Dictionary > X linkage

X linkage

Definition
noun, plural: X linkages
(genetics) A form of sex linkage involving particularly the X chromosome
Supplement
The resulting phenotype or trait is due to the expression of a particular gene and when such gene occurs in the sex chromosome it is referred to as sex linkage. In mammals, including humans, the sex chromosomes are of two kinds: the X chromosome and the Y chromosome. Females typically possess two X chromosomes whereas males have one X chromosome (which is inherited from the female parent) and one Y chromosome (which is from the male parent). In this regard, sex linkage are of two forms, i.e. X linkage or Y linkage. X linkage is a sex linkage involving the X chromosome whereas Y linkage is a sex linkage involving the Y chromosome. Since there are more genes in the X chromosome than in the Y chromosomes there are more X-linked traits than Y-linked.
X linkage is the state of a genetic factor (gene) being borne on the X chromosome. The inheritance of these genes from the X chromosome is referred to as X-linked inheritance, and may either be recessive or dominant. For instance, a female offspring whose father has an X-linked dominant trait would manifest the trait as well whereas a male offspring would not since the X chromosome would be inherited from the mother lacking such trait. A mother carrying the X-linked dominant trait would have offspring with 50% chance of acquiring the trait. Examples of X-linked dominant inheritance are Alport’s syndrome, idiopathic hypoparathyroidism, Rett syndrome, and fragile X syndrome. When the X-linked trait is recessive, the mother would have a female offspring that does not manifest the trait but would be a carrier whereas a male offspring would show the trait as there is only one X chromosome and it comes from the mother. Examples of X-linked recessive inheritance are Hunter syndrome, haemophilia A and B, color blindness, and Wiskott-Aldrich syndrome.
Compare:

  • Y linkage

See also:

  • X-linked inheritance


    You will also like...

    3D rendering of an antibody
    Passive and Active Types of Immunity

    Lymphocytes are a type of white blood cell capable of producing a specific immune response to unique antigens. In thi..

    New Zealand - Biodiversity fauna
    New Zealand’s Biodiversity

    Find out more about New Zealand's unique biodiversity by exploring a range of different ecosystems and the key role of s..

    Cell Respiration
    Cell Respiration

    Cell respiration is the process of creating ATP. It is "respiration" because it utilizes oxygen. Know the different stag..

    Gibberellins and Gibberellic Acid
    Gibberellins and Gibberellic Acid

    This tutorial describes the role of gibberellin family in plants. Find out the effects of gibberellin on plant growth an..

    sponge
    Primitive Animals

    Life, as we know it today, is presumed to have started in the sea and many of them were likely eukaryotic animal-like or..

    Bryophytes
    Bryophytes

    Bryophytes (nonvascular plants) are a plant group characterized by lacking vascular tissues. They include the mosses, th..