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  2. XY sex-determination system - Wikipedia

    en.wikipedia.org/wiki/XY_sex-determination_system

    In the XY sex-determination system, the female-provided ovum contributes an X chromosome and the male-provided sperm contributes either an X chromosome or a Y chromosome, resulting in female (XX) or male (XY) offspring, respectively. Hormone levels in the male parent affect the sex ratio of sperm in humans. [22]

  3. 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.

  4. Sexual differentiation in humans - Wikipedia

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

    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] Thus, male mammals typically have an X and a Y chromosome (XY), while female mammals typically have two X chromosomes (XX). Chromosomal sex is determined ...

  5. Scientists have finally decoded mysteries of the Y chromosome ...

    www.aol.com/scientists-fully-sequence-human-y...

    People who are assigned male at birth have an X and a Y chromosome, while those assigned female at birth have two X chromosomes. ... a collaborating team of scientists assembled Y chromosomes from ...

  6. Sex-determination system - Wikipedia

    en.wikipedia.org/wiki/Sex-determination_system

    Sex-determination system. Some chromosomal sex determination systems in animals. A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. [1] Most organisms that create their offspring using sexual reproduction have two common sexes and a few less common intersex variations.

  7. X chromosome - Wikipedia

    en.wikipedia.org/wiki/X_chromosome

    The X chromosome is one of the two sex chromosomes in many organisms, including mammals, and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome ...

  8. XYY syndrome - Wikipedia

    en.wikipedia.org/wiki/XYY_syndrome

    MI and MII are the stages of meiosis, while the blue and pink circles are male (sperm) and female (ovum) cells, respectively, and the blue and pink bars are Y- and X-chromosomes, respectively. The purple cell has 2 Y-chromosomes and 1 X-chromosome caused by the ovum fusing with a sperm cell with two Y-chromosomes, which was due to division ...

  9. Y chromosome - Wikipedia

    en.wikipedia.org/wiki/Y_chromosome

    The Y chromosome is one of two sex chromosomes in therian mammals and other organisms.Along with the X chromosome, it is part of the XY sex-determination system, in which the Y is the sex-determining chromosome because the presence of the Y chromosome causes offspring produced in sexual reproduction to be of male sex.