at a given locus. This results in only
one of the two alleles being detected at a heterozygous locus.
Allelic Ladder:
a mixture of all the common alleles at a given locus. The allelic
ladder allows comparison with the unknown alleles and assists in allelic designation.
Amplifiable Fragment Length Polymorphisms (AMP-FLPs):
polymorphic loci
where alleles differ in the number of tandem core repeats. Alleles are typically
between
500 bp
and
1000 bp
in
length.
An
example
of
an
AMP-FLP
is
the
locus D1S80.
Autosome:
a non-sex chromosome. In humans there are the 22 pairs of autosomal
chromosomes; these do not include the X and Y sex chromosomes.
bp:
base pair - two complementary nucleotides in double-stranded DNA. Adenine
pairs with thymine and guanine pairs with cytosine.
Chromosome:
a single molecule of double-stranded DNA associated with proteins
to form a highly ordered structure. Chromosomes are located in the cell nucleus of
eukaryotes and are visible with light microscopy only during cell division when they
become highly condensed.
CODIS loci:
the FBI defined a set of 13 STR markers for use in forensic analysis.
Diploid:
presence of two sets of chromosomes in a cell and therefore containing two
copies of the genome.
DNA polymerase:
an enzyme that catalyses the formation of a complementary DNA
strand in the 5
-3
direction acting on a template DNA strand.
Electrophoresis:
separation of charged molecules through a matrix. DNA is nega-
tively charged and will migrate from the cathode (
−
ve) to the anode (
+
ve) when an
electric current is applied across the matrix.
Euchromatin:
part of the chromosome that is loosely packed in the interphase of
the cell cycle. Most of the transcribed regions of the genome are located within the
euchromatin.
