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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. [25]
XY complete gonadal dysgenesis, also known as Swyer syndrome, is a type of defect hypogonadism in a person whose karyotype is 46,XY. Though they typically have normal vulvas , [ 1 ] the person has underdeveloped gonads, fibrous tissue termed " streak gonads ", and if left untreated, will not experience puberty .
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).
Individuals can either have sex chromosomes generally linked with being female (XX chromosomes) or usually associated with being a man (XY chromosomes), yet have reproductive organs and genitals ...
In this system, females have two of the same kind of sex chromosome (XX), while males have two distinct sex chromosomes (XY). The X and Y sex chromosomes are different in shape and size from each other, unlike the rest of the chromosomes ( autosomes ), and are sometimes called allosomes .
The X-chromosome carries a larger number of genes in comparison to the Y-chromosome. In humans, X-chromosome inactivation enables males and females to have an equal expression of the genes on the X-chromosome since females have two X-chromosomes while males have a single X and a Y chromosome. X-chromosome inactivation is random in the somatic ...
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 the 23rd chromosome in the ovum, while either an X ...
46,XX/46,XY is an example of tetragametic chimerism because it requires four gametes – two sperm and two ova. 46,XX/46,XY is most commonly explained during in conception combination of two fertilized eggs zygotes. Two ova from the mother are fertilized by two sperm from the father. One sperm contains an X chromosome; the other contains a Y ...