X chromosome
Quick Summary
The X chromosome is one of two types of sex chromosomes, the other being the Y chromosome. In humans and many other mammals, females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The X chromosome carries numerous genes, while the Y chromosome has fewer.123
Sex determination in humans is primarily based on the sex chromosomes. An egg fertilized by an X-bearing sperm results in an XX (female) constitution, while fertilization by a Y-bearing sperm results in an XY (male) constitution. Traits controlled by genes on the X chromosome are called sex-linked. Conditions like red-green color blindness and hemophilia are more common in males because they have only one X chromosome and thus no alternative gene on a Y chromosome to counteract a recessive allele on the X. In females, one of the two X chromosomes is typically inactivated in each cell, a process known as X inactivation.4235
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human diseaseDiseases of genetic origin…are those located on the X chromosomes that have no complementary genes on the Y chromosome. Females have two copies of the X chromosome, but males have an X and a Y chromosome. Because males have only one copy of the X chromosome, any mutation occurring in a gene on…
Read More…are those located on the X chromosomes that have no complementary genes on the Y chromosome. Females have two copies of the X chromosome, but males have an X and a Y chromosome. Because males have only one copy of the X chromosome, any mutation occurring in a gene on…
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human genetic diseaseAbnormalities of the sex chromosomes…few genes, and, although the X chromosome is gene-rich, most of these genes become transcriptionally silent in all but one X chromosome in each somatic cell (i.e., all cells except eggs and sperm) via a process called X inactivation. The phenomenon of X inactivation prevents a female who carries two…
Read More…few genes, and, although the X chromosome is gene-rich, most of these genes become transcriptionally silent in all but one X chromosome in each somatic cell (i.e., all cells except eggs and sperm) via a process called X inactivation. The phenomenon of X inactivation prevents a female who carries two…
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- Xg blood group system
…greatly aided mapping of the X chromosome.
Read More…greatly aided mapping of the X chromosome.
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blood groupBlood groups and genetic linkage…in being located on the X chromosome. Genes carried by the X chromosome are said to be sex-linked. Since the blood groups are inherited in a regular fashion, they can be used as genetic markers in family studies to investigate whether any two particular loci are sited on the same…
Read More…in being located on the X chromosome. Genes carried by the X chromosome are said to be sex-linked. Since the blood groups are inherited in a regular fashion, they can be used as genetic markers in family studies to investigate whether any two particular loci are sited on the same…
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