A short strand of RNA that acts as a starting point for DNA replication.

Material that emits radiation energy.

When the allele of a gene shows its effect only if there are two copies in the genome, for example the allele for blue eyes. 

Doughnut shaped cells found in the blood. They are responsible for carrying oxygen to all of the organs and tissues in the body. 

The genome sequence of an organism that is used as a representative example of the set of genes in the genome of that particular species. It can be used as a template for assembling and comparing individual genomes of the same species.

A layer of tissue lining the inner surface of the eye that contains cells sensitive to light. These cells trigger nerve impulses that pass, via the optic nerve, to the brain, forming an image and enabling us to see.

A group of RNA viruses which insert a DNA copy of their genome into the host cell in order to replicate, for example, HIV.

Small organelles found in our cells. They are responsible for assembling amino acids into proteins during protein synthesis. 

Small organelles found in our cells. They are responsible for assembling amino acids into proteins during protein synthesis. 

A group of bacteria that cause a wide spectrum of infectious diseases, including food poisoning and typhoid fever.

The process of breeding animals or plants to bring out particular desirable characteristics in future generations.

Term to describe DNA after replication, DNA molecules consist of one brand new and one of the original chains of nucleotide bases.

A group of closely related microorganisms distinguished by a common set of antigens.

A genetic disorder characterised by a reduced number of immune cells. Can be treated with gene therapy. 

A chromosome that contains gender-specific genetic information. In humans, men have an X chromosome and a Y chromosome whereas women have two X chromosomes. Some genetic disorders are a result of changes in the sex chromosomes.  

An inherited blood disorder in which red blood cells, which usually carry oxygen, develop abnormally. 

Medical procedure where a doctor looks into the rectum and bowel of a patient using an instrument, inserted into the bottom, called a sigmoidoscope.

Disorders caused by defects in one particular gene, and often have simple and predictable inheritance patterns.

Most common type of genetic variation among people. They represent a change in a single DNA base (A, C, G or T) in the DNA code. 

Any cell forming the body of an organism. Includes all cells except the sex cells/germ cells.

A group of closely-related organisms that have common physical and genetic characteristics and are able to interbreed to produce fertile offspring.

A colourless liquid that is secreted from the blood into specific parts of the brain to help maintain the critical pressure within the brain and spinal cord. 

A group of infections caused by the bacterium Staphylococcus. The most common of this group of bacteria is Staphylococcus aureus. 

Cells that have the potential to develop into many different cell types in the body during early life and growth.

Any type of infection caused by the group of bacteria Streptococcus. Infections vary in severity from mild throat infections to pneumonia. 

Serious medical condition that occurs when the blood supply to part of the brain is cut off and brain cells are damaged or die.

The likelihood of being vulnerable to a particular thing, for example, a genetic disease.

Subset of lymphocyte white blood cell that play a central role in human immunity.

This is an enzyme that adds the DNA sequence repeat TTAGGG, also known as telomeres, to the ends of chromosomes.

Sections of DNA found at the ends of each of our chromosomes, consisting of the same sequence of bases repeated over and over. They protect the ends of chromosomes by forming a cap.