One of the two chromosomes that specify the sex of an organism. Humans have two kinds of sex chromosomes, one called the X and the other Y. Normal females possess two X chromosomes and normal males possess one X and one Y.

Undifferentiated cells in a tissue. These cells can grow into any of the types of specialised cells in that tissue.

One of two or more alternative forms of a gene. A person may have two copies of the same allele which would be called homozygous or two different forms which is heterozygous. Different alleles arise from changes in the base sequence of that gene through mutations. For example, the gene for eye colour has different alleles resulting in blue or brown [..]

A laboratory animal with a specific disease that researchers can experiment with to find out more about that disease and how it occurs in humans. Animal models are used to learn more about the causes of a disease, its diagnosis in humans, and to investigate or trial new treatments or preventative actions. Animal models of disease may occur naturall [..]

Amino acids are the building blocks of proteins. There are 20 known amino acids found in living organisms. The sequence of amino acids in a protein determines its function. This sequence of amino acids is determined by the sequence of bases found in the gene coding for that protein.

A procedure by which a small amount of amniotic fluid (the fluid surrounding a baby in the womb) is drawn out using a needle inserted in to the mother's abdomen. This fluid contains cells from the baby and can be used to test for chromosomal and genetic disorders, as well as certain birth defects before the baby is born.

A condition that is due to a reduced number of red blood cells or reduced amounts of haemoglobin within them. This results in reduced oxygen carrying capacity and reduced aerobic activity in body cells.

Proteins produced by the immune system of humans and other vertebrates in response to the presence of a specific antigen.

Substance that prevents blood from clotting.

A sequence of three bases in a molecule of transfer RNA (tRNA) that binds to a complementary codon in messenger RNA (mRNA). Each anticodon designates a specific amino acid to be added to a growing polypeptide.