Analysis of the " X " chromosome - the female sex chromosome - has revealed that women are genetically more complicated than men. Parents were almost always not prepared for the possibility of a sex chromosome anomaly and reacted with confusion. If a mother is a carrier for an X-linked recessive form of EDS, she may have affected or unaffected sons, or carrier or unaffected daughters, depending on the second sex chromosome inherited from the father. However, it is estimated that 3 to 8 percent of girls with a single X chromosome and 12 to 21 percent of females with sex chromosome mosaicism may have normal pubertal development and spontaneous menstrual periods. Home Dictionary Definitions Sex-chromosome. Sex-chromosome meaning.
Snake sex chromosomes say less about sex and more about survival
A sex chromosome , also referred to as an allosome , heterotypical chromosome , or heterochromosome ,   or idiochromosome  is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction. Autosomes differ from allosomes because autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell , whereas members of an allosome pair may differ from one another and thereby determine sex. Nettie Stevens and Edmund Beecher Wilson both independently discovered sex chromosomes in
A second X chromosome contributes to resilience in a mouse model of Alzheimer's disease
Metrics details. Klinefelter syndrome KS , caused by XXY karyotype, is characterized by low testosterone, infertility, cognitive deficits, and increased prevalence of health problems including obesity and diabetes. It has been difficult to separate direct genetic effects from hormonal effects in human studies or in mouse models of KS because low testosterone levels are confounded with sex chromosome complement. The independence of sex chromosome complement and gonadal type allows for improved recognition of sex chromosome effects that are not dependent on levels of gonadal hormones.
The XY sex-determination system is a sex-determination system used to classify many mammals , including humans , some insects Drosophila , some snakes, some fish guppies , and some plants Ginkgo tree. In this system, the sex of an individual is determined by a pair of sex chromosomes. Females typically 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.