A sex chromosome in certain animals, such as chickens, turkeys, and moths. In humans, males are XY and females XX, but in animals with a Z chromosome, males are ZZ and females are WZ.

Zeta-chain-associated protein kinase 70. A member of the protein tyrosine kinase family, ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 is expressed in T cells and tumors of T-cell lineage. A high level of ZAP-70 expression appears restricted to T-cell […]

‘When you hear hoof beats, think of horses, not zebras.’ For example, when someone develops a mild transient cough, a virus infection is the most logical and likely cause, and tuberculosis is a zebra.

A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene scotches prenatal development at its […]

A technique in which a woman’s egg is fertilized outside the body, then implanted in one of her fallopian tubes. This technique is one of the methods used to overcome infertility, the inability of couples to produce offspring on their own. First, the egg and the male sperm needed to fertilize it are harvested. Then […]

The branch of the law that deals with the application of law to medicine or, conversely, the application of medical science to legal problems. Medical jurisprudence may be involved in cases concerning genetic relationships (eg, paternity testing) or injury or death resulting from violence. An autopsy may be done to help determine the agent of […]

Incomplete paralysis or slight paralysis.

Genome, mustard Arabidopsis thaliana: See: Arabidopsis thaliana genome.

Fewer sperm than usual. Azospermia, by contrast, means absolutely no sperm at all.

A localized reaction that involves redness, itching, and burning that occurs where the skin has come into contact with an allergen (an allergy-causing substance) or an irritant such as an acid, a cleaning agent, or another chemical.