X chromosome

the sex chromosome that is responsible for determining femaleness in humans and other mammals. The body cells of normal females possess two X chromosomes (XX), whereas males have one X chromosome and one Y chromosome (XY). In humans, various authorities estimate that the X chromosome carries between 1,000 and 2,000 genes, including many responsible for hereditary diseases (see sex-linked). Abnormal numbers of X chromosomes lead to genetic imbalance and a range of disorders and syndromes. See also fragile X syndrome.

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

February 16th 2025

reasonable accommodations

adjustments made within an employment or educational setting that allow an individual with a physical, cognitive, or psychiatric disability to perform essential functions. These adjustments might include installing ramps in an office cafeteria for wheelchair accessibility, altering the format of a test for a person with learning disabilities, or providing a sign language interpreter for a person with hearing loss. Provisions for reasonable accommodations must be made by employers and educators according to the 1990 Americans With Disabilities Act and the 1973 Rehabilitation Act. See undue hardship.