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...

has XY chromosomes, but the SRY gene has been shut down. In most species with XY sex determination, an organism must have at least one X chromosome in order...

X-inactivation (also called Lyonization, after English geneticist Mary Lyon) is a process by which one of the copies of the X chromosome is inactivated...

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...

their chromosomal arms. The 23rd pair of chromosomes are called allosomes. These consist of two X chromosomes in females, and an X chromosome and a Y...

X chromosome reactivation (XCR) is the process by which the inactive X chromosome (the Xi) is re-activated in the cells of eutherian female mammals. Therian...

also known as 45,X, or 45,X0, is a genetic disorder in which a female is partially or completely missing an X chromosome (sex chromosome monosomy). Most...

one X chromosome, and transcribe all information from the other, expressed X chromosome. Thus, human females have the same number of expressed X-linked...

X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be always expressed...

X, also known as triple X syndrome and characterized by the karyotype 47,XXX, is a chromosome disorder in which a female has an extra copy of the X chromosome...

present on a sex chromosome (allosome) rather than a non-sex chromosome (autosome). In humans, these are termed X-linked recessive, X-linked dominant and...

Pentasomy X, also known as 49,XXXXX, is a chromosomal disorder in which a female has five, rather than two, copies of the X chromosome. Pentasomy X is associated...

male usually carries an X and a Y chromosome (XY), and the female usually carries two X chromosomes (XX). Other chromosomal sex-determination systems...

also known as 47,XXY, is a chromosome anomaly where a male has an extra X chromosome. As the presence of a Y chromosome denotes male sex, people with...

within the FMR1 (fragile X messenger ribonucleoprotein 1) gene on the X chromosome. This results in silencing (methylation) of this part of the gene and...

called sister chromatids. During metaphase, the X-shaped structure is called a metaphase chromosome, which is highly condensed and thus easiest to distinguish...

gene is carried on the X chromosome. As an inheritance pattern, it is less common than the X-linked recessive type. In medicine, X-linked dominant inheritance...

Tetrasomy X, also known as 48,XXXX, is a chromosomal disorder in which a female has four, rather than two, copies of the X chromosome. It is associated...

females are the heterogametic sex (ZW). The Z chromosome is larger and has more genes, similarly to the X chromosome in the XY system. No genes are shared between...

Aerus Trisomy X, also known as triple X syndrome or XXX syndrome, a chromosomal disorder in which a female has an extra copy of the X chromosome All pages...

X chromosomes. In contrast, male placental mammals, including chromosomally stable male cats, have one X and one Y chromosome. Since the Y chromosome...

Skewed X-chromosome inactivation (skewed X-inactivation) occurs when the X-inactivation of one X chromosome is favored over the other, leading to an uneven...

By contrast, the allosome pair consists of two X chromosomes in females or one X and one Y chromosome in males. Unusual combinations of XYY, XXY, XXX...

number of chromosomes is restored via duplication of the single monosomic chromosome ("chromosome rescue"). Complete loss of an entire X chromosome accounts...

Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary...

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...

A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their...

Barr) or X-chromatin is an inactive X chromosome. In species with XY sex-determination (including humans), females typically have two X chromosomes, and one...

of X-inactivation, in which one of the X chromosomes is turned off at random in each cell in very early embryonic development. The inactivated X becomes...

offspring. In this system, there is only one sex chromosome, referred to as X. Males only have one X chromosome (XO), while females have two (XX). The letter...