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  2. Sex chromosome - Wikipedia

    en.wikipedia.org/wiki/Sex_chromosome

    The 23rd pair of chromosomes are called allosomes. These consist of two X chromosomes in females, and an X chromosome and a Y chromosome in males. Females therefore have 23 homologous chromosome pairs, while males have 22. The X and Y chromosomes have small regions of homology called pseudoautosomal regions. An X chromosome is always present as ...

  3. XY sex-determination system - Wikipedia

    en.wikipedia.org/wiki/XY_sex-determination_system

    In this system, the sex of an individual usually is determined by a pair of sex chromosomes. Typically, females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Males typically have two different kinds of sex chromosomes (XY), and are called the heterogametic sex. [1]

  4. Sexual differentiation in humans - Wikipedia

    en.wikipedia.org/wiki/Sexual_differentiation_in...

    Most mammals, including humans, have an XY sex-determination system: the Y chromosome carries factors responsible for triggering male development. In the absence of a Y chromosome, the fetus will undergo female development. This is because of the presence of the sex-determining region of the Y chromosome, also known as the SRY gene. [5]

  5. Sex-determination system - Wikipedia

    en.wikipedia.org/wiki/Sex-determination_system

    No genes are shared between the avian ZW and mammal XY chromosomes [26] and the chicken Z chromosome is similar to the human autosomal chromosome 9, rather than X or Y. This suggests not that the ZW and XY sex-determination systems share an origin but that the sex chromosomes are derived from autosomal chromosomes of the common ancestor of ...

  6. XXYY syndrome - Wikipedia

    en.wikipedia.org/wiki/XXYY_syndrome

    48,XXYY syndrome is a condition related to the X and Y chromosomes (the sex chromosomes). People normally have 46 chromosomes in each cell. Two of the 46 chromosomes, known as X and Y, are called sex chromosomes because they help determine whether a person will develop male or female sex characteristics. Females typically have two X chromosomes ...

  7. Sex chromosome anomalies - Wikipedia

    en.wikipedia.org/wiki/Sex_chromosome_anomalies

    Sex chromosome anomalies belong to a group of genetic conditions that are caused or affected by the loss, damage or addition of one or both sex chromosomes (also called gonosomes). In humans this may refer to: 45, X, also known as Turner syndrome; 45,X/46,XY mosaicism, also known as X0/XY mosaicism and mixed gonadal dysgenesis; 46, XX/XY

  8. Human genome - Wikipedia

    en.wikipedia.org/wiki/Human_genome

    [4] [3] The human Y chromosome, consisting of 62,460,029 base pairs from a different cell line and found in all males, was sequenced completely in January 2022. [5] The current version of the standard reference genome is called GRCh38.p14 (July 2023). It consists of 22 autosomes plus one copy of the X chromosome and one copy of the Y chromosome.

  9. Homologous chromosome - Wikipedia

    en.wikipedia.org/wiki/Homologous_chromosome

    So, humans have two sets of 23 chromosomes in each cell that contains a nucleus. One set of 23 chromosomes (n) is from the mother (22 autosomes, 1 sex chromosome (X only)) and one set of 23 chromosomes (n) is from the father (22 autosomes, 1 sex chromosome (X or Y)). Ultimately, this means that humans are diploid (2n) organisms. [2]