Knowra Sex chromosome Sex chromosome A chromosome whose inheritance or gene content differs between sexes and contributes to sex determination or sex-specific traits. Common examples include the X and Y chromosomes in humans.
Sex-determination system : A biological mechanism that determines an organism’s sex, through chromosomes, genes, environmental cues, or their interactions. Chromosome-based systems are one way sex chromosomes direct developmental pathways.
XX-XY sex-determination system : A system in which females typically have two X chromosomes and males typically have one X and one Y. It is the familiar mammalian arrangement, but not the only sex-chromosome system.
Chromosome : A DNA molecule packaged with proteins that carries genetic information in a cell. Sex chromosomes are specialized members of this broader class of genetic structures.
Turner syndrome : A chromosomal condition in which a female has one complete or partial X chromosome instead of two complete copies. It illustrates how variation in X-chromosome number can affect development and health.
Y chromosome : A sex chromosome present in many male mammals, carrying genes including those involved in testis development. Its gene content and long-term evolutionary fate remain active research subjects.
SRY : A gene on the human Y chromosome that initiates testis development in typical male embryonic development. Its presence on the Y chromosome is a direct example of a sex-determining gene.
ZZ-ZW sex-determination system : A system in which males typically have two Z chromosomes and females have one Z and one W. It reverses which sex has matching sex chromosomes compared with the mammalian system.
Karyotype : The number and visual appearance of chromosomes in a cell or organism. Karyotypes display the sex-chromosome complement, such as XX or XY.
Klinefelter syndrome : A chromosomal condition in which a male typically has an additional X chromosome, often with a 47,XXY karyotype. It shows consequences of an extra sex chromosome in humans.
X chromosome : A sex chromosome found in at least one copy in most humans, with many genes unrelated to sex determination. Its dosage, expression, and effects across tissues continue to be investigated.
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