Autosomes The chromosomes which are
not sex chromosomes. There are 22 pairs of autosomes in
humans.
Blastocyst Very early mammalian
embryo, consisting of about 100 cells. The blastocyst comprises a
hollow ball of cells that will give rise to the placenta,
surrounding a smaller, denser ball of cells that will give rise to
the body of the embryo .
Chromatin DNA in combination with
its associated proteins, especially histone proteins.
Concordance The degree to which two
genetically identical individuals are identical
phenotypically.
CpG A cytosine nucleotide followed
by a guanine nucleotide in DNA. CpG motifs can undergo methylation
on the C.
Discordance The degree to which two
genetically identical individuals are non-identical
phenotypically.
DNA replication Copying DNA to
create new DNA molecules which are identical to the
original.
DNMT DNA methyltransferase. An
enzyme that can add methyl groups to cytosine bases in
DNA.
Epigenome All the epigenetic
modifications on the DNA genome and its associated histone
proteins.
ES Cells Embryonic stem cells.
Pluripotent cells experimentally derived from the Inner Cell
Mass.
Exon Region of a gene that codes
for a section that is present in the final version of the mRNA
copied from that gene. Most, but not all, exons encode amino acids
in the final protein produced from a gene.
Gamete An egg or a
sperm.
Genome All the DNA in the nucleus
of a cell.
Germline The cells that pass on
genetic information from parent to child. These are the eggs and
the sperm (and their precursors).
HDAC Histone deacetylase. An enzyme
that can remove acetyl groups from histone proteins.
Histones Globular proteins that are
closely associated with DNA, and which can be epigenetically
modified.
Imprinting Phenomenon in which
expression of certain genes depends on whether they were inherited
from the mother or the father.
Inner Cell Mass (ICM) The
pluripotent cells in the inside of the early blastocyst that will
give rise to all the cells of the body.
Intron Region of a gene that codes
for a section that is removed from the final version of the mRNA
copied from that gene.
iPS Cells Induced pluripotent stem
cells. Produced by reprogramming mature cells with specific genes
that cause terminally differentiated cells to revert into
pluripotent ones.
kb Kilobase. 1,000 base
pairs.
miRNA Micro RNA. Small RNA
molecules that are copied from DNA but that don’t code for
proteins. miRNAs are a subset of ncRNAs
mRNA Messenger RNA. Copied from DNA
and codes for proteins.
ncRNA Non-coding RNA. Copied from
DNA and doesn’t code for proteins.
MZ Twins Monozygotic/ identical
twins, formed when an early embryo splits in two.
Neurotransmitter A chemical
produced by one brain cell that acts on another brain cell to alter
its behaviour.
Nucleosome Combination of eight
specific histone molecules with DNA wrapped around
them.
Phenotype The observable
characteristics or traits of an organism.
Pluripotency The ability of a cell
to give rise to most other cell types. Typically, pluripotent
mammalian cells give rise to all cells of the body, but not the
cells of the placenta.
Priomordial germ cells Very
specialised cells created in early development, which give rise
ultimately to the gametes.
Promoter Region in front of a gene
that controls how a gene is switched on.
Pronucleus The nucleus of a sperm
or egg, following entry of a sperm into an egg, but before the two
nuclei fuse.
Retrotransposons Unusual segments
of DNA that don’t code for protein and can move between different
locations in the genome. Believed to have originated from
viruses.
RNA Single stranded copy of a
specific region of DNA. The term RNA stands for ribonucleic acid.
It includes various different classes of RNA molecules including
miRNA, mRNA and ncRNA.
Sex chromosomes The X and Y
chromosomes that govern sex determination in mammals. Normally,
females have two X chromosomes and males have one X and one Y
chromosome.
Somatic cells Cells of the
body.
Somatic Cell Nuclear Transfer
(SCNT) The transfer of the nucleus from a mature cell into
another cell, usually an egg.
Somatic mutations Mutations that
happen in the cells of the body, rather than ones that have been
inherited via sperm or eggs.
Stochastic variation A random
change or fluctuation.
Totipotency The ability of a cell
to give rise to all cells of the body and the
placenta.
Transcription Copying DNA to create
RNA molecules.
Transgenerational inheritance The
phenomenon in which phenotypic changes in one generation are passed
on to the next, without any alteration in the genetic
code.
Uniparental disomy A situation
where both members of a pair of chromosomes have been inherited
from one parent, rather than one from each parent. For example,
maternal uniparental disomy of chromosome 11 would mean both copies
of chromosome 11 had come from the mother.
Vernalisation The process where
plants need a period of cold before they will flower.
Zygote The totipotent cell formed
when an egg and a sperm fuse.