One of a pair of genes whose action is expressed even when only one copy is present

1. one that comes before or gives rise to another 2. in chemistry, one substance that comes before or gives rise to another often more stable substance

One of the five classes of immunoglobulins. One of the most common immunoglobulins, it is present in body secretions and is the chief antibody in the mucous membranes of the gastrointestinal and respiratory tract and in saliva and tears.

A rare genetic condition in boys and men caused by an extra X chromosome. (Males normally have one X and one Y chromosome.) The presence of the extra X chromosome may or may not produce obvious signs and symptoms (usually in teens and adults), such as low testosterone, small penis and testicles, enlarged breasts, tall stature and/or behavioral...

Any one of the group of fungi that cause infection of the skin, hair, or nails

One of the two membranes that surrounds each lung and lines the chest cavity

One of the two main branches of the windpipe (trachea) that lead directly to the lungs

Genes are instructions for our body. Normally genes are inherited in pairs – one from each parent. A dominant gene needs only one of the pair to cause a change. A recessive gene will not act on the body unless both of the pair are the same. For example, the gene for cystic fibrosis is recessive and will not cause disease if a normal gene (which is...

Any one of the possible alternative forms in which a specific gene can occur

Having two different copies of a particular gene, one of which may be abnormal